Lubuntu 18.04 ‘Gave up waiting for suspend/resume device’

Software Updater in Lubuntu 17.10 recently prompted me to upgrade the OS to 18.04 LTS, and I clicked on ‘Yes, Upgrade Now’. The upgrade was performed and I was able to boot the PC into 18.04, login and access the Desktop as usual. However, I noticed a new message ‘Gave up waiting for suspend/resume device‘ was displayed on TTY1.

Now, I recalled that the Lubuntu 17.10 Installer had created a swap file rather than a swap partition when I installed Lubuntu, as confirmed in the output listed below:

user $ sudo blkid
[sudo] password for fitzcarraldo: 
/dev/sda1: UUID="3602-BD57" TYPE="vfat" PARTLABEL="EFI System Partition" PARTUUID="72b3693e-b81f-7299-84fb-bf3781bef43d"
/dev/sda2: UUID="afe17116-26fa-4169-b2d9-fb6ac8afc63c" TYPE="ext4" PARTUUID="738fed17-293d-832f-c7a4-e83471fe8ca6"

user $ swapon
NAME      TYPE SIZE USED PRIO
/swapfile file   2G   0B   -2
user $ ls /swapfile 
/swapfile

The initramfs installed by upgrading to Lubuntu 18.04 expects a swap partition in order to resume from hibernation:

user $ lsinitramfs /initrd.img | grep resume
scripts/local-premount/resume
bin/resume
conf/conf.d/resume

And, when I regenerated the initramfs files for the three kernel images in the /boot directory, I could see from the terminal output that the update-initramfs tool was expecting a swap partition:

user $ sudo update-initramfs -u -k all
update-initramfs: Generating /boot/initrd.img-4.15.0-23-generic
W: initramfs-tools configuration sets RESUME=UUID=7b4cb3c5-4c17-42ae-be3c-cc35d31fe287
W: but no matching swap device is available.
update-initramfs: Generating /boot/initrd.img-4.15.0-22-generic
W: initramfs-tools configuration sets RESUME=UUID=7b4cb3c5-4c17-42ae-be3c-cc35d31fe287
W: but no matching swap device is available.
update-initramfs: Generating /boot/initrd.img-4.13.0-43-generic
W: initramfs-tools configuration sets RESUME=UUID=7b4cb3c5-4c17-42ae-be3c-cc35d31fe287
W: but no matching swap device is available.

I had a look in the file /etc/initramfs-tools/conf.d/resume and found that it had indeed been configured to expect a swap partition, although I have no idea where that UUID came from, as it was not for any of the partitions on this PC:

user $ cat /etc/initramfs-tools/conf.d/resume
RESUME=UUID=7b4cb3c5-4c17-42ae-be3c-cc35d31fe287

So I edited the contents of the configuration file to point to the swap file /swapfile instead of a non-existent partition:

user $ cat /etc/initramfs-tools/conf.d/resume
#RESUME=UUID=7b4cb3c5-4c17-42ae-be3c-cc35d31fe287
RESUME=/swapfile

Then I regenerated the initramfs files for the three kernel images currently in /boot on the PC:

user $ sudo update-initramfs -u -k all
update-initramfs: Generating /boot/initrd.img-4.15.0-23-generic
update-initramfs: Generating /boot/initrd.img-4.15.0-22-generic
update-initramfs: Generating /boot/initrd.img-4.13.0-43-generic

As you can see above, there were no longer any messages that ‘no matching swap device is available‘. And, when I rebooted the PC, the message ‘Gave up waiting for suspend/resume device‘ was no longer displayed on TTY1. All good again, although it’s a pity the Lubuntu Installer did not create a swap partition so that the installation could be put into hibernation. With a swap file, hibernation is not possible.

Update (14 July 2018): Actually, it is possible to hibernate if the installation has a swap file instead of a swap partition – see my latest post: Configuring Lubuntu 18.04 to enable hibernation using a swap file.