Stopping my laptop spontaneously resuming immediately after Suspend to RAM

If I selected ‘Suspend to RAM’ via the Desktop Environment in the Gentoo Linux installation on my Clevo W230SS laptop, the laptop did suspend but then immediately resumed automatically. The same thing happened if I suspended the laptop using either of the following commands from the command line:

root # pm-suspend

user $ qdbus org.kde.Solid.PowerManagement /org/freedesktop/PowerManagement Suspend

This behaviour was annoying, as it meant I had to shut down the laptop completely when I was not at my desk for a long time, rather than just being able to suspend the laptop.

Problem 1: USB devices

I usually have several USB devices connected to my laptop when I am at home or in the office, and I began to suspect that these USB connections were somehow causing Linux to resume as soon as it had suspended. Searching the Web turned up a Q&A page that seemed to confirm my suspicion: Why does my laptop resume immediately after suspend? I installed the utility acpitool mentioned on that Web page and used it with the ‘-w‘ option to check which wakeup-capable USB devices were currently enabled in my installation:

root # acpitool -w
   Device       S-state   Status   Sysfs node
  ---------------------------------------
  1. RP01         S4    *disabled  pci:0000:00:1c.0
  2. PXSX         S4    *disabled
  3. RP02         S4    *disabled
  4. PXSX         S4    *disabled
  5. RP03         S4    *disabled  pci:0000:00:1c.2
  6. PXSX         S4    *disabled  pci:0000:03:00.0
  7. RP04         S4    *disabled  pci:0000:00:1c.3
  8. PXSX         S4    *disabled  pci:0000:04:00.0
  9.            *disabled  platform:rtsx_pci_sdmmc.0
  10.           *disabled  platform:rtsx_pci_ms.0
  11. RLAN        S4    *disabled
  12. RP05        S4    *disabled
  13. PXSX        S4    *disabled
  14. RP06        S4    *disabled
  15. PXSX        S4    *disabled
  16. RP07        S4    *disabled
  17. PXSX        S4    *disabled
  18. RP08        S4    *disabled
  19. PXSX        S4    *disabled
  20. GLAN        S4    *disabled
  21. EHC1        S3    *enabled   pci:0000:00:1d.0
  22. EHC2        S3    *enabled   pci:0000:00:1a.0
  23. XHC         S3    *disabled  pci:0000:00:14.0
  24. HDEF        S4    *disabled  pci:0000:00:1b.0
  25. PEG0        S4    *disabled  pci:0000:00:01.0
  26. PEGP        S4    *disabled  pci:0000:01:00.0
  27. PEGA        S4    *disabled
  28. PWRB        S3    *enabled   platform:PNP0C0C:0
^C
root #

(I had to use Ctrl-C to get back to the command prompt.)

I then used the command ‘acpitool -W <device number>‘ on each of the three enabled devices (21, 22 and 28 above) in order to find out which of them needed to be disabled in order for my laptop to remain suspended when I suspended it. I found that I only needed to disable devices EHC1 (pci:0000:00:1d.0) and EHC2 (pci:0000:00:1a.0) to be able to suspend the laptop successfully:

root # acpitool -W 21 | grep 21
  Changed status for wakeup device #21 (EHC1)
  21. EHC1        S3    *disabled  pci:0000:00:1d.0
^C
root # acpitool -W 22 | grep 22
  Changed status for wakeup device #22 (EHC2)
  22. EHC2        S3    *disabled  pci:0000:00:1a.0
^C
root # pm-suspend

In this laptop these two devices are two internal USB root hubs:

user $ lsusb -t
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/8p, 480M
        |__ Port 2: Dev 3, If 0, Class=Hub, Driver=hub/4p, 480M
            |__ Port 1: Dev 4, If 0, Class=Mass Storage, Driver=usb-storage, 480M
            |__ Port 3: Dev 5, If 0, Class=Mass Storage, Driver=usb-storage, 480M
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M
        |__ Port 2: Dev 3, If 0, Class=Hub, Driver=hub/4p, 480M
            |__ Port 1: Dev 6, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M
            |__ Port 4: Dev 7, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M
            |__ Port 4: Dev 7, If 1, Class=Human Interface Device, Driver=usbhid, 1.5M
        |__ Port 3: Dev 4, If 0, Class=Wireless, Driver=btusb, 12M
        |__ Port 3: Dev 4, If 1, Class=Wireless, Driver=btusb, 12M
        |__ Port 4: Dev 5, If 0, Class=Video, Driver=uvcvideo, 480M
        |__ Port 4: Dev 5, If 1, Class=Video, Driver=uvcvideo, 480M

The next challenge was to find out how to disable and re-enable the two devices automatically when I suspend and resume the installation. Further searching of the Web turned up another Q&A page which pointed me in the right direction: How to run a script when suspending/resuming?. It turns out that you need to put a script of the following form in the directory /etc/pm/sleep.d/:

#!/bin/bash

case "$1" in
    suspend)
        # executed on suspend
        ;;
    resume) 
        # executed on resume
        ;;
    *)
        ;;
esac

If you want the script to run when hibernating and thawing, the tests would be for ‘hibernate‘ and ‘thaw‘ instead of ‘suspend‘ and ‘resume‘.

The thread [SOLVED] Computer immediately resumes after suspend in the KDE Forums almost gave me the solution I needed. I created a file /etc/pm/sleep.d/01-toggle-usb-hubs containing the following:

#!/bin/sh
#
username=fitzcarraldo
userhome=/home/$username
export XAUTHORITY="$userhome/.Xauthority"
export DISPLAY=":0"
#
case "$1" in
    suspend|hibernate)
        # Unbind ehci-pci for the device 0000:00:1a.0
        echo -n "0000:00:1a.0" | tee /sys/bus/pci/drivers/ehci-pci/unbind
        # Unbind ehci-pci for the device 0000:00:1d.0
        echo -n "0000:00:1d.0" | tee /sys/bus/pci/drivers/ehci-pci/unbind
    ;;
    resume|thaw)
        # Bind ehci-pci for the device 0000:00:1a.0
        echo -n "0000:00:1a.0" | tee /sys/bus/pci/drivers/ehci-pci/bind
        # Bind ehci-pci for the device 0000:00:1d.0
        echo -n "0000:00:1d.0" | tee /sys/bus/pci/drivers/ehci-pci/bind
    ;;
    *)
        exit $NA
    ;;
esac

I obtained the device details from the output of the ‘acpitools -w‘ command listed earlier and by looking in the directory /sys/bus/pci/drivers/ehci-pci:

root # ls /sys/bus/pci/drivers/ehci-pci
0000:00:1a.0  0000:00:1d.0  bind  new_id  remove_id  uevent  unbind

Notice that the script tests for either ‘suspend‘ or ‘hibernate‘ to disable the two devices, and tests for either ‘resume‘ or ‘thaw‘ to enable the two devices.

I made the script executable:

root # chmod +x /etc/pm/sleep.d/01-toggle-usb-hubs

Problem 2: Blank X Windows display due to NVIDIA closed-source driver bug

However, a problem remained: My laptop has an NVIDIA GPU and, when resuming from suspension, the X Windows display (Virtual Terminal 7) was a blank screen with only the mouse pointer visible. Now, it so happens that I also experience this behaviour if I switch from Virtual Terminal 7 to e.g. Virtual Terminal 1 (Ctrl-Alt-F1) and then switch back to Virtual Terminal 7 (Ctrl-Alt-F7). Apparently this is due to a bug in the closed-source NVIDIA driver (I am currently using Gentoo package x11-drivers/nvidia-drivers-358.16-r1). However, if I first disable compositing before switching to another virtual terminal, the X Windows display on Virtual Terminal 7 is still visible when I switch back to Virtual Terminal 7. It turns out there is a known bug in the NVIDIA closed-source driver, as explained in the following KDE bug report and thread in the NVIDIA CUDA ZONE Forums:

KDE Bugtracking System Bug No. 344326 – Black or corrupted screen on resume from suspend

NVIDIA CUDA ZONE Forums – Black screen on resume from suspend with 325.15 and KWin 4.11 with enabled compositing

As the suggested work-around is to disable compositing before suspending to RAM, I created a script /etc/pm/sleep.d/02-toggle-compositing containing the following:

#!/bin/sh
#
username=fitzcarraldo
userhome=/home/$username
export XAUTHORITY="$userhome/.Xauthority"
export DISPLAY=":0"
#
case "$1" in
    suspend|hibernate)
        su $username -c "qdbus org.kde.kwin /KWin toggleCompositing" &
    ;;
    resume|thaw)
        su $username -c "qdbus org.kde.kwin /KWin toggleCompositing" &
    ;;
    *)
        exit $NA
    ;;
esac

As I have KDE 4 on this laptop, I made the script use the command ‘qdbus org.kde.kwin /KWin toggleCompositing‘ to disable/enable compositing, so replace that command with the appropriate command if you are not using KDE 4.

I made the script executable:

root # chmod +x /etc/pm/sleep.d/02-toggle-compositing

Now both the scripts in the directory /etc/pm/sleep.d/ run when I suspend or resume the laptop, and everything works as expected. Mission accomplished! 🙂