Weird behavior on display, since kernel versions 5.15.x

[neblaz]

Since kernel versions 5.15.x I have a problem with graphics unit and display on screen.

I described it first time here

https://discourse.lubuntu.me/t/lubuntu-jammy-weird-artifacts-on-display-choose-older-kernel-version-to-boot-with/3034

and recently here

https://discourse.lubuntu.me/t/weird-behavior-on-display-since-kernel-versions-5-15-x/3446

Don't know what information else to provide, please advice.

[lotuspsychje (lotuspsychje)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command only once, as it will automatically gather debugging information, in a terminal:
apport-collect 1981901

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

[neblaz (neblaz)]

When I run apport-collect 1981901 I see some Login information in terminal, but cannot proceed.
At the very bottom it shows arrow up and arrow down Viewing [SSL] <Log in>

Did you receive some debugging information meanwhile?

[lotuspsychje (lotuspsychje)]

Could it be due using another browser then the default one
giving you that apport error? wich browser are you using?

[Daniel van Vugt (vanvugt)]

If the above command does not work then please run:

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

and attach the resulting text files along with a photo of the issue here.

[neblaz (neblaz)]

@vanvugt
Interestingly I could only choose 1 file to attach, here is the other one.

[neblaz (neblaz)]

@vanvugt
Here the other one. I cannot make a photo, it happens unpredictable and only for a fraction of a second. I described it as good as possible in the provide Lubuntu forum links.

[Daniel van Vugt (vanvugt)]

Thanks. Unfortunately there is less info in that Lubuntu log than I would usually expect from regular Ubuntu. So I will guess...

Three known issues come to mind:

 * Intel flickering regression in kernel 5.15: bug 1958191. For most people the fix is either kernel parameter intel_iommu=igfx_off or just kernel update >= 5.15.0-40 (in Ubuntu 22.04 only right now).

 * If you are using Xorg then make sure you're not using the old Intel graphics driver: bug 1867668.

 * Some laptops have LCD panels that require a kernel parameter to stop flickering: i915.enable_psr=0

[neblaz (neblaz)]

@vanvugt
Thanks, will see...

* I have to wait until >= 5.15.0-40 is available or set the kernel parameter, but how/where to set it?

* I'm not sure if I use Xorg, but assume that is the default in Lubuntu. Where/how to check if Xorg ist used? And usually I would use the new stuff, so what is the old Intel graphics driver and what is the new one? How to switch between old and new? I read in regards to xserver-xorg-video-intel:
This package is built from the X.org xf86-video-intel driver module. The use of this driver is discouraged if your GPU is new enough (ca. 2007 and newer).

Mine is an Intel Celereon J4105 with Intel UHD 600 (which is from 2017), so I can remove in fact xserver-xorg-video-intel. After removal my Lubuntu Kinetic uses the Intel graphics drivers which are in the kernel?

The only thing I see in Lubuntu > Preferences > LXQt Settings > Window Effects are the 2 options: X Render and GLX (OpenGL)... I selected GLX (OpenGL). But I think, that is not what you mean, this is only related to window effects when Compton is used, I understand.

* I dont't have a laptop, I have a mini-pc and use an external monitor via HDMI. Anyway, where to set that parameter, just to try out?

[neblaz (neblaz)]

@vanvugt
I tried to set intel_iommu=igfx_off on boot, so to test temporarily with that parameter, and it looks like it solved the problem, excellent!

So best to wait until >= 5.15.0-40 comes out, when will that happen (for Lubuntu)?

[Chris Guiver (guiverc)]

Yes Lubuntu with LXQT uses Xorg

FYI: the X in LXQt; Lubuntu doesn't support LWQt which currently is only for testing.

[Daniel van Vugt (vanvugt)]

To set a kernel parameter permanently, add it to /etc/default/grub in GRUB_CMDLINE_LINUX_DEFAULT. Then run:

  sudo update-grub

and reboot.

[neblaz (neblaz)]

Thanks!
Why can't I see the bug report in my Bugs category anymore? It was there listed but today gone.

[Daniel van Vugt (vanvugt)]

The bug gets hidden from normal searches now that it is marked as a duplicate.

Try an advanced search: https://bugs.launchpad.net/~/+bugs?advanced=1