[Bug 2046315] Re: panel flickering after the i915.psr2 is enabled

** Changed in: linux (Ubuntu Noble)
Status: Triaged => Fix Committed

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https://bugs.launchpad.net/bugs/2046315

Title:
panel flickering after the i915.psr2 is enabled

Status in HWE Next:
New
Status in linux package in Ubuntu:
Triaged
Status in linux-oem-6.5 package in Ubuntu:
Invalid
Status in linux-oem-6.8 package in Ubuntu:
Fix Released
Status in linux source package in Jammy:
Invalid
Status in linux-oem-6.5 source package in Jammy:
Fix Released
Status in linux-oem-6.8 source package in Jammy:
Invalid
Status in linux source package in Noble:
Fix Committed
Status in linux-oem-6.5 source package in Noble:
Invalid
Status in linux-oem-6.8 source package in Noble:
Fix Released

Bug description:
SRU verificaton for Noble and oem-6.8-noble:

[Impact]
In Dell oem project, we found the graphic is flickering on some
machines, finally we narrowed down the issue on (some specific panels +
i915.psr2 enabled), and the issue was reported to Intel, Intel fixed
the issue in the most recent mainline kernel. Here backporting the
patches to Noble kernel.

It is hard to backport the patches to mantic and oem-6.5, so we wrote
a workaround patch to disable the psr2 for those pannels in the oem-6.5.

https://gitlab.freedesktop.org/drm/intel/-/issues/9739

[Fix]
cherry-pick 8 patches from mainline kernel

[Test]
I applied the patches to Noble kernel and built a testing kernel, and
Dell validated the testing kernel on those machines, the graphic
didn't flicker anymore.

I installed the testing kernel on some machines with Intel 13th, 12th
11th and 10th gen cpu, the grahic worked well too.

[Where problems could occur]
This patchset changes the fast wake settings for some gpu, it is
possible to make the graphic flicker, but this possibility is very
low, since the patchset comes from mainline kernel and we validated
the patchset on different gens of Intel cpus.

===========================================================================

BugLink: https://bugs.launchpad.net/bugs/2046315

[Impact]
On serveral Dell laptops, the screen often displays garbage or the screen is flicking

This PR is just a workaround, the upstream bug is here:
https://gitlab.freedesktop.org/drm/intel/-/issues/9739#note_2187863

After the upstream fix this bug with a real fix, I will revert the
workaround and backport the real fix to Noble and Jammy oem-kernel.

[Fix]
There is no real fix so far, ODM recommends to use a workaround to disable PSR2, this is a temp solution, after we get the real fix, we could revert the temp workaround.

[Test case]

booting with the patched kernel, If the pannel's edid is in the qurik
list, the PSR2 will be disabled (checking
/sys/kernel/debug/dri/0/i915_edp_psr_status; if the pannel's edid is
not in the quirk list, the graphic driver will work as before.

[Where problems could occur]
It is possible that the temp solution couldn't work, then the screen will still show garbage and the screen is flicking, another possible regression is the screen has no problem before, but after running patched kernel, the PSR2 is disabled and the system cost more power, but this possibility is very low, I tested the patched on some dell machines, all worked well.

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