[Notebook N7x0WU] Random black flickers in gnome-shell Wayland sessions

Thanks for the bug report. Are the flashes light or dark?

Next time it happens, please immediately run:

  journalctl -b0 > journal.txt
  lspci -kv > lspci.txt

and attach the resulting text files here.

@ Daniel

its a bit hard to say wich colour, as the flashes go so fast, like a fast screenshot
when leaving a journalctl -f open i cant see any errors on the time of the flashes

Thanks. Please try these fixes separately so we can see which one if any avoids the problem:

------------------------------------------------

1. Edit /etc/default/grub and change:

   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

   to

   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash i915.enable_psr=0"

2. Run: sudo update-grub

3. Reboot.

------------------------------------------------

1. Edit /etc/environment and add a line:

   MUTTER_DEBUG_ENABLE_ATOMIC_KMS=0

2. Reboot.

------------------------------------------------

@Daniel i tested both fixes for several hours individualy
but the flashes seem to keep happening

is there some sort of wayland realtime debug command i could try
to see if i can trace on the time its happening, as in journal logs nothing shows?

Wayland is only a communication protocol between the app and the server. The underlying screen updates are implemented by gnome-shell (via libmutter) using KMS. You can make it log LOTS of information by adding this to /etc/environment:

  MUTTER_DEBUG=kms

If you do that and then record a separate log each time a flash happens:

  journalctl -b0 > anotherflash.txt

then that might be useful.

i had a screen flash around 10h58

logs in attachment

The only error I can see around 10:58 is bug 1948589 so maybe we should eliminate that first.

Please enable both the suggestions in comment #5, and then follow comment #7 again.

i had a screen flash on 11h39

with:

quiet splash i915.enable_psr=0
MUTTER_DEBUG_ENABLE_ATOMIC_KMS=0
MUTTER_DEBUG=kms

enabled

i tryed journalctl -f in realtime too with the kms logs running

and when a flash occurs i cant seem to pinpoint errors on the seconds it happens

Again I can't see any KMS errors but it is suspicious that bug 1948589 occurred around the time you mention. I'm starting to think this isn't a KMS issue at all.

Can you please take a video of the issue using a camera or phone?

Do you have your background wallpaper set to change automatically? If so then you might see this flash periodically: https://gitlab.gnome.org/GNOME/mutter/-/issues/1882

The screen record of the glitch

@Daniel #14

i have 1 wallpaper active, not automaticly changed

I also tested quiet splash mitigations=off without luck

Thanks for the video! That "flash" seems to be the whole screen flickering to black. It can happen if the Wayland backend fails to assign a buffer to the screen for a frame. But it can also happen with monitor connection issues that may be hardware or software (kernel) problems. That's less likely on a laptop but not impossible (I've seen it there too).

Let's assume it's a software bug in Mutter's Wayland backend, but I am out of ideas right now other than using 'Ubuntu on Xorg' as a workaround.

Status changed to 'Confirmed' because the bug affects multiple users.

I've merged your old bug 1838644 into this one.

I tried booting with quiet splash intel_idle.max_cstate=4 like my old flickering bug, but no luck the flashes seem to persist

Not sure if this would be relevant to this bug
but i can seem to reproduce a glitch inside gnomes systemsettings
toggle enable/disable the dock autohiding makes it glitch inside the systemsettings window

https://gitlab.freedesktop.org/drm/intel/-/issues/5569
Could this also be related?
I got this on Xorg as well, so it could be different...

@ Jimmy #23

thank you for your suggest, your bug looks very interesting
my flickering however is really bad, results in a full screen unworkable state
but it looks a lot like yours too

i had this bug on ubuntu 18.04 & 22.04, on 20.04 with kernel 5.4 series it did not occur for me