sleeping laptop and moving between external monitors triggers screen flickering

[Jason Haar]

Note: this has been happening for many of the past kernel releases. Wasn't seeing this under Ubuntu-22.04 until around 6 months ago - but it's been triggering ever since (although not all the time)

Basically I'll be docked at work on my Dell Latitude laptop, pull out the USB-C connector (which power/ethernet/HDMI runs through) and go home. Then plug into a similar dock at home. End result is the same whether it's work->home or home->work, the laptop un-sleeps, monitor comes back to life - but the screen is flickering, wayland seems to think the monitor is waay bigger than it is (eg fonts are big) and it's unusable.

Once in this state, plugging/unplugging cables doesn't help - only a reboot fixes the problem. Then it all works again for several home<->work journey's - until it happens again. No real rhythm to it from what I can see - maybe once every couple of weeks? But definitely related to coming back from sleep-mode

Googling around shows the same symptoms related to the kernel error

i915 0000:00:02.0: [drm] *ERROR* CPU pipe A FIFO underrun: transcoder

Suggested fixes seems to mention it's related to cstate and a suggested fix is to edit /etc/default/grub with

GRUB_CMDLINE_LINUX="i915.enable_psr=0 intel_idle.max_cstate=4"

I'm going to give that a go to see if it helps

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: linux-image-6.2.0-39-generic 6.2.0-39.40~22.04.1
ProcVersionSignature: Ubuntu 6.2.0-39.40~22.04.1-generic 6.2.16
Uname: Linux 6.2.0-39-generic x86_64
ApportVersion: 2.20.11-0ubuntu82.5
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Wed Jan 17 04:03:13 2024
InstallationDate: Installed on 2022-03-13 (673 days ago)
InstallationMedia: Ubuntu 22.04 LTS "Jammy Jellyfish" - Alpha amd64 (20220313)
RebootRequiredPkgs: Error: path contained symlinks.
SourcePackage: linux-signed-hwe-6.2
UpgradeStatus: No upgrade log present (probably fresh install)