Implementing a scheme for system-wide automatic Suspend to RAM in Lubuntu 20.10

Lubuntu 20.10 is installed on my family’s desktop PC (single-seat, multi-user). This version of the distribution uses the SDDM display manager and the LXQt desktop environment. Previously the machine had Lubuntu 18.04 installed, which used the LightDM display manager and the LXDE desktop environment.

In Lubuntu 18.04 each user could configure the power manager in their LXDE session to make the machine suspend to RAM if that user was logged-in but had not used the keyboard and mouse for a user-specified number of minutes. The problem with that approach was that, if two or more users happened to be logged-in simultaneously because a user did not log out and another user used ‘Switch User’ in LXDE to log-in, the power manager in a logged-in but unused session would eventually suspend the machine even though another user was still active in a different session. Very annoying. Secondly, if nobody was logged-in and the LightDM greeter screen was displayed, the machine would not suspend to RAM automatically after a period of inactivity; the only way to get the machine to suspend to RAM if nobody was logged-in was to suspend it manually from the greeter screen. I implemented my own fix for both problems in Lubuntu 18.04 (see my previous blog posts How to make LightDM suspend to RAM automatically from the login screen and lock screen in Lubuntu 18.04 and How to stop inactive user sessions triggering Suspend to RAM in a single-seat, multi-user installation of Lubuntu 18.04) but I had to use a different approach in Lubuntu 20.10 because it uses SDDM and LXQt.

The new scheme I implemented in Lubuntu 20.10 is partly an academic exercise because LXQt in Lubuntu 20.10 does not have a ‘Switch User’ option that would enable more than one user to be logged in simultaneously. LXQt Issue 14 and SDDM Issue 991 appear to be about this limitation. Furthermore, I think systemd may also be a factor (Lubuntu uses Version 246, which no longer includes seat_can_multi_session() that the version of SDDM in Lubuntu 20.10 may depend on for the ‘Switch User’ option). The disappearance of a ‘Switch User’ option has been reported previously for various Linux distributions using KDE and systemd 246, such as Arch Linux, Gentoo Linux and Kubuntu. Therefore it may be that all three packages would need to be altered in order for Lubuntu to provide a ‘Switch User’ option. Anyway, the scheme I have implemented in Lubuntu 20.10 could handle more than one user logged-in simultaneously if that were possible, as I catered for that possibility in case future updates to LXQt and SDDM have a ‘Switch User’ option. Even without a ‘Switch User’ option in LXQt, my scheme enables Lubuntu 20.10 to suspend to RAM automatically when no one is logged in and the SDDM greeter screen is displayed, which is also useful. Furthermore, my scheme also provides system-wide Suspend to RAM control, removing the need for users to touch the LXQt power manager settings in their individual user accounts.

Note that, as was the case in Lubuntu 18.04, Lubuntu 20.10 does not terminate all the user’s processes when the user logs out. This can be seen if you use the ‘ps -ef‘ command when logged in as a different user. Also, the user’s session is not closed; its state is always shown as ‘closing’ if you use the ‘loginctl list-sessions‘ and ‘loginctl session-status <ID>‘ commands. I suspect this behaviour is a ‘feature’ of systemd rather than Lubuntu itself, but I could be wrong. Anyway, in order to cater for this behaviour my scheme is more complex than it would be otherwise.

By the way, I believe this scheme would probably work in other Linux distributions that use systemd and have a desktop environment that can be configured to launch scripts automatically at login. In fact, the scheme could also be adapted for use in a distribution that does not use systemd. For example, in an installation that uses OpenRC the suspend.sh script (see further down) could be launched at boot from a script in the /etc/local.d/ directory. In distributions without systemd the logger command could be used to log messages in the system log file.

My scheme to provide system-wide automatic Suspend to RAM in Lubuntu 20.10 is detailed below. If new versions of LXQt, SDDM and systemd (whichever of those is required for a ‘Switch User’ option) are added to the Lubuntu repositories in future, hopefully the scheme detailed below already caters for that option.

1. Select ‘Preferences’ > ‘LXQt settings’ > ‘Power Management’ in each user’s LXQt account, click on ‘Idle’ and untick ‘Enable Idleness Watcher’ to prevent LXQt Power Manager in each user’s LXQt session from suspending to RAM independently.

Note: It is possible for the system administrator to configure this for all users via the command line instead. For example:

$ nano ~/.config/lxqt/lxqt-powermanagement.conf

Change ‘enableIdlenessWatcher=true‘ to ‘enableIdlenessWatcher=false‘:

[General]
__userfile__=true
backlightIdleness=0
backlightIdlenessOnBatteryDischarging=true
enableBatteryWatcher=false
enableIdlenessBacklightWatcher=false
enableIdlenessWatcher=false
enableLidWatcher=false
idlenessAction=-1
idlenessTime=@Variant(\0\0\0\xf\0\0\x3\xe8)
idlenessTimeSecs=900
runCheckLevel=1
$ $ ls -la ~/.config/lxqt/lxqt-powermanagement.conf
-rw-rw-r-- 1 fitzcarraldo fitzcarraldo 304 Feb  8 22:10 /home/bill/.config/lxqt/lxqt-powermanagement.conf
$ sudo cp ~/.config/lxqt/lxqt-powermanagement.conf /home/aquilino/.config/lxqt/lxqt-powermanagement.conf
$ sudo chown aquilino.aquilino /home/aquilino/.config/lxqt/lxqt-powermanagement.conf
$ sudo chmod 664 /home/aquilino/.config/lxqt/lxqt-powermanagement.conf

and so on for every user. For example, if the installation has accounts for five users with usernames aquilino, cholo, fitzcarraldo, molly and paul:

$ sudo updatedb; sudo locate lxqt-powermanagement.conf | grep .config                                      
/home/aquilino/.config/lxqt/lxqt-powermanagement.conf
/home/cholo/.config/lxqt/lxqt-powermanagement.conf
/home/fitzcarraldo/.config/lxqt/lxqt-powermanagement.conf
/home/molly/.config/lxqt/lxqt-powermanagement.conf
/home/paul/.config/lxqt/lxqt-powermanagement.conf

2. Install the X Windows utility xprintidle so it can be used in a Bash script to determine when a user is idle or active:

$ sudo apt install xprintidle

3. Create the script /usr/local/bin/check_if_idle.sh

An instance of this script will be launched when each user logs in to the desktop environment (see Step 4). Each instance of the script will run continuously and its purpose is to create periodically a file with a specific name, or periodically delete files with specific names, in the RAM-based /tmp/ directory. These zero-length files are used to inform the suspend.sh script (see Step 5) whether or not the applicable user has been using the keyboard or mouse within a specified timeout period (specified as 15 minutes in the script). From now on I will use the term ‘flag-files’ when referring to such files, as they are effectively Boolean flags to pass binary information from a Bash script in each user’s session to a Bash script that actually initiates suspending to RAM. If the active user’s session has been idle for the specified timeout period, the script deletes all that user’s flag-files in order to indicate to the suspend.sh script that the specific user is no longer an impediment to suspending to RAM. Similarly, when the user logs out, the applicable flag-file is deleted in order to indicate to the suspend.sh script that the user is no longer an impediment to suspending. The flag-file is not deleted if the user is logged in but not the active user, in order to indicate to the suspend.sh script that it must not suspend to RAM unless the active user has been idle for the specified timeout period (notice that the script check_if_idle.sh deletes all the user’s non-VT (Virtual Terminal, a.k.a. ‘TTY console’) flag-files when the active user has been idle for the specified timeout period).

$ sudo nano /usr/local/bin/check_if_idle.sh
#!/bin/bash
CurrentUser=$(whoami)
touch /tmp/not_idle_$CurrentUser$BASHPID
IdleAfter=900000 # consider idle after 900000 ms (15 min) of inactivity
while true; do
  State=$( loginctl session-status | grep -m 1 State | awk -F " " '{ print $2 }' )
  if [[ "$State" == "active" ]]; then
  IdleTimeMillisecs=$(xprintidle 2>/dev/null)
    if [[ $IdleTimeMillisecs -ge $IdleAfter ]]; then
      rm /tmp/not_idle_$CurrentUser* 2>/dev/null
    fi
    if [[ $IdleTimeMillisecs -lt $IdleAfter ]]; then
      touch /tmp/not_idle_$CurrentUser$BASHPID
    fi
  elif [[ "$State" == "online" ]]; then
    touch /tmp/not_idle_$CurrentUser$BASHPID
  elif [[ "$State" == "closing" ]]; then
    rm /tmp/not_idle_$CurrentUser$BASHPID 2>/dev/null
  fi
  sleep 1
done
$ chmod 755 /usr/local/bin/check_if_idle.sh

As far as I have been able to ascertain from systemd documentation, currently the following three session states are possible: “online” (session logged in, but session not active, i.e. not in the foreground), “active” (session logged in and active, i.e. in the foreground), “closing” (session nominally logged out, but some processes belonging to it are still around).

Note: I could have created a separate configuration file and made the Bash script read $IdleAfter from it, but I decided to keep things simple and specify the time-out period in the script itself.

4. Add the following command to LXQt Application Menu > Preferences > LXQt settings > Session Settings > Autostart > LXQt Autostart for each user (give it the name ‘Check_if_idle’) so that an instance of check_if_idle.sh is launched automatically when a user logs in:

/usr/local/bin/check_if_idle.sh

Note: It is possible for the system administrator to configure this for all users via the command line instead. For example:

$ nano ~/.config/autostart/Check_if_idle.desktop
[Desktop Entry]
Exec=/usr/local/bin/check_if_idle.sh
Name=Check_if_idle
OnlyShowIn=LXQt;
Type=Application
Version=1.0
$ ls -la ~/.config/autostart/Check_if_idle.desktop
-rw-rw-r-- 1 fitzcarraldo fitzcarraldo 118 Feb  9 13:27 /home/fitzcarraldo/.config/autostart/Check_if_idle.desktop
$ sudo cp ~/.config/autostart/Check_if_idle.desktop /home/aquilino/.config/autostart/Check_if_idle.desktop
$ sudo chown aquilino.aquilino /home/aquilino/.config/autostart/Check_if_idle.desktop
$ sudo chmod 664 /home/aquilino/.config/autostart/Check_if_idle.desktop

and so on for every user. For example, if the installation has accounts for five users with usernames aquilino, cholo, fitzcarraldo, molly and paul:

$ sudo updatedb; sudo locate Check_if_idle.desktop
/home/aquilino/.config/autostart/Check_if_idle.desktop
/home/cholo/.config/autostart/Check_if_idle.desktop
/home/fitzcarraldo/.config/autostart/Check_if_idle.desktop
/home/molly/.config/autostart/Check_if_idle.desktop
/home/paul/.config/autostart/Check_if_idle.desktop

5. Create the script /usr/local/bin/suspend.sh

This script will be a service launched at boot via a systemd unit file. Its purpose is twofold:

  • to check periodically if there has been keyboard and mouse activity while the SDDM greeter screen is displayed and to suspend to RAM if there has not been any activity within a specificed timeout period (which I have also specified as 15 minutes);
  • to check periodically for flag-files in the /tmp/ directory to ascertain if there has been any activity by logged-in LXQt users within a specified timeout period, and to ascertain if any user is logged in to a VT, and to suspend to RAM if neither of those are the case.
#!/bin/bash
rm /tmp/not_idle_* 2>/dev/null
rm /tmp/triggered_suspend_greeter 2>/dev/null
rm /tmp/triggered_suspend 2>/dev/null
IdleAfter=900000 # Consider SDDM Greeter idle after 900000 ms (15 min) of inactivity
while true; do
  sleep 30 # Do not delete this line or reduce the time
  NumLoggedInUsers=$(who -qs | grep -o '[0-9]\+')
  if [[ $NumLoggedInUsers -eq 0 ]]; then
    rm /tmp/not_idle_* 2>/dev/null
    AuthFile=$(find /var/run/sddm/ -type f)
    if IdleTimeMillisecs=$(DISPLAY=:0 XAUTHORITY=$AuthFile xprintidle 2>/dev/null) ; then
      Running_in_X_Windows=true
    else
      echo "Cannot calc Idle time for Greeter screen." # Log the problem in systemd journal.
      IdleTimeMillisecs=0
      Running_in_X_Windows=false
    fi
    if [[ $IdleTimeMillisecs -gt $IdleAfter ]] ; then
      touch /tmp/triggered_suspend_greeter
      systemctl suspend -i # Comment out when debugging
    fi
  else
    # Only suspend if all users have been idle for the time specified in /usr/local/bin/check_if_idle.sh
    if [[ `ls -1 /tmp/not_idle_* 2>/dev/null | wc -l` -eq 0 ]]; then
      touch /tmp/triggered_suspend
      systemctl suspend -i
    fi
  fi
done
$ sudo chmod 755 /usr/local/bin/suspend.sh

Note: I could have created a separate configuration file and made the Bash script read $IdleAfter from it, but I decided to keep things simple and specify the timeout period in the script itself.

6. Create the systemd unit file /etc/systemd/system/suspend.service so that systemd can launch the suspend.sh script at boot. Note that this service is different to, and independent from, systemd’s service for suspending to RAM (systemd-suspend.service).

[Unit]
Description=Suspend to RAM if idle for specified time

Wants=network.target
After=syslog.target network-online.target

[Service]
Type=simple
ExecStart=/usr/local/bin/suspend.sh
Restart=on-failure
RestartSec=10
KillMode=process

[Install]
WantedBy=multi-user.target
$ sudo chmod 640 /etc/systemd/system/suspend.service
$ sudo systemctl daemon-reload
$ sudo systemctl enable suspend.service

7. Add the following lines to the end of each user’s ~/.profile file:

# Stop /usr/local/bin/suspend.sh suspending to RAM if this user logs in to a VT
CurrentUser=$(whoami)
CurrentVT=$(tty | grep -o '[0-9]\+') # Will be zero if not run on a VT
rm /tmp/not_idle_$CurrentUser* 2>/dev/null
if [[ $CurrentVT -ne 0 ]]; then
  touch /tmp/not_idle_VT"$CurrentVT"_"$CurrentUser"
fi

This addition only creates a flag-file if the applicable user logs in to a VT, and the flag-file is created using a different naming convention to flag-files for LXQt processes in order to be able to distinguish between specific VT console use and pseudo-terminal use, to prevent the suspend.sh script from suspending to RAM while a user is logged in to a VT.

8. Add the following lines to the end of each user’s ~/.bash_logout file:

# Allow /usr/local/bin/suspend.sh to suspend to RAM after this user logs out from a VT session
CurrentUser=$(whoami)
CurrentVT=$(tty | grep -o '[0-9]\+')
if [[ $CurrentVT -ne 0 ]]; then
  rm /tmp/not_idle_VT"$CurrentVT"_"$CurrentUser" 2>/dev/null
fi

The flag-file uses a different naming convention to flag-files used for LXQt processes, in order to be able to indicate to the suspend.sh script that the specific VT user has logged out and therefore is no longer an impediment to suspending to RAM.

9. Create the file /usr/lib/systemd/system-sleep/automatic-suspend-scheme to log when the scheme causes the system to suspend to RAM and also when the system wakes from that suspension.

$ sudo nano /usr/lib/systemd/system-sleep/automatic_suspend_scheme
#!/bin/bash
# This hook script will run when suspending/hibernating and when resuming/thawing.
# Check $1 ('pre' or 'post') and $2 ('suspend', 'hibernate', or 'hybrid-sleep') to ascertain
# which is happening.
case $1/$2 in
  pre/*)
    # Put here any commands you want to be run when suspending or hibernating.
    if [[ -f /tmp/triggered_suspend_greeter ]]; then
      echo "Automatic Suspend Scheme - Suspend to RAM (No users logged in)." # Log the event in the systemd journal
    fi
    if [[ -f /tmp/triggered_suspend ]]; then
      echo "Automatic Suspend Scheme - Suspend to RAM." # Log the event in the systemd journal
    fi
    ;;
  post/*)
    # Put here any commands you want to be run when resuming from suspension or thawing from hibernation.
    if [[ -f /tmp/triggered_suspend_greeter ]]; then
      echo "Automatic Suspend Scheme - Resuming from Suspend to RAM (No users logged in)." # Log the event in the systemd journal
      rm /tmp/triggered_suspend_greeter
    fi
    if [[ -f /tmp/triggered_suspend ]]; then
      echo "Automatic Suspend Scheme - Resuming from Suspend to RAM." # Log the event in the systemd journal
      rm /tmp/triggered_suspend
    fi
    ;;
esac
$ sudo chmod 755 /usr/lib/systemd/system-sleep/automatic_suspend_scheme

10. Reboot and test

From now on, the installation should suspend to RAM if all logged-in LXQt users have been inactive for 15 minutes or more. This does not preclude any user selecting Leave > Suspend from the LXQt Application Menu to suspend to RAM manually. If no users are logged in — i.e. the SDDM greeter screen is displayed on the monitor — the installation will suspend to RAM if there is no keyboard and mouse activity for 15 minutes. This does not preclude any user clicking on the icon on the SDDM greeter screen to suspend the machine to RAM manually. The Bash scripts suspend.sh and check_if_idle.sh can be edited to alter the timeout period if a different timeout is desired. The scheme will not trigger suspending to RAM while someone is logged in via a VT (a.k.a. TTY console). I am the only person in my family who knows how to use a VT; all the other family members use only the LXQt desktop environment.

Caveat: The suspend.sh script can initiate suspending to RAM if no /tmp/not_idle_* files exist, so do not delete manually any of the not_idle_* files in the /tmp/ directory.

If you want to check what is happing to the sessions, processes and flag-files, the following commands are useful:

$ systemctl status suspend
$ ps -ef | grep check
$ ps -ef | grep suspend
$ ls /tmp/not_idle*
$ loginctl list-sessions
$ loginctl session-status <session number> | grep State

For example, below is some output from those commands when users paul and aquilino were using the machine. User paul booted the machine and logged-in on the SDDM greeter screen, then logged out to let user aquilino login on the SDDM greeter screen. Then user aquilino logged out and user paul logged in again on the SDDM greeter screen and entered the following commands in a pseudo-terminal (e.g. QTerminal) window:

$ systemctl status suspend
● suspend.service - Suspend to RAM if idle for specified time
     Loaded: loaded (/etc/systemd/system/suspend.service; enabled; vendor preset: enabled)
     Active: active (running) since Thu 2021-02-11 16:25:53 GMT; 35min ago
   Main PID: 966 (suspend.sh)
      Tasks: 2 (limit: 4476)
     Memory: 1.5M
     CGroup: /system.slice/suspend.service
             ├─  966 /bin/bash /usr/local/bin/suspend.sh
             └─36254 sleep 30

Feb 11 16:25:53 aspirexc600 systemd[1]: Started Suspend to RAM if idle for specified time.
$ ps -ef | grep check
paul        1337       1  0 16:27 ?        00:00:01 /bin/bash /usr/local/bin/check_if_idle.sh
aquilino    4904       1  0 16:34 ?        00:00:01 /bin/bash /usr/local/bin/check_if_idle.sh
paul        9187       1  0 16:38 ?        00:00:01 /bin/bash /usr/local/bin/check_if_idle.sh
paul       37124    9236  0 17:01 pts/0    00:00:00 grep --color=auto check
$ ps -ef | grep suspend
root         966       1  0 16:25 ?        00:00:00 /bin/bash /usr/local/bin/suspend.sh
paul       38515    9236  0 17:02 pts/0    00:00:00 grep --color=auto suspend
$ ls /tmp/not_idle*
/tmp/not_idle_paul9187
$ loginctl list-sessions
SESSION  UID USER     SEAT  TTY
     12 1000 paul     seat0    
      3 1000 paul     seat0    
      8 1001 aquilino seat0    

3 sessions listed.
$ loginctl session-status 12 | grep State
           State: active
                  └─41171 grep --color=auto State
$ loginctl session-status 3 | grep State
           State: closing
$ loginctl session-status 8 | grep State
           State: closing

Then user paul pressed Ctrl+Alt+F2 to switch to VT2 (tty2), logged in as user paul and entered the commands:

$ ps -ef | grep check
paul        1337       1  0 16:27 ?        00:00:01 /bin/bash /usr/local/bin/check_if_idle.sh
aquilino    4904       1  0 16:34 ?        00:00:01 /bin/bash /usr/local/bin/check_if_idle.sh
paul        9187       1  0 16:38 ?        00:00:01 /bin/bash /usr/local/bin/check_if_idle.sh
paul       50191   48181  0 17:12 tty2     00:00:00 grep --color=auto check
$ ps -ef | grep suspend
root         966       1  0 16:25 ?        00:00:00 /bin/bash /usr/local/bin/suspend.sh
paul       50295   48181  0 17:12 tty2     00:00:00 grep --color=auto suspend
$ ls /tmp/not_idle*
/tmp/not_idle_paul9187  /tmp/not_idle_VT2_paul
$ loginctl list-sessions
SESSION  UID USER     SEAT  TTY
     12 1000 paul     seat0    
     15 1000 paul     seat0 tty2
      3 1000 paul     seat0    
      8 1001 aquilino seat0    

4 sessions listed.
$ loginctl session-status 12 | grep State
           State: online
$ loginctl session-status 15 | grep State
           State: active
                  └─50741 grep --color=auto State
$ loginctl session-status 3 | grep State
           State: closing
$ loginctl session-status 8 | grep State
           State: closing

Then user paul pressed Ctrl+Alt+F1 to switch back to his LXQt session and entered the following commands in the already open pseudo-terminal window:

$ ps -ef | grep check
paul        1337       1  0 16:27 ?        00:00:02 /bin/bash /usr/local/bin/check_if_idle.sh
aquilino    4904       1  0 16:34 ?        00:00:02 /bin/bash /usr/local/bin/check_if_idle.sh
paul        9187       1  0 16:38 ?        00:00:02 /bin/bash /usr/local/bin/check_if_idle.sh
paul       61359    9236  0 17:22 pts/0    00:00:00 grep --color=auto check
$ ps -ef | grep suspend
root         966       1  0 16:25 ?        00:00:00 /bin/bash /usr/local/bin/suspend.sh
paul       61473    9236  0 17:22 pts/0    00:00:00 grep --color=auto suspend
$ ls /tmp/not_idle*
/tmp/not_idle_paul9187  /tmp/not_idle_VT2_paul
$ loginctl list-sessions
SESSION  UID USER     SEAT  TTY 
     12 1000 paul     seat0     
     15 1000 paul     seat0 tty2
      3 1000 paul     seat0     
      8 1001 aquilino seat0     

4 sessions listed.
$ loginctl session-status 12 | grep State
           State: active
                  └─62165 grep --color=auto State
$ loginctl session-status 15 | grep State
           State: online
$ loginctl session-status 3 | grep State
           State: closing
$ loginctl session-status 8 | grep State
           State: closing

Then user paul pressed Ctrl+Alt+F2 to switch back to tty2, entered ‘exit‘ to log out of his VT session, then pressed Ctrl+Alt+F1 to switch back to his LXQt session and entered the following commands:

$ ps -ef | grep check
paul        1337       1  0 16:27 ?        00:00:03 /bin/bash /usr/local/bin/check_if_idle.sh
aquilino    4904       1  0 16:34 ?        00:00:03 /bin/bash /usr/local/bin/check_if_idle.sh
paul        9187       1  0 16:38 ?        00:00:03 /bin/bash /usr/local/bin/check_if_idle.sh
paul       92759    9236  0 17:48 pts/0    00:00:00 grep --color=auto check
$ ps -ef | grep suspend
root         966       1  0 16:25 ?        00:00:00 /bin/bash /usr/local/bin/suspend.sh
paul       92922    9236  0 17:48 pts/0    00:00:00 grep --color=auto suspend
$ ls /tmp/not_idle*
/tmp/not_idle_paul9187
$ loginctl list-sessions
SESSION  UID USER     SEAT  TTY
     12 1000 paul     seat0    
      3 1000 paul     seat0    
      8 1001 aquilino seat0    

3 sessions listed.
$ loginctl session-status 12 | grep State
           State: active
                  └─93554 grep --color=auto State
$ loginctl session-status 3 | grep State
           State: closing
$ loginctl session-status 8 | grep State
           State: closing

As you can see in the output above, even though user paul logged out of his first LXQt session (Session 3), and user aquilino logged out of his only LXQt session (Session 8), those two sessions did not end, remaining in the state ‘closing’. You can also see that user paul‘s VT session (Session 15) did close when he logged out on VT2 (tty2). Addiionally, you can see in the output above the flag-files that were created and deleted during that period.

The following command shows the entries in the systemd journal for the scheme’s service (suspend.service) since the system last booted:

$ journalctl -b -u suspend.service
-- Logs begin at Sat 2021-01-02 01:52:36 GMT, end at Sat 2021-02-13 01:16:09 GMT. --
Feb 13 00:24:18 aspirexc600 systemd[1]: Started Suspend to RAM if idle for specified time.

The above output shows no error messages since the service started at 00:24:18 when the system was last booted.

If you want to check the systemd journal to see when the scheme suspended the system to RAM automatically and was manually woken up from that sleep:

$ journalctl | grep "Automatic Suspend Scheme"

Add ‘-b‘ if you want to check only since the system last booted:

$ journalctl -b | grep "Automatic Suspend Scheme"
Feb 13 00:39:49 aspirexc600 systemd-sleep[1611]: Automatic Suspend Scheme - Suspend to RAM (No users logged in).
Feb 13 00:44:32 aspirexc600 systemd-sleep[1691]: Automatic Suspend Scheme - Resuming from Suspend to RAM (No users logged in).
Feb 13 01:01:59 aspirexc600 systemd-sleep[10470]: Automatic Suspend Scheme - Suspend to RAM.
Feb 13 01:04:52 aspirexc600 systemd-sleep[10556]: Automatic Suspend Scheme - Resuming from Suspend to RAM.

The following command shows entries in the systemd journal by the systemd suspend service (systemd-suspend.service) and systemd-sleep command since the system last booted, so it is possible to check both the times at which the automated scheme suspended and the times at which the system was manually suspended, and also the times at which the system was woken manually:

$ journalctl -b -u systemd-suspend.service
-- Logs begin at Sat 2021-01-02 01:52:36 GMT, end at Sat 2021-02-13 01:16:09 GMT. --
Feb 13 00:39:49 aspirexc600 systemd[1]: Starting Suspend...
Feb 13 00:39:49 aspirexc600 systemd-sleep[1611]: Automatic Suspend Scheme - Suspend to RAM (No users logged in).
Feb 13 00:39:49 aspirexc600 systemd-sleep[1609]: Suspending system...
Feb 13 00:44:32 aspirexc600 systemd-sleep[1609]: System resumed.
Feb 13 00:44:32 aspirexc600 systemd-sleep[1691]: Automatic Suspend Scheme - Resuming from Suspend to RAM (No users logged in).
Feb 13 00:44:32 aspirexc600 systemd[1]: systemd-suspend.service: Succeeded.
Feb 13 00:44:32 aspirexc600 systemd[1]: Finished Suspend.
Feb 13 01:01:59 aspirexc600 systemd[1]: Starting Suspend...
Feb 13 01:01:59 aspirexc600 systemd-sleep[10470]: Automatic Suspend Scheme - Suspend to RAM.
Feb 13 01:01:59 aspirexc600 systemd-sleep[10468]: Suspending system...
Feb 13 01:04:51 aspirexc600 systemd-sleep[10468]: System resumed.
Feb 13 01:04:52 aspirexc600 systemd-sleep[10556]: Automatic Suspend Scheme - Resuming from Suspend to RAM.
Feb 13 01:04:51 aspirexc600 systemd[1]: systemd-suspend.service: Succeeded.
Feb 13 01:04:51 aspirexc600 systemd[1]: Finished Suspend.
Feb 13 01:12:51 aspirexc600 systemd[1]: Starting Suspend...
Feb 13 01:12:51 aspirexc600 systemd-sleep[14964]: Suspending system...
Feb 13 01:15:50 aspirexc600 systemd-sleep[14964]: System resumed.
Feb 13 01:15:53 aspirexc600 systemd[1]: systemd-suspend.service: Succeeded.
Feb 13 01:15:53 aspirexc600 systemd[1]: Finished Suspend.

You can see above that the system automatically suspended to RAM at 00:39:49 after 15 minutes of inactivity on the SDDM greeter screen. Someone then pressed the space bar on the keyboard to wake the system at 00:44:32, and logged in to the LXQt desktop. The system suspended to RAM automatically again at 01:01:59 after that user had not touched the keyboard and mouse for 15 minutes in the active LXQt session. That user then woke the system manually again at 01:04:52, then manually suspended the system at 01:12:51 using the LXQt Application Menu (Leave > Suspend). Finally, at 01:15:50 the same user woke the system manually again.

11. Make /tmp/ RAM-based (optional)

By default, the Lubuntu 20.10 Installer creates the directory /tmp/ on the same disk partition as the root directory:

$ df -h /tmp
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda2       916G  139G  731G  16% /

If your machine has plenty of RAM, if you want you could configure the system to mount a tmpfs filesystem on /tmp/ instead, as show below.

I decided to specify a tmpfs maximum size of 200MB for /tmp/ (tmpfs doesn’t reserve this memory, it allocates only the memory actually needed):

$ echo "tmpfs /tmp tmpfs rw,nosuid,nodev,size=200M" | sudo tee -a /etc/fstab
$ grep tmp /etc/fstab
tmpfs /tmp tmpfs rw,nosuid,nodev,size=200M

Note: If I had not included ‘,size=200M‘ in /etc/fstab, the maximum size for the tmpfs filesystem mounted on /tmp/ would have defaulted to half the available RAM in the machine.

Then I rebooted to check that /tmp/ is now in RAM:

$ df -h /tmp/
Filesystem      Size  Used Avail Use% Mounted on
tmpfs           200M  4.0K  200M   1% /tmp
$ findmnt /tmp/
TARGET SOURCE FSTYPE OPTIONS
/tmp   tmpfs  tmpfs  rw,nosuid,nodev,relatime,size=204800k

The space used in /tmp/ will vary depending on what is running. For example, editing a large LibreOffice document will require space in /tmp/, so keep an eye on the amount of space used in /tmp/ and adjust the maximum size of the tmpfs partition if necessary.

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Preventing Lubuntu 18.04 from leaving a user process running after the user logs out

My family’s desktop machine has Lubuntu 18.04 installed, which uses systemd and the LXDE desktop environment. Each family member has their own user account, thus the installation is a single-seat, multi-user installation. For each user’s account I set up the virus-checking scheme described in an earlier post, suitably modified to take into account the differences between Lubuntu 18.04 and Gentoo Linux running KDE. For example, the monitorDownloadsGUI script in Lubuntu 18.04 uses zenity rather than kdialog, and, as Lubuntu 18.04 uses systemd, the ClamAV daemon’s service file in Lubuntu 18.04 is /lib/systemd/system/clamav-daemon.service rather than the OpenRC init file /etc/init.d/clamd used in my Gentoo Linux installations.

The virus-checking script ~/.monitorDownloadGUI in each user’s home directory is launched automatically by LXDE at login because I created a Desktop Configuration File ~/.config/autostart/monitorDownloadsGUI.desktop in each user’s account. For example, the contents of the file in my account are as follows:

[Desktop Entry]
Type=Application
Exec=/home/fitzcarraldo/.monitorDownloadsGUI

However, I recently noticed that Lubuntu 18.04 does not terminate the monitorDownloadsGUI process when the user logs out. I do not see this behaviour on my laptops running Gentoo Linux with OpenRC and KDE, so I am not sure why this is happening in Lubuntu 18.04 with systemd and LXDE. The output of the ‘ps -ef‘ command after each of the three example steps shown below illustrates the behaviour.

Step 1. george is the only user who is logged-in.

$ ps -ef | grep bash | grep -v grep
george    1410     1  0 02:05 ?        00:00:00 /bin/bash /home/george/.monitorDownloadsGUI
george    1597  1358  0 02:05 pts/0    00:00:00 /bin/bash

Step 2. ringo uses ‘Logout’ > ‘Switch User’ to login to his account.

$ ps -ef | grep bash | grep -v grep
george    1410     1  0 02:05 ?        00:00:00 /bin/bash /home/george/.monitorDownloadsGUI
george    1597  1358  0 02:05 pts/0    00:00:00 /bin/bash
ringo     2382     1  0 02:06 ?        00:00:00 /bin/bash /home/ringo/.monitorDownloadsGUI

Step 3. ringo logs out of his account.

$ ps -ef | grep bash | grep -v grep
george    1410     1  0 02:05 ?        00:00:00 /bin/bash /home/george/.monitorDownloadsGUI
george    1597  1358  0 02:05 pts/0    00:00:00 /bin/bash
ringo     2382     1  0 02:06 ?        00:00:00 /bin/bash /home/ringo/.monitorDownloadsGUI

Notice that the process with PID 2382 is still running, even though user ringo is no longer logged in.

If a user logs out and logs in again, or if users switch between sessions using ‘Logout’ > ‘Switch User’, it is also possible for multiple instances of the script per user to be running. For example:

$ ps -ef | grep bash | grep -v grep
george    1564     1  0 11:14 ?        00:00:00 /bin/bash /home/george/.monitorDownloadsGUI
ringo     2522     1  0 11:16 ?        00:00:00 /bin/bash /home/ringo/.monitorDownloadsGUI
george    3803     1  0 11:17 ?        00:00:00 /bin/bash /home/george/.monitorDownloadsGUI
george    5997     1  0 11:19 ?        00:00:00 /bin/bash /home/george/.monitorDownloadsGUI
george    6054  5881  0 11:19 pts/0    00:00:00 /bin/bash

Notice that several instances of the script are running for user george. There should only be one instance.

In order to prevent these multiple instances, I added the shell script lines below to the existing LightDM session-cleanup-script that I had created previously to solve a different problem in the Lubuntu 18.04 installation (see an earlier blog post).

# Get rid of duplicate instances (if any) per user of the virus-checker script's process
who -u | grep -v "\." > /tmp/logged-in_users
while IFS=: read -r f1 f2 f3 f4 f5 f6 f7
# $f1 is username
# $f2 is password ('x')
# $f3 is UID
# $f4 is GID
# $f5 is UID info
# $f6 is home directory
# $f7 is command/shell
do
    match=0
    while read a b c d e f g h # Use this if this script is launched by LightDM in Lubuntu 18.04
#    while read a b c d e f g # Use this if you launch this script from a terminal in Lubuntu 18.04
    #
    # If this script is launched by a user, 'who -u' returns the following fields:
    # "john     tty7         2019-08-31 17:08 00:01        1624 (:0)"
    # If this script is launched by LightDM, 'who -u' returns the following fields:
    # "john     tty7        Aug 31 17:08 00:01        1624 (:0)"
    #
    do
        if [[ $f6 == *"/home/"* ]] && [[ $f7 == "/bin/bash" ]] && [[ $a == $f1 ]]; then
            match=1
            user=$f1
            tty=$b
        fi
    done < /tmp/logged-in_users
    if [[ $match -eq 1 ]] && [[ $(echo $tty | sed 's/[^0-9]*//g') -gt 6 ]]; then
        if [[ `ps -ef | grep bash | grep "$user" | grep monitorDownloadsGUI | awk -F' ' '{print $2}' | wc -l` -gt 1 ]]; then
            kill `ps -ef | grep bash | grep "$user" | grep monitorDownloadsGUI | awk -F' ' '{print $2}' | tail -n +2`
        fi
    elif [[ $match -ne 1 ]]; then
        if [[ $f6 == *"/home/"* ]] && [[ $f7 == "/bin/bash" ]] && [[ `ps -ef | grep bash | grep "$f1" | grep monitorDownloadsGUI | awk -F' ' '{print $2}' | wc -l` -gt 1 ]]; then
            kill `ps -ef | grep bash | grep "$f1" | grep monitorDownloadsGUI | awk -F' ' '{print $2}' | tail -n +2`
        elif [[ $f6 == *"/home/"* ]] && [[ $f7 == "/bin/bash" ]] && [[ `ps -ef | grep bash | grep "$f1" | grep monitorDownloadsGUI | awk -F' ' '{print $2}' | wc -l` -eq 1 ]]; then
            kill `ps -ef | grep bash | grep "$f1" | grep monitorDownloadsGUI | awk -F' ' '{print $2}'`
        fi
    fi
done < /etc/passwd
rm /tmp/logged-in_users

The above lines of Bash script kill additional instances of monitorDownloadGUI on a per-user basis when a user session ends. If LightDM’s session-cleanup-script does this, there will be no more than one instance of a monitorDownloadsGUI process per logged-in user, and no instances of a monitorDownloadGUI process for users who have logged out:

$ ps -ef | grep bash | grep -v grep
george    1473     1  0 12:32 ?        00:00:00 /bin/bash /home/george/.monitorDownloadsGUI
george    1693  1412  0 12:32 pts/0    00:00:00 /bin/bash

Problem solved. Well, worked around. I would like to know what causes the problem to happen in the first place. I assume it is either systemd or LXDE.

Getting the lock screen to work reliably when resuming from suspension in a single-seat, multi-user Lubuntu 18.04 installation

In an earlier post I described my attempt at getting the lock screen to work reliably in the single-seat, multi-user Lubuntu 17.10 installation on my family’s desktop PC. Although the modifications described in that post seemed to improve matters somewhat, users were still not always able to login from the LightDM greeter screen after resuming from Suspend to RAM in the following situation:

  1. User_A logs in to User_A’s account but does not log out after using the account.
  2. User_B clicks on ‘Logout’ > ‘Switch User’ to log in to User_B’s account but does not log out.
  3. User_A clicks on ‘Logout’ > ‘Switch User’ to get back to User_A’s account.
  4. User_A allows his/her session to timeout and suspend to RAM.
  5. User_B presses a key on the keyboard to resume from suspension, and the LightDM lock screen is displayed.
  6. User_B enters his/her password and then clicks on ‘Unlock’, but the LightDM lock screen remains on display and nobody can log in any more, although the keys on the lock screen are still clickable.

When this occurs, the only way users can access their Desktop is to click on the Power icon in the top right corner of the lock screen and select ‘Restart…’.

The Software Updater in Lubuntu 17.10 recently offered me the choice of upgrading to Lubuntu 18.04, which I accepted. The upgrade was performed and the only hitch that resulted was an incorrect initramfs, which was simple enough to fix (see my post Lubuntu 18.04 ‘Gave up waiting for suspend/resume device’). However, the above-mentioned problem of unlocking after resuming from suspension still occurred in Lubuntu 18.04. Below are the changes I made since the modifications described in my post Getting the lock screen to work properly when resuming from Suspend-to-RAM with multiple sessions in Lubuntu 17.10 (the other changes in that post remain), which seem to have cured the problem.

Change to Item 2 in my earlier post

I reverted the Exec line in /etc/xdg/autostart/light-locker.desktop back to how it was originally following installation of Lubuntu:

user $ grep Exec /etc/xdg/autostart/light-locker.desktop
Exec=light-locker

Change to Item 3 in my earlier post

I deleted the file /lib/systemd/system-sleep/hang-fix that I had previously created:

user $ sudo rm /lib/systemd/system-sleep/hang-fix

Change to Item 7 in my earlier post

The Xfce Power Manager ‘Security’ tab for each user now has ‘Lock screen when system is going for sleep’ ticked:

Light Locker

  • Automatically lock the session: Never
  • Delay locking after screensaver for: ‘1 Seconds’ is greyed out
  • ‘Lock screen when system is going for sleep’ is ticked

The full Xfce Power Manager settings for each user (see the file ~/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-power-manager.xml in each user’s home directory) are now configured as follows:

<?xml version="1.0" encoding="UTF-8"?>

<channel name="xfce4-power-manager" version="1.0">
  <property name="xfce4-power-manager" type="empty">
    <property name="power-button-action" type="empty"/>
    <property name="show-tray-icon" type="empty"/>
    <property name="brightness-switch-restore-on-exit" type="int" value="1"/>
    <property name="brightness-switch" type="int" value="0"/>
    <property name="presentation-mode" type="bool" value="false"/>
    <property name="inactivity-on-ac" type="uint" value="30"/>
    <property name="blank-on-ac" type="int" value="10"/>
    <property name="dpms-on-ac-sleep" type="uint" value="0"/>
    <property name="dpms-on-ac-off" type="uint" value="0"/>
    <property name="brightness-on-ac" type="uint" value="9"/>
    <property name="lock-screen-suspend-hibernate" type="bool" value="true"/>
    <property name="logind-handle-lid-switch" type="bool" value="false"/>
    <property name="dpms-enabled" type="bool" value="false"/>
    <property name="general-notification" type="bool" value="true"/>
  </property>
</channel>

Additional modifications

In another of my posts (Prevent Lubuntu 17.10 from leaving an external HDD mounted incorrectly for other users) I explained the modifications I made in Lubuntu 17.10 for a single-seat, multi-user installation to work properly with a permanently connected external USB HDD. However, I recently noticed the following problems resulting from those modifications:

A. The following error message in the LightDM log file /var/log/lightdm/lightdm.log:

[SeatDefaults] is now called [Seat:*], please update this configuration

So I changed the contents of the file /etc/lightdm/lightdm.conf.d/10_lubuntu.conf from:

[SeatDefaults]
session-cleanup-script=/etc/lightdm/lightdm.conf.d/unmount_FREECOM_HDD.sh

to:

[Seat:*]
session-cleanup-script=/etc/lightdm/lightdm.conf.d/unmount_FREECOM_HDD.sh

B. The following error message in the LightDM log file/var/log/lightdm/lightdm.log when the USB external HDD happened to not be mounted at the time:

DEBUG: Launching process 8569: /etc/lightdm/lightdm.conf.d/unmount_FREECOM_HDD.sh
DEBUG: Process 8569 terminated with signal 11

So I changed the contents of my Bash script /etc/lightdm/lightdm.conf.d/unmount_FREECOM_HDD.sh from:

#!/bin/bash
udisksctl unmount --block-device /dev/disk/by-uuid/C6576A087368B015

to:

#!/bin/bash
STATUS=`mount | grep $(readlink -f /dev/disk/by-uuid/C6576A087368B015 )`
if [[ ! -z $STATUS ]]; then
    udisksctl unmount --block-device /dev/disk/by-uuid/C6576A087368B015
fi
exit 0

Conclusions

It is early days, but so far the login problem for other users after resuming from suspension has not reoccurred since I made the latest changes. I am not sure if the modifications described in my post ‘Prevent Lubuntu 17.10 from leaving an external HDD mounted incorrectly for other users‘ contributed to (or caused) the login problem, or whether one or more of systemd-logind, LightDM, LightDM GTK+ Greeter, Light Locker and Xfce Power Manager are to blame (since they have to work holistically to provide the required functionality). It is frustrating not knowing the root cause of the problem, but at least my family no longer has to worry about being able to log in if a family member has not logged out and left the PC to suspend.

Getting the lock screen to work properly when resuming from Suspend-to-RAM with multiple sessions in Lubuntu 17.10

Introduction

What is it with Linux and lock screens?! There are umpteen posts on the Web by Linux users having trouble with lock screens, particularly the LightDM session locker Light Locker. Well, here is my contribution.

Lubuntu 17.10 is installed on my family’s desktop PC (single seat, multiple users). Lubuntu 17.10 uses systemd-logind, LightDM, Light Locker and Xfce Power Manager, and they do not work properly holistically in my experience. To confuse matters further, Lubuntu 17.10 also has XScreenSaver installed, which also has lock-screen capabilities.

In Lubuntu 17.10 on my family’s desktop PC, Light Locker displays the LightDM GTK+ Greeter screen when anyone wakes/resumes the PC from suspension by pressing a key on the USB keyboard, and users should then be able to log in by selecting their username from the pull-down list on the LightDM GTK+ Greeter screen and entering their password. However, if only a single user session existed when the PC suspended automatically (i.e. by timeout), upon resuming from suspension a black screen with a white padlock icon and the following message in white/grey text from light-locker would appear:

This session is locked
You’ll be redirected to the unlock
dialog automatically in a few seconds

But then nothing else happened; the above-mentioned message remained on display. I could press Ctrl+Alt+F1, login on TTY1 and enter the command ‘loginctl unlock-sessions‘ to get back to the Desktop, but that is not something the rest of my family would know how to do or be comfortable doing. In any case, I have only given sudo rights to one other member of the family.

Another problem would occur if the PC was left to suspend automatically with more than one user still logged in (i.e. more than one session). Although Light Locker would display the LightDM GTK+ Greeter screen upon resuming from suspension, and users could select their username from the pull-down list and enter their password, the LightDM GTK+ Greeter screen would remain on display and it would no longer be possible to re-enter a password (although it was still possible to select users from the pull-down list of users, and to select ‘Suspend’, ‘Restart…’ and ‘Shutdown…’ from the pull-down power menu). However, if users suspended the PC manually by selecting ‘Logout’ > ‘Lock Screen’ from the Lubuntu Menu, upon waking/resuming it was possible to enter their password on the LightDM GTK+ Greeter screen to return to their Desktop.

In this article I explain what I did to try and rectify these problems.

By the way, note that hibernation is disabled by default in Lubuntu 17.10 and you may need to make further changes if you want to enable hibernation as well. For example, does the PC have a swap partition, and is it large enough to enable hibernation? Also see the article: How to Enable Hibernate in Ubuntu 17.10 for possible help.

Modifications

The package light-locker-settings was not installed in Lubuntu 17.10. Do not install it. If it happens to be installed do not use ‘Preferences’ > ‘Light Locker Settings’, as it makes the Exec entry in the user’s light-locker.desktop file just ‘Exec=‘ or ‘Exec=light-locker‘. In fact, having installed light-locker-settings manually to check what could be configured via its GUI, I uninstalled it in order to stop anyone using it. (Under ‘Screensaver’, the Light Locker Settings GUI displays the following message: ‘Your screensaver settings are managed by Xfce Power Manager.’ and there is a button ‘Open’ to click on to launch the Xfce Power Manager settings GUI.) Presumably this was why it was not included when Lubuntu 17.10 was first installed to the HDD.

1.  I removed any light-locker.desktop files of individual users, leaving only the system-wide file:

$ sudo rm /home/*/.config/autostart/light-locker.desktop
$ sudo updatedb
$ locate light-locker.desktop
/etc/xdg/autostart/light-locker.desktop

2.  I edited the system-wide light-locker.desktop file to contain the following command to execute Light Locker:

$ grep Exec /etc/xdg/autostart/light-locker.desktop
Exec=light-locker --lock-after-screensaver=0 --no-lock-on-suspend --no-lock-on-lid --no-idle-hint

3.  I created the Bash script file /lib/systemd/system-sleep/hang-fix for systemd to run when suspending and resuming from suspension, with the permissions shown:

#!/bin/sh
case "$1" in
    pre|suspend|hibernate)
        date | tr -d '\n' >> /home/fitzcarraldo/sleep.log
        echo " going to sleep." >> /home/fitzcarraldo/sleep.log
        chvt 1
        loginctl unlock-sessions
    ;;
    post|resume|thaw)
        date | tr -d '\n' >> /home/fitzcarraldo/sleep.log
        echo " waking from sleep." >> /home/fitzcarraldo/sleep.log
        loginctl lock-sessions
        chvt 7
    ;;
    *)
        exit $NA
    ;;
esac
exit 0

$ sudo chmod 755 /lib/systemd/system-sleep/hang-fix
$ ls -la /lib/systemd/system-sleep/hang-fix
-rwxr-xr-x 1 root root 581 Apr 14 08:09 /lib/systemd/system-sleep/hang-fix

The above script is a hack to get around the problem of Light Locker resuming and apparently not knowing which session to unlock. I used the loginctl commands in this script rather than the Xfce Power Manager suspend options and Light Locker options such as ‘--late-locking‘ and ‘--lock-on-suspend‘ because I found that the Light Locker options and the Xfce Power Manager options did not fix the problem.

4.  I created two files for Polkit (to cover all Polkit versions to date) with the permissions as shown below.

4.1  The file /etc/polkit-1/rules.d/85-suspend.rules with the following contents:

polkit.addRule(function(action, subject) {
    if (action.id == "org.freedesktop.login1.suspend" ||
        action.id == "org.freedesktop.login1.suspend-multiple-sessions" ||
        action.id == "org.freedesktop.login1.hibernate" ||
        action.id == "org.freedesktop.login1.hibernate-multiple-sessions")
    {
        return polkit.Result.YES;
    }
});

If you do not have a swap partition large enough to enable hibernation, or you do not want to allow the PC to hibernate, use the following instead of the above:

polkit.addRule(function(action, subject) {
    if (action.id == "org.freedesktop.login1.suspend" ||
        action.id == "org.freedesktop.login1.suspend-multiple-sessions")
    {
        return polkit.Result.YES;
    }
});

$ sudo chmod 755 /etc/polkit-1/rules.d
$ sudo chmod 644 /etc/polkit-1/rules.d/85-suspend.rules
$ ls -la /etc/polkit-1/rules.d/85-suspend.rules
-rw-r--r-- 1 root root 359 Apr 19 22:14 /etc/polkit-1/rules.d/85-suspend.rules

4.2  The file /var/lib/polkit-1/localauthority/50-local.d/50-enable-suspend-on-lockscreen.pkla with the following contents:

[Allow suspending with lock screen]
Identity=unix-user:*
Action=org.freedesktop.login1.suspend;org.freedesktop.login1.suspend-multiple-sessions;org.freedesktop.login1.hibernate;org.freedesktop.login1.hibernate-multiple-sessions
ResultAny=yes
ResultInactive=yes
ResultActive=yes

If you do not have a swap partition large enough to enable hibernation, or you do not want to allow the PC to hibernate, use the following instead of the above:

[Allow suspending with lock screen]
Identity=unix-user:*
Action=org.freedesktop.login1.suspend;org.freedesktop.login1.suspend-multiple-sessions
ResultAny=yes
ResultInactive=yes
ResultActive=yes

$ sudo chmod 644 /var/lib/polkit-1/localauthority/50-local.d/50-enable-suspend-on-lockscreen.pkla
$ sudo ls -la /var/lib/polkit-1/localauthority/50-local.d/50-enable-suspend-on-lockscreen.pkla
-rw-r--r-- 1 root root 191 Apr 20 10:01 /var/lib/polkit-1/localauthority/50-local.d/50-enable-suspend-on-lockscreen.pkla

The above files are intended to get rid of the following error messages in a pop-up window and pop-up notification ballon, respectively, that prevent the OS from suspending automatically:

Authentication
Authentication is required for suspending
the system while other users are logged in.

Power Manager
GDBus.Error:org.freedesktop.DBus.Error.NoReply:
Method call timed out

By the way, the version of Polkit installed currently is 0.105:

$ pkaction --version
pkaction version 0.105

5.  I added all users to the users group (although I do not think this is essential):

$ sudo usermod -a -G users fitzcarraldo
$ sudo usermod -a -G users molly
$ sudo usermod -a -G users aquilino
$ sudo usermod -a -G users cholo
$ sudo usermod -a -G users paul

6.  I made sure the XScreenSaver settings for each user are as follows:

XScreenSaver (‘Preferences’ > ‘Screensaver’)

The ‘Display Modes’ tab has:

  • ‘Mode: Disable Screen Saver’

The ‘Advanced’ tab has everything unticked on it except for:

7.  I made sure the Xfce Power Manager settings for each user are as follows:

Xfce Power Manager (‘Preferences’ > ‘Power Manager’)

The ‘General’ tab has:
Buttons

  • When power button is pressed: Ask
  • When sleep button is pressed: Do nothing
  • When hibernate button is pressed: Do nothing

Appearance

  • Show notifications is ticked
  • Show system tray icon is ticked

The ‘System’ tab has:
System power saving

  • System sleep mode: Suspend
  • When inactive for 15 Minutes (You can make the number of minutes different for each user, if you want.)

The ‘Display’ tab has:
Display power management settings

  • ‘Handle display power management’ is ticked
  • Blank after: 5 Minutes
  • Put to sleep after: Never
  • Switch off after: Never

The ‘Security’ tab has:
Light Locker

  • Automatically lock the session: Never
  • Delay locking after screensaver for: ‘1 Seconds’ is greyed out
  • ‘Lock screen when system is going for sleep’ is not ticked

8.  I made sure the ‘Default Applications for LXSession’ settings for each user are as follows:

Select ‘Preferences’ > ‘Default Applications for LXSession’, click on ‘Autostart’ and untick ‘XScreenSaver’ if it is ticked. ‘Power Manager’ and ‘Screen Locker’ should already be ticked, so tick them if they are not. I left ‘PolicyKit Handler’ and ‘PolicyKit Authentication Agent’ unticked (Lubuntu 17.10 uses Polkit, the successor to PolicyKit).

9.  Although Lubuntu 17.10 does not use GNOME, I found that gsettings is installed. I did the following just in case, although I believe it is irrelevant in this particular case:

$ gsettings --version
2.54.1
$ gsettings set org.gnome.desktop.screensaver ubuntu-lock-on-suspend 'false'
$ gsettings get org.gnome.desktop.screensaver ubuntu-lock-on-suspend
false
$ gsettings set org.gnome.desktop.screensaver lock-enabled 'false'
$ gsettings get org.gnome.desktop.screensaver lock-enabled
false

Conclusion

After doing all the above, upon resuming from Suspend-to-RAM on most, but not all, occasions it is now possible to select any username on the LightDM GTK+ Greeter screen, enter that user’s password and successfully display the user’s Desktop. The LightDM GTK+ Greeter screen no longer hangs/freezes every time.

When more than one user is logged in (i.e. there is more than one session), the PC will suspend automatically if there is no user activity in a particular session during the configured timeout period for that session. Pressing a key on the USB keyboard will then wake the PC and display the LightDM GTK+ Greeter screen. The desired username can then be selected and the corresponding password entered. The following is an example of the sort of thing that can happen:

  • User fitzcarraldo (timeout configured as 30 minutes) logs in to his account at 09:00 and uses the PC until he locks his session manually (Ctrl+Alt+L) at 09:11.
  • User paul (timeout configured as 15 minutes) logs in to his account at 09:15 and uses the PC until he locks his session manually at 09:23.
  • User molly (timeout configured as 45 minutes) logs in to her account at 09:25 and uses the PC for several hours.
  • At 09:38, while user molly is using the PC, the PC automatically suspends to RAM (15 minutes after user paul stopped using his session). User molly has to wake the PC from suspension. Nothing is lost.
  • At 09:41, while user molly is using the PC, the PC automatically suspends to RAM (30 minutes after user fitzcarraldo stopped using his session). User molly has to wake the PC from suspension. Nothing is lost.

To avoid scenarios such as the above, if a user does not need the session any longer it is better to log out rather than leave the session in existence.

Backing up users’ home directories in a Linux installation that uses systemd

This is to explain how I configured Lubuntu 17.10 on my family’s PC (single seat; multiple user accounts) to backup all users’ files to a permanently-connected external USB HDD. I wanted a basic solution that would backup automatically every user’s home directory at shutdown but not when rebooting, and would do this whichever user happens to be using the PC. We have no need to archive older versions of the same file, so overwriting a file on the external USB HDD with a newer version of that file from the PC’s HDD is fine. However, we do not want files on the external USB HDD to be deleted if the corresponding files have been deleted from the PC’s HDD. Additionally, I want a time-stamped record of the backup process to be logged to a file in my home directory so I can check periodically what has been happening. As explained in my previous post, two files are used to achieve all these things:

  • a Bash script to a) determine whether the system is being rebooted, b) remount the external USB HDD on a suitable mount point, c) copy the files to the external USB HDD, and d) write to the log file;
  • a systemd unit file to launch the Bash script.

The two files are described below.

By the way, I also tried using systemd-inhibit in this case, and it did not work. Looking at the manual page for systemd-inhibit, it could be used to execute a program (the example given is ‘systemd-inhibit wodim foobar.iso‘), however I found that systemd-inhibit did not prevent systemd from shutting down the machine before the backup Bash script had run to completion.

Bash script

I created a file /usr/local/sbin/backup_home_directories.sh owned by the root user, with the following permissions and contents:

fitzcarraldo@aspirexc600:~$ ls -la /usr/local/sbin/backup_home_directories.sh
-rwxr-xr-x 1 root root 2570 Jan  8 20:37 /usr/local/sbin/backup_home_directories.sh
#!/bin/bash

# This script backs up to an external USB HDD (NTFS) labelled "FREECOM HDD" the contents of the home directories
# of the users of this Lubuntu 17.10 installation if the system is shutting down but not rebooting.
# It is launched by a systemd service /etc/systemd/system/backup-to-usb-hdd.service.

# Find out if the system is rebooting (as opposed to being shut down):
REBOOT=$( systemctl list-jobs | egrep -q 'reboot.target.*start' && echo "rebooting" || echo "not_rebooting" )
if [ $REBOOT = "not_rebooting" ]; then
# Only execute the following steps if the system is shutting down but not rebooting:
    # Clean up if the backup did not complete last time:
    umount /media/usbhdd 2>/dev/null # Make sure you enter this line correctly.
    rm -rf /media/usbhdd/* # Make sure you enter this line correctly.
    # Unmount the external USB HDD if mounted by udisks2 with the logged-in username in the path:
    umount /media/*/FREECOM\ HDD 2>/dev/null
    # Find out the USB HDD device:
    DEVICE=$( blkid | grep "FREECOM\ HDD" | cut -d ":" -f1 )
    # Create a suitable mount point if it does not already exist, and mount the device on it: 
    mkdir /media/usbhdd 2>/dev/null
    mount -t ntfs-3g $DEVICE /media/usbhdd 2>/dev/null
    # Create the backup directory on the USB HDD if it does not already exist:
    mkdir /media/usbhdd/Lubuntu_home_folders_backup 2>/dev/null
    # Backup recursively all the home directories of all the users, and add a time-stamped summary to the log file: 
    echo "********** Backing up Acer Aspire XC600 users' home directories **********" >> /home/fitzcarraldo/backup.log
    date >> /home/fitzcarraldo/backup.log
    # Log username of user shutting down the PC (may not be this user if Switch User was used):
    echo -ne "User who shutdown PC (may not be this user if Switch User has been used): " >> /home/fitzcarraldo/backup.log
    last | cut -d " " -f1 | head -1 >> /home/fitzcarraldo/backup.log
    sleep 2s
    # To backup the directories and files I prefer to use the following cp command rather than rsync:
    cp --recursive --update --preserve=all --no-dereference --force /home/ /media/usbhdd/Lubuntu_home_folders_backup 2>> /home/fitzcarraldo/backup.log
    echo "Copying completed" >> /home/fitzcarraldo/backup.log
    date >> /home/fitzcarraldo/backup.log
    echo "********** Backup completed **********" >> /home/fitzcarraldo/backup.log
    cp /home/fitzcarraldo/backup.log /media/usbhdd/Lubuntu_home_folders_backup/home/fitzcarraldo/
    # Unmount the USB HDD so that udisks2 can subsequently re-mount it with the user's username in the path:  
    umount /media/usbhdd
fi
exit 0

The Bash script unmounts the external USB HDD and mounts it to /media/usbhdd before performing a backup. This is done because the Udisks daemon (udisksd) automounts the HDD at login to a mountpoint /media/<username>/FREECOM HDD  (e.g. ‘/media/fitzcarraldo/FREECOM HDD‘ when I log in, ‘/media/claudia/FREECOM HDD‘ when user claudia logs in, and so on).

systemd unit file

I created a file /etc/systemd/system/backup-to-usb-hdd.service owned by the root user, with the following permissions and contents:

fitzcarraldo@aspirexc600:~$ ls -la /etc/systemd/system/backup-to-usb-hdd.service 
-rw-r--r-- 1 root root 274 Jan  8 17:51 /etc/systemd/system/backup-to-usb-hdd.service
[Unit]
Description=Backup home directories of all users to USB HDD
DefaultDependencies=no
Before=shutdown.target halt.target
RequiresMountsFor=/home

[Service]
Type=oneshot
ExecStart=/usr/local/sbin/backup_home_directories.sh

[Install]
WantedBy=halt.target shutdown.target

Then I enabled the unit file as follows:

fitzcarraldo@aspirexc600:~$ sudo systemctl enable backup-to-usb-hdd.service
Created symlink /etc/systemd/system/halt.target.wants/backup-to-usb-hdd.service → /etc/systemd/system/backup-to-usb-hdd.service.
Created symlink /etc/systemd/system/shutdown.target.wants/backup-to-usb-hdd.service → /etc/systemd/system/backup-to-usb-hdd.service.
fitzcarraldo@aspirexc600:~$

Reboot (or shutdown and restart) to launch it.

The log file

The log file /home/fitzcarraldo/backup.log looked like the following after shutting down a couple of times:

********** Backing up Acer Aspire XC600 users' home directories **********
Mon  8 Jan 21:07:05 GMT 2018
User who shutdown PC (may not be this user if Switch User has been used): fitzcarraldo
Copying completed
Mon  8 Jan 21:07:32 GMT 2018
********** Backup completed **********
********** Backing up Acer Aspire XC600 users' home directories **********
Mon  8 Jan 21:15:31 GMT 2018
User who shutdown PC (may not be this user if Switch User has been used): fitzcarraldo
Copying completed
Mon  8 Jan 21:15:48 GMT 2018
********** Backup completed **********

Whenever the system is rebooted by any user, nothing is appended to the log file. As desired, entries are only appended to the log file when the system is shutdown by any user.

Manually initiated backups

An added benefit is that any user in the sudo group can run the Bash script from the command line at any time to backup without having to shutdown the PC, as illustrated below:

claudia@aspirexc600:~$ cat /home/fitzcarraldo/backup.log 
********** Backing up Acer Aspire XC600 users' home directories **********
Mon  8 Jan 21:07:05 GMT 2018
User who shutdown PC (may not be this user if Switch User has been used): fitzcarraldo
Copying completed
Mon  8 Jan 21:07:32 GMT 2018
********** Backup completed **********
********** Backing up Acer Aspire XC600 users' home directories **********
Mon  8 Jan 21:15:31 GMT 2018
User who shutdown PC (may not be this user if Switch User has been used): fitzcarraldo
Copying completed
Mon  8 Jan 21:15:48 GMT 2018
********** Backup completed **********
claudia@aspirexc600:~$ date && sudo backup_home_directories.sh
Tue  9 Jan 01:57:50 GMT 2018
[sudo] password for claudia:
claudia@aspirexc600:~$ cat /home/fitzcarraldo/backup.log 
********** Backing up Acer Aspire XC600 users' home directories **********
Mon  8 Jan 21:07:05 GMT 2018
User who shutdown PC (may not be this user if Switch User has been used): fitzcarraldo
Copying completed
Mon  8 Jan 21:07:32 GMT 2018
********** Backup completed **********
********** Backing up Acer Aspire XC600 users' home directories **********
Mon  8 Jan 21:15:31 GMT 2018
User who shutdown PC (may not be this user if Switch User has been used): fitzcarraldo
Copying completed
Mon  8 Jan 21:15:48 GMT 2018
********** Backup completed **********
********** Backing up Acer Aspire XC600 users' home directories **********
Tue  9 Jan 01:57:54 GMT 2018
User who shutdown PC (may not be this user if Switch User has been used): claudia
Copying completed
Tue  9 Jan 01:58:10 GMT 2018
********** Backup completed **********
claudia@aspirexc600:~$

Running a shell script at shutdown only (not at reboot) – a comparison between OpenRC and systemd

Gentoo Linux on my laptops uses OpenRC with SysVinit, whereas Lubuntu 17.10 on my family’s PC uses systemd. I have had to configure both Linux distributions to run a backup job at shutdown, so I thought it would be interesting to summarise the two approaches.

OpenRC

Create a Bash script /etc/local.d/10-run_on_shutdown.stop with the following contents:

#!/bin/bash
if [ `who -r | awk '{print $2}'` = "0" ]; then
    ########################################################################
    # Put Bash commands here to be executed on shutdown but not on reboot. #
    # For example, backup home directories to an external USB HDD.         #
    ########################################################################
fi

From now on the script will run to completion when you shutdown the machine, but not when you reboot it.

systemd

1. Create a Bash script /usr/local/sbin/run_on_shutdown.sh with the following contents:

#!/bin/bash
REBOOT=$( systemctl list-jobs | egrep -q 'reboot.target.*start' && echo "rebooting" || echo "not_rebooting" )
if [ $REBOOT = "not_rebooting" ]; then
    ########################################################################
    # Put Bash commands here to be executed on shutdown but not on reboot. #
    # For example, backup home directories to an external USB HDD.         #
    ########################################################################
fi

2. Create a unit file /etc/systemd/system/run_on_shutdown.service with the following contents:

[Unit]
Description=Run a Bash script at shutdown
DefaultDependencies=no
Before=shutdown.target halt.target
# If your script requires any mounted directories, add them below: 
RequiresMountsFor=/home

[Service]
Type=oneshot
ExecStart=/usr/local/sbin/run_on_shutdown.sh

[Install]
WantedBy=halt.target shutdown.target

I have assumed the Bash script is to backup /home, so change the directory list in ‘RequiresMountsFor=‘ if the script necessitates that other directories are still mounted – see ‘man systemd.unit‘ for details.

3. Enable the unit file and start the service as follows:

user $ sudo systemctl enable run_on_shutdown.service
user $ sudo reboot

From now on, the script will run to completion when you shutdown the machine, but not when you reboot it.

Notes on the systemd solution:

There are plenty of posts on the Web suggesting how to run a script at shutdown in installations that use systemd, but the approaches either do not work in my case or they do not discriminate between shutting down and rebooting. For example, if you are wondering why I do not use ‘Conflicts=reboot.target‘ in the unit file, I found it does not prevent the Bash script from being launched when the system is rebooted (see the entry for ‘Conflicts=‘ in ‘man systemd.unit‘ for the functionality). If you are wondering why I do not simply place a script in /lib/systemd/system-shutdown/, it is because scripts in that directory are launched late in the shutdown process, after file systems have been mounted read-only. And if you are wondering why the Bash script tests if the system is rebooting (as distinct from shutting down) rather than the unit file being configured to do that, it is because the systemd shutdown target is active in any type of system termination, be it rebooting or halting, and it therefore does not help in discriminating between the termination types (see ‘man systemd.special‘). I tried several approaches in the unit file to see if it could be made to launch a Bash script when shutting down but not when rebooting, but the only solution that works for me in the Lubuntu 17.10 installation on my family’s PC uses the two files listed above working in conjunction with each other.

Furthermore, of all the unit files I found on the Web that actually make systemd launch a Bash script when a user initiates shutdown, only one of them prevents systemd from shutting down the machine before a time-consuming script has run to completion (for example a script to backup to an external HDD). I also tried using systemd-inhibit in this case, and it did not work. Looking at the manual page for systemd-inhibit, it could be used to execute a program (the example given is ‘systemd-inhibit wodim foobar.iso‘), however I found that systemd-inhibit did not prevent systemd from shutting down the machine before a Bash script to backup a single-seat, multi-user installation had run to completion.

Some background reading

  1. Easy Systemd Startup and Shutdown Scripts for Ubuntu 16.04 and Mint 18
  2. Stack Exchange Super User : How do I run a script before everything else on shutdown with systemd?
  3. Stack Overflow : how can a systemd controlled service distinguish between shutdown and reboot?
  4. Unix & Linux Stack Exchange : Systemd : How to execute script at shutdown only (not at reboot)

A method of ‘masking’ an OpenRC service (NetworkManager, in this case)

A Gentoo Linux user with an installation using OpenRC recently asked in the Gentoo Forums how to either a) disable NetworkManager so that it would not interfere with his netifrc configuration to give his installation a static IP address, or b) configure NetworkManager to use a static IP address (see the thread NetworkManager and static IP [SOLVED! THANKYOU]). In the end he solved the problem by uninstalling NetworkManager, the cleanest solution in his case given that his desktop machine is always in the same location and he does not need the features NetworkManager provides.

Now, although I use NetworkManager instead of netifrc, what intrigued me is that disabling the NetworkManager service using the standard command below does not stop the NetworkManager init script from running at boot-up:

root # rc-update delete NetworkManager default

Despite using the above command, following a reboot the NetworkManager service is still started and becomes active, and the NetworkManager daemon is running. Web browsers and other applications requiring network access still work. In order to stop the service running immediately so that his netifrc static IP address configuration could work, the aforementioned Gentoo user had to stop the NetworkManager service as follows:

root # /etc/init.d/NetworkManager stop

(The command ‘rc-service NetworkManager stop‘ does the same thing.)

The behaviour is the same on my laptop running Gentoo with OpenRC 0.22.4 and NetworkManager installed by networkmanager-1.4.0-r1 ebuild (with the upstream patch and necessary edit to the init script mentioned in Gentoo Bug Report No. 595806 – net-misc/networkmanager-1.4.0-r1[consolekit]: doesn’t automatically activate connections marked with "Automatically connect to this network when it’s available").

So two questions arose: What launches the NetworkManager init script when it has not been added to a runlevel? What needs to be done to stop this from happening? My curiosity was piqued.

As it happens, a somewhat similar situation exists when using systemd rather than OpenRC, as explained in Arch Linux Forums thread [SOLVED] NetworkManager auto restart even though I stop it. and Red Hat Bugzilla Report No. 815243 – Even though NetworkManager was manually stopped, it gets restarted automatically via D-Bus, although those were primarily concerned with how to prevent NetworkManager being restarted during the same session, i.e. without having rebooted.

The following systemd commands are needed to stop immediately the NetworkManager service and keep it from being restarted subsequently during the current session and after rebooting:

root # systemctl mask NetworkManager
root # systemctl stop NetworkManager
root # systemctl disable NetworkManager

Unfortunately there is no equivalent mask command for an OpenRC service. The equivalent OpenRC commands for the second and third commands above are:

root # rc-service NetworkManager stop
root # rc-update delete NetworkManager default

However, as I pointed out earlier, for some reason the latter command does not stop OpenRC running the NetworkManager init script at boot.

I wondered how I could ‘mask’ the NetworkManager service in OpenRC. I asked myself what the systemd mask command actually does. Well, it simply creates a symlink from /etc/systemd/system/NetworkManager.service to /dev/null so that there is no longer a real unit file for systemd to use, and therefore systemd can no longer launch the service. So why not do something similar in OpenRC. I hit upon the idea of telling the NetworkManager init script it needs a non-existent service in order to start, thus preventing OpenRC from starting the NetworkManager service:

root # echo 'rc_need="non-existent_service"' >> /etc/conf.d/NetworkManager # (Or just edit the file manually.)

That is all there is to it. When booting, OpenRC now displays the messages shown below:

* ERROR: NetworkManager needs service(s) non-existent_service
* ERROR: cannot start netmount as NetworkManager would not start
* ERROR: cannot start samba as NetworkManager would not start

As shown below, now the service is not started, so the NetworkManager daemon is never launched:

root # rc-status
Runlevel: default
 dbus                                                  [  started  ]
 syslog-ng                                             [  started  ]
 consolekit                                            [  started  ]
 netmount                                              [  stopped  ]
 cupsd                                                 [  started  ]
 samba                                                 [  stopped  ]
 cronie                                                [  started  ]
 clamd                                                 [  started  ]
 bluetooth                                             [  started  ]
 xdm                                                   [  started  ]
 cups-browsed                                          [  started  ]
 sshd                                                  [  started  ]
 local                                                 [  started  ]
Dynamic Runlevel: hotplugged
Dynamic Runlevel: needed/wanted
 modules-load                                          [  started  ]
 xdm-setup                                             [  started  ]
 avahi-daemon                                          [  started  ]
Dynamic Runlevel: manual
root # ps -ef | grep -v grep | grep -i network
root #

As expected, given that the netmount service and samba service depend on the NetworkManager service starting, neither of those services were able to start either.

Furthermore, because I masked the service, if I attempt to start it manually:

root # rc-service NetworkManager restart
 * ERROR: NetworkManager needs service(s) non-existent_service

To unmask the service in OpenRC, all that is needed is:

root # sed -i '/rc_need="non-existent_service"/d' /etc/conf.d/NetworkManager # (Or just edit the file manually.)

Note that, instead of “non-existent_service” I could have written “fubar”, “null” or any other string that is not the name of an actual service. But “non-existent_service” is more meaningful and less likely to confuse me when viewing system messages and contents of the service configuration file.

In summary…

Why does OpenRC run the NetworkManager service init script when it is not in any runlevel?

I have no idea!

I wondered if the D-Bus service does it. The Arch Wiki article on NetworkManager claims this is the case (see the section titled Disable NetworkManager). However, my attempts at preventing D-Bus doing anything to NetworkManager did not stop the NetworkManager init script from being run at boot. I deleted /etc/dbus-1/system.d/org.freedesktop.NetworkManager.conf and /etc/dbus-1/system.d/nm-dispatcher.conf but that did not help. Neither did creating an appropriate /etc/dbus-1/system.d/org.freedesktop.NetworkManager.conf or /etc/dbus-1/system-local.conf. There is no /usr/share/dbus-1/system-services/org.freedesktop.NetworkManager.service file in my Gentoo installation using OpenRC, but creating one did not help either. So, if you know what runs the OpenRC NetworkManager init script when it is not in any runlevel, please post a comment.

Anyway, I now know how to prevent it happening, so I have satisfied my curiosity. Below I list the commands I actually used in a Gentoo Linux installation (amd64, OpenRC) and a Sabayon Linux installation (~amd64, systemd) to check the functionality.

OpenRC

The following two (optionally three) commands are needed to stop immediately the NetworkManager service and prevent it being restarted subsequently during this session and after rebooting:

root # rc-service NetworkManager stop
root # echo 'rc_need="non-existent_service"' >> /etc/conf.d/NetworkManager
root # rc-update del NetworkManager default # (Optional.)

The following two (optionally three) commands are needed to unmask the NetworkManager service and start it immediately, and make it start automatically after rebooting:

root # sed -i '/rc_need="non-existent_service"/d' /etc/conf.d/NetworkManager
root # rc-service NetworkManager restart
root # rc-update add NetworkManager default # Only needed if I earlier deleted the service from the default runlevel.

systemd

The following three commands are needed to stop immediately the NetworkManager service and prevent it being restarted subsequently during this session and after rebooting:

root # systemctl mask NetworkManager
root # systemctl stop NetworkManager
root # systemctl disable NetworkManager

The following three systemd commands are needed to unmask the NetworkManager service and start it immediately, and also make it start automatically after rebooting:

root # systemctl unmask NetworkManager
root # systemctl enable NetworkManager
root # systemctl start NetworkManager

Installing and configuring the CUPS-PDF virtual printer driver

Some applications, such as LibreOffice, have built-in support for exporting their output to PDF files. For applications without built-in support for creating PDF files there may already be an installed ‘Print to File (PDF)’ driver in your installation that you can use. However, the Print to File (PDF) option does not appear in the list of available printers in all applications. Fortunately, CUPS has a driver named CUPS-PDF which you can install to create a virtual printer that will produce PDF files.

I install the package net-print/cups-pdf and use the CUPS Printer Manager in a browser to set up a virtual printer to ‘print’ PDF files. I use the driver in conjunction with a shell script that calls a utility to display a ‘Save As’ dialogue box so the user can specify the directory and name of the PDF file.

KDialog (KDE/Qt) and Zenity (GTK+) are two well-known dialogue box tools for use in shell scripts (see, for example, the Linux Magazine article Adding graphic elements to your scripts with Zenity and KDialog). However, although I use KDE on my main laptop, I was unable to get KDialog working properly in a shell script launched by the CUPS PDF driver, so I resorted to using Zenity, which I found simple to use and reliable. My shell script using Zenity is listed further down.

Although Zenity has performed this job perfectly for me in all releases of KDE since 2007, it rankled that I could not get KDialog to do the job. However, a couple of Gentoo users were able to use KDialog successfully with the CUPS PDF driver, each with a different approach to the other, but their approaches both consisted of two shell scripts. In contrast, a solution using Zenity uses only one shell script. You can see the KDialog solutions by the two users (Havin_it and sicvolo) in Gentoo Forums thread [TIP] CUPS-PDF “Save As” with kdialog. I was determined to have a single shell script using KDialog, and was able to conflate sicvolo‘s two-script solution. My thanks go to him for his clever code in his two shell scripts, as I would never have worked it out myself. My single shell script using KDialog is listed further down.

First I will explain how to install the CUPS PDF driver package, then how to use the CUPS Printer Manager to install the virtual printer, and finally how to use a shell script with either Zenity or KDialog in order to display a graphical dialogue box prompting you to specify the directory and file name for the PDF file to be created. I use Gentoo Linux, but the procedure will be similar in other distributions (package manager commands excepted).

1.0  Installation of the cups-pdf driver and virtual printer

1.1  Install the cups-pdf package:

# emerge cups-pdf

1.2  Launch a Web browser and enter http://localhost:631/ in the Address bar to display the CUPS Printer Manager.

1.3  Click on ‘Administration’ to call up the Administration page, then click ‘Add Printer’. If prompted, enter the username ‘root’ (without the quotes) and the root user’s password.

1.4  Select ‘CUPS-PDF (Virtual PDF Printer)’ in the list of local printers, and click ‘Continue’.

1.5  Enter a name, decription and location for the virtual printer. For example, I entered ‘Virtual_PDF_Printer’, ‘Virtual PDF Printer’ and ‘Mesh Edge DX’ (without the quotes), respectively. Then click ‘Continue’.

1.6  Select ‘Generic’ in the ‘Make:’ box, and click ‘Continue’.

1.7  Select ‘Generic CUPS-PDF Printer (w/ options) (en)’ in the ‘Model:’ box, and click ‘Add Printer’. The virtual printer should now be available for you to use.

1.8  When you come to print from an application, if you select Virtual_PDF_Printer from the list of available printers the PDF file will be saved in the directory /var/spool/cups-pdf/<your username>/. Note that the directory will be created automatically the first time you ‘print’ to PDF.

1.9  Optionally, you could create a shortcut (Desktop Config File) on your Desktop to open the directory mentioned in Step 1.8 above.

1.10 Optionally, instead of Step 1.9 you could edit the file /etc/cups/cups-pdf.conf as root user to get cups-pdf to ‘print’ PDF documents to your Desktop instead of in /var/spool/cups-pdf/<your username>/, by changing the line:

#Out /var/spool/cups-pdf/${USER}

to:

Out ${HOME}/Desktop


2.0  How to display a dialog box prompting for the directory and file name of the PDF file

If you prefer to be prompted for a file name so that you can save the PDF file wherever you want and give it any name you want, perform the steps below instead of Steps 1.9 or 1.10 above. Either perform the steps in 2.1 (Zenity) or the steps in 2.2 (KDialog). Then perform the steps in 2.3, which apply in both cases.

2.1   Zenity (GTK+)

2.1.1   Install Zenity:

# emerge zenity

2.1.2   Check it is installed:

# eix -I zenity
[I] gnome-extra/zenity
Available versions: 3.12.1 {debug libnotify test +webkit}
Installed versions: 3.12.1(13:49:47 04/12/14)(libnotify webkit -debug -test)
Homepage: https://wiki.gnome.org/Projects/Zenity
Description: Tool to display dialogs from the commandline and shell scripts

2.1.3   Using a text editor, create the following shell script in your home directory and give it a meaningful name, such as cups-pdf_script.sh:

#!/bin/bash
CURRENT_PDF="${1}"
CURRENT_USER="${2}"
DISPLAY=:0.0
export DISPLAY
XAUTHORITY=/home/${CURRENT_USER}/.Xauthority
export XAUTHORITY
PDFNAME=$(zenity --file-selection --save --confirm-overwrite)
mv "$CURRENT_PDF" "$PDFNAME"

2.2   KDialog (KDE/Qt)

2.2.1   Install KDialog:

# emerge kde-base/kdialog

2.2.2   Check it is installed:

# eix -I kde-base/kdialog
[I] kde-base/kdialog
Available versions: (4) 4.12.5(4/4.12) (~)4.14.2(4/4.14) (~)4.14.3(4/4.14)
{aqua debug}
Installed versions: 4.14.3(4)(00:56:36 04/12/14)(-aqua -debug)
Homepage: http://www.kde.org/
Description: KDialog can be used to show nice dialog boxes from shell scripts

2.2.3   Using a text editor, create the following shell script in your home directory and give it a meaningful name such as cups-pdf_script.sh:

#!/bin/bash

get_dbus()
{
if [ -z $1 ]; then
    echo "specify user" >> $HOME/cups-pdf_script.log
    return 1
fi
# Search these processes for the session variable (they are run as the current user and have the DBUS session variable set)
compatiblePrograms=( kdeinit kded4 pulseaudio trackerd )

# Attempt to get a program pid
for index in ${compatiblePrograms[@]}; do
   PID=$(ps -ef | grep $1 | grep ${index} | head -1 | awk '{print $2}')
   if [[ "${PID}" != "" ]]; then
      break
   fi
done
if [[ "${PID}" == "" ]]; then
   echo "Could not detect active login session" >> $HOME/cups-pdf_script.log
   return 1
fi
QUERY_ENVIRON="$(tr '\0' '\n' < /proc/${PID}/environ | grep "DBUS_SESSION_BUS_ADDRESS" | cut -d "=" -f 2-)"
if [[ "${QUERY_ENVIRON}" != "" ]]; then
#   echo ${QUERY_ENVIRON} >> $HOME/cups-pdf_script.log
   return 0
else
   echo "Could not find dbus session ID in user environment." >> $HOME/cups-pdf_script.log
   return 1
fi
}

CURRENT_PDF="$1"
CURRENT_USER="$2"

export DISPLAY=:0
export XAUTHORITY=/home/${CURRENT_USER}/.Xauthority
export HOME=/home/${CURRENT_USER}/
CONFIG_FILE="/home/${CURRENT_USER}/.pdf-writer.conf"
CANCELLED="No"

date > $HOME/cups-pdf_script.log

get_dbus ${CURRENT_USER}
if [ $? -eq 0 ]; then
   export DBUS_SESSION_BUS_ADDRESS=${QUERY_ENVIRON}
   while [ True ]; do
      CURDATE=$(/bin/date +%Y%m%d)
      CURNAME=$(/bin/cat "$CONFIG_FILE")
      BASENAME=$(basename $CURRENT_PDF)
      FILENAME=$(/usr/bin/kdialog --getsavefilename "$CURNAME$CURDATE-" "*.pdf" --title="Save PDF")
      if [ $? -eq 1 ]; then
         CANCELLED="Yes"
         break
      fi
      echo $FILENAME
      if [ ! "$FILENAME" = "" ]; then
         if [ -e "$FILENAME" ]; then
            /usr/bin/kdialog --warningcontinuecancel "File already exists"
            if [ $? -eq 1 ]; then
               continue;
            fi
         fi
         FILENAME=$(echo $FILENAME.pdf | sed -re "s/(\.pdf)+$/.pdf/g")
         break;
      else
         /usr/bin/kdialog --error "You must select a file or hit Cancel."
      fi
      break
   done
   if [ "${CANCELLED}" == "No" ]; then
      /bin/cp "${CURRENT_PDF}" "${FILENAME}"
      okular "${FILENAME}" &
   fi
   /bin/rm "${CURRENT_PDF}"
   echo "No errors encountered." >> $HOME/cups-pdf_script.log
   exit 0
else
   /bin/rm "${CURRENT_PDF}"
   echo "Errors encountered." >> $HOME/cups-pdf_script.log
   exit 1
fi

2.3   Whichever of the above two options (Zenity or KDialog) you chose, do the following:

2.3.1   Make the shell script file executable:

# chmod +x /home/<your username>/cups-pdf_script.sh

2.3.2   Edit the file /etc/cups/cups-pdf.conf, find the line starting with ‘#PostProcessing‘, and change it to:

PostProcessing /home/<your username>/cups-pdf_script.sh

2.3.3   Restart CUPS:

# /etc/init.d/cupsd restart # If your installation uses OpenRC.

# systemctl restart cups.service # If your installation uses systemd.

Now, when you select Virtual_PDF_Printer from your applications’ list of available printers and click ‘Print’, a pop-up window should appear, allowing you to select the target directory for the PDF file and enter a file name of your choice.

Fix for ALSA Speaker volume level resetting to zero at boot

Up until 2011 the problem of the volume level in ALSA resetting to zero at boot was a common occurrence in my Linux installations. Actually it was a common occurrence in Linux, full stop; search the Web using keywords such as “alsa reset volume” and you’ll find umpteen links. In 2012 the situation improved and I thought the problem had become a thing of the past, but it resurfaced in 2013 on my main laptop and has plagued me through every update since (well, apart from in one release of KDE). Every time I reboot, the ALSA Speaker channel’s volume is zero when I log-in to KDE. And, as KMix is a PulseAudio mixer by default these days, I have to launch ALSAMixer and raise the volume of the Speaker channel manually.

I don’t know if the source of the problem lies in KDE, PulseAudio or ALSA itself. It did disappear after one upgrade to KDE earlier this year (I don’t recall which release of KDE) but returned in the next KDE upgrade, so I suspect it is a KDE issue. In earlier days I could resolve the problem using the commands alsactrl store and alsactl restore and similar approaches. However, this time none of those fixes work for me. The problem never bothered me much, as I always connect external speakers to my laptop’s headphone socket when I’m at home, and I don’t want my laptop emitting sounds at the office. Nevertheless, the fact the problem exists niggled me, so I decided to try and fix it. Rather than expending any more effort trying to get the usual approaches to work (the Web is littered with suggested fixes over the years), I decided to reset the Speaker volume to the same level at each boot by using an automatically-launched shell script. The method I use is given below, and should work with either OpenRC or systemd in Gentoo Linux.

1. Create the file /etc/local.d/20set_alsa_volume.start containing the following:

#!/bin/bash
# Reset ALSA Speaker channel on the first sound card to 90% after booting.
su -c "amixer -c 0 -- sset Speaker playback 90%" -s /bin/sh fitzcarraldo

(Replace “fitzcarraldo” with your own user name, of course.)

2. Make the script executable:

# chmod +x 20set_alsa_volume.start

That’s all there is to it. The volume of the ALSA Speaker channel is always set to 90% after I reboot and login to the desktop environment. KMix remembers the PulseAudio volume setting from the previous session, so I can still avoid blasting the laptop’s speakers.

By the way, the manual pages for the amixer and alsamixer commands make useful reading:

$ man amixer
$ man alsamixer

For example, the first audio card (Card 0) in my main laptop has the following controls:

$ amixer -c 0 scontrols
Simple mixer control ‘Master’,0
Simple mixer control ‘Headphone’,0
Simple mixer control ‘Speaker’,0
Simple mixer control ‘PCM’,0
Simple mixer control ‘Mic’,0
Simple mixer control ‘Mic Boost’,0
Simple mixer control ‘Beep’,0
Simple mixer control ‘Capture’,0
Simple mixer control ‘Auto-Mute Mode’,0
Simple mixer control ‘Digital’,0
Simple mixer control ‘Internal Mic’,0
Simple mixer control ‘Internal Mic Boost’,0

Update (January 29, 2015): I found the cause of the problem: PulseAudio. I edited the file /usr/share/pulseaudio/alsa-mixer/paths/analog-output.conf as per user agmg‘s January 2013 post Re: [SOLVED] Problems with PulseAudio 3.0 in the PCLinuxOS Forums:

Again, I had to edit the file: /usr/share/pulseaudio/alsa-mixer/paths/analog-output.conf

and change this:

[Element Speaker]
switch = mute
volume = off

to this:

[Element Speaker]
switch = mute
volume = merge

I realized that editing the [Element Desktop Speaker] section of the above file, has no effect on the issue. Only the edit to [Element Speaker] is needed in my case.

In my case this change forces the ALSA Speaker channel volume to 100% after rebooting (irrespective of the volume levels I set via ALSAMixer and KMix before shutdown).

The contents of the file /usr/share/pulseaudio/alsa-mixer/paths/analog-output.conf also include the following comment:

; See analog-output.conf.common for an explanation on the directives

The contents of the file analog-output.conf.common include the following comment:

; volume = ignore | merge | off | zero | <volume step> # What to do with this volume: ignore it, merge it into the device
;                                                      # volume slider, always set it to the lowest value possible, or always
;                                                      # set it to 0 dB (for whatever that means), or always set it to
;                                                      # <volume step> (this only makes sense in path configurations where
;                                                      # the exact hardware and driver are known beforehand).

So I could have tried volume = <volume step> instead of volume = merge, although I have no idea what value <volume step> would need to be. Anyway, the Bash script /etc/local.d/20set_alsa_volume.start that I created does the job in a different way without me having to tinker with the troublesome PulseAudio, so I reverted to volume = off in the file analog-output.conf and reverted to using /etc/local.d/20set_alsa_volume.start as explained earlier.

Laptop Mode Tools revisited due to a change in its functionality

The site statistics for this blog can be quite revealing. For example, over the last two or three months I noticed that my post How to prevent a USB mouse auto-suspending in Linux when a laptop’s power supply is disconnected has consistently been one of the most viewed. Given the problems I experienced with Laptop Mode Tools 1.65 (see my Gentoo Linux Forums post Bug in laptop-mode-tools-1.65? and Gentoo Linux Bugzilla Bug Report No. 520124), I was not entirely surprised. Thanks to fellow Gentoo Linux and Laptop Mode Tools user Ted Tanberry I learned that Version 1.65 had stopped using Laptop Mode Tools module usb-autosuspend, and started using Laptop Mode Tools module runtime-pm instead. At least that was the developer’s intention, but he had not implemented it correctly. The aforementioned Gentoo Linux bug report explains in detail the problem with Version 1.65.

The situation in my Gentoo Linux installation with laptop-mode-tools-1.64 installed, providing the functionality I desired, was as follows:

a. The precise package installed:

# eix -I laptop-mode-tools
[U] app-laptop/laptop-mode-tools
Available versions: 1.64 (~)1.65 (~)1.65-r1 (~)1.66 {+acpi apm bluetooth scsi}
Installed versions: 1.64(10:04:43 21/10/14)(acpi bluetooth -apm -scsi)
Homepage: http://www.samwel.tk/laptop_mode/
Description: Linux kernel laptop_mode user-space utilities

b. The auto-suspend state when the laptop PSU was connected:

# for d in /sys/bus/usb/devices/[0-9]* ; do if [[ -e $d/product ]] ; then echo -e "`basename $d`\t`cat $d/power/control`\t`cat $d/speed`\t`cat $d/product`" ; fi ; done
1-1.2 on 1.5 USB Laser Mouse
2-1.2 on 12 Fingerprint Sensor
2-1.3 on 480 USB 2.0 Camera

c. The contents of the file /lib64/udev/rules.d/99-laptop-mode.rules:

ACTION=="change", SUBSYSTEM=="power_supply", RUN+="lmt-udev auto"
ACTION=="add|remove", SUBSYSTEM=="machinecheck", RUN+="lmt-udev auto"
ACTION=="add|remove", SUBSYSTEM=="usb", RUN+="lmt-udev force modules=usb-autosuspend devices=%k"

d. The contents of file /etc/laptop-mode/conf.d/usb-autosuspend.conf:

#
# Configuration file for Laptop Mode Tools module usb-autosuspend.
#
# For more information, consult the laptop-mode.conf(8) manual page.
#
 
 
###############################################################################
# USB autosuspend settings
# ------------------------
#
# If you enable this setting, laptop mode tools will automatically enable the
# USB autosuspend feature for all devices.
#
# NOTE: Some USB devices claim they support autosuspend, but implement it in a
# broken way. This can mean keyboards losing keypresses, or optical mice turning
# their LED completely off. If you have a device that misbehaves, add its USB ID
# to the blacklist below and complain to your hardware vendor.
################################################################################
 
# Enable debug mode for this module
# Set to 1 if you want to debug this module
DEBUG=0
 
# Enable USB autosuspend feature?
# Set to 0 to disable
CONTROL_USB_AUTOSUSPEND="auto"
 
# Set this to use opt-in/whitelist instead of opt-out/blacklist for deciding
# which USB devices should be autosuspended.
# AUTOSUSPEND_USE_WHITELIST=0 means AUTOSUSPEND_*_BLACKLIST will be used.
# AUTOSUSPEND_USE_WHITELIST=1 means AUTOSUSPEND_*_WHITELIST will be used.
AUTOSUSPEND_USE_WHITELIST=0
 
# The list of USB IDs that should not use autosuspend. Use lsusb to find out the
# IDs of your USB devices.
# Example: AUTOSUSPEND_USBID_BLACKLIST="046d:c025 0123:abcd"
AUTOSUSPEND_USBID_BLACKLIST="046d:c052"
 
# The list of USB driver types that should not use autosuspend.  The driver
# type is given by "DRIVER=..." in a USB device's uevent file.
# Example: AUTOSUSPEND_USBID_BLACKLIST="usbhid usb-storage"
AUTOSUSPEND_USBTYPE_BLACKLIST=""
 
# The list of USB IDs that should use autosuspend. Use lsusb to find out the
# IDs of your USB devices.
# Example: AUTOSUSPEND_USBID_WHITELIST="046d:c025 0123:abcd"
AUTOSUSPEND_USBID_WHITELIST=""
 
# The list of USB driver types that should use autosuspend.  The driver
# type is given by "DRIVER=..." in a USB device's uevent file.
# Example: AUTOSUSPEND_USBTYPE_WHITELIST="usbhid usb-storage"
AUTOSUSPEND_USBTYPE_WHITELIST=""
 
# Trigger auto-suspension of the USB deivce under conditional circumstances
BATT_SUSPEND_USB=1
LM_AC_SUSPEND_USB=0
NOLM_AC_SUSPEND_USB=0
 
# USB Auto-Suspend timeout in seconds
# Number of seconds after which the USB devices should suspend
AUTOSUSPEND_TIMEOUT=2

Having experienced the problems with the buggy Laptop Mode Tools 1.65, I re-installed 1.64 and had been using that successfully until a week ago. Then I noticed that 1.66 had been released, so I installed it:

# emerge laptop-mode-tools
.
.
.
>>> Installing (1 of 1) app-laptop/laptop-mode-tools-1.66::gentoo
* To enable automatic power state event handling,
* e.g. enabling laptop_mode after unplugging the battery,
* both laptop_mode and the acpid daemon must be
* added to default runlevel:
* # rc-update add laptop_mode default
>>> Auto-cleaning packages...

>>> No outdated packages were found on your system.

* GNU info directory index is up-to-date.

I would not have expected that ewarn message about adding laptop_mode to the default runlevel, as the ebuild is only supposed to display the warning if laptop_mode is not assigned to the default runlevel. But, sure enough, something had removed it:

# rc-update show -v | grep laptop
laptop_mode |
# rc-update show -v | grep acpi
acpid |      default

I don’t know what removed laptop_mode from the default runlevel. It was certainly assigned previously, as proved by Laptop Mode Tools 1.64 working as expected when I connected and disconnected the laptop’s PSU from the mains (see my earlier post). Anyway, I re-added it:

# rc-update add laptop_mode default
* service laptop_mode added to runlevel default

If you use systemd instead of OpenRC, instead of adding laptop_mode to the default runlevel you would need to use the following command:

# systemctl enable laptop_mode.service

Notice that the incorrect contents of 99-laptop-mode.rules and /etc/laptop-mode/laptop-mode.conf that were present in Laptop Mode Tools 1.65 have been fixed in 1.66:

# cat /lib64/udev/rules.d/99-laptop-mode.rules
ACTION=="change", SUBSYSTEM=="power_supply", RUN+="lmt-udev auto"
ACTION=="add|remove", SUBSYSTEM=="machinecheck", RUN+="lmt-udev auto force"
ACTION=="add|remove", SUBSYSTEM=="usb", RUN+="lmt-udev force modules=runtime-pm devices=%k"

# cat /etc/laptop-mode/laptop-mode.conf | grep usb-autosuspend
#

The ebuild for Laptop Mode Tools 1.66 did not delete the now-redundant file /etc/laptop-mode/conf.d/usb-autosuspend.conf but it is presumably ignored by 1.66 anyway.

From now on I must configure the contents of /etc/laptop-mode/conf.d/runtime-pm.conf instead. After installing Laptop Mode Tools 1.66 it contained the following:

#
# Configuration file for Laptop Mode Tools module runtime-pm
#
# For more information, consult the laptop-mode.conf(8) manual page.
#


###############################################################################
# Runtime Power Management Settings
# ---------------------------------
#
#__COMMENT If you enable this setting, laptop mode tools will automatically enable
#__COMMENT the Runtime Power Management feature for all devices.
#__COMMENT
#__COMMENT NOTE: Some devices claim they support autosuspend, but implement it in a
#__COMMENT broken way. This can mean keyboards losing keypresses, or optical mice
#__COMMENT turning their LED completely off. If you have a device that misbehaves,
#__COMMENT add its DEVICE ID to the blacklist section below and complain to your
#__COMMENT hardware / device driver contact
#
################################################################################

# Enable debug mode for this module
# Set to 1 if you want to debug this module
DEBUG=0

# Enable Runtime autosuspend feature?
# Set to 0 to disable
CONTROL_RUNTIME_AUTOSUSPEND=1

# Set this to use opt-in/whitelist instead of opt-out/blacklist for deciding
# which devices should be autosuspended.
# AUTOSUSPEND_USE_WHITELIST=0 means AUTOSUSPEND_*_BLACKLIST will be used.
# AUTOSUSPEND_USE_WHITELIST=1 means AUTOSUSPEND_*_WHITELIST will be used.
AUTOSUSPEND_USE_WHITELIST=0

# The list of Device IDs that should not use autosuspend. Use system commands or
# look into sysfs to find out the IDs of your devices.
# Example: AUTOSUSPEND_DEVID_BLACKLIST="046d:c025 0123:abcd"
AUTOSUSPEND_RUNTIME_DEVID_BLACKLIST=""

# The list of device driver types that should not use autosuspend.  The driver
# type is given by "DRIVER=..." in a device's uevent file.
# Example: AUTOSUSPEND_DEVID_BLACKLIST="usbhid usb-storage"
AUTOSUSPEND_RUNTIME_DEVTYPE_BLACKLIST=""

# The list of Device IDs that should use autosuspend. Use system commands or
# look into sysfs to find out the IDs of your devices.
# Example: AUTOSUSPEND_DEVID_WHITELIST="046d:c025 0123:abcd"
AUTOSUSPEND_RUNTIME_DEVID_WHITELIST=""

# The list of device driver types that should use autosuspend.  The driver
# type is given by "DRIVER=..." in a device's uevent file.
# Example: AUTOSUSPEND_DEVTYPE_WHITELIST="usbhid usb-storage"
AUTOSUSPEND_RUNTIME_DEVTYPE_WHITELIST=""

# Trigger auto-suspension of the deivce under conditional circumstances
# Warning: DO NOT CHANGE THESE DEFAUTLS UNLESS YOU KNOW
BATT_SUSPEND_RUNTIME=1
LM_AC_SUSPEND_RUNTIME=1
NOLM_AC_SUSPEND_RUNTIME=1

# Auto-Suspend timeout in seconds
# Number of seconds after which the USB devices should suspend
AUTOSUSPEND_TIMEOUT=2

So, in order to stop my laptop’s USB mouse, USB external keyboard and some internal USB devices from going to sleep when my laptop is only on battery power, I made the following change to a line in /etc/laptop-mode/conf.d/runtime-pm.conf:

# External keyboard at one office, internal Webcam, internal fingerprint sensor, Logitek NX50 notebook mouse
AUTOSUSPEND_RUNTIME_DEVID_BLACKLIST="03f0:0024 064e:a115 147e:1001 046d:c052"

My earlier post about Laptop Mode Tools explained one method for finding the device ID for each USB device, but the lsusb command can also be used:

# lsusb
Bus 002 Device 005: ID 03f0:0024 Hewlett-Packard KU-0316 Keyboard <---- External keyboard at one office
Bus 002 Device 004: ID 064e:a115 Suyin Corp. <---- Built-in Webcam
Bus 002 Device 003: ID 147e:1001 Upek TCS5B Fingerprint sensor <---- Built-in fingerprint sensor
Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 046d:c052 Logitech, Inc. <----Logitech NX50 notebook mouse
Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

Although the Laptop Mode Tools usb-autosuspend module is supposed to be unused in 1.66, I edited /etc/laptop-mode/conf.d/usb-autosuspend.conf (which was not deleted by the 1.66 ebuild) and changed CONTROL_USB_AUTOSUSPEND="auto" to CONTROL_USB_AUTOSUSPEND="0" just to be on the safe side.