[SRU][OEM-5.14/Jammy/OEM-5.17][PATCH 0/1] Fix blank screen on Thinkpad ADL 4K+ panel

[Stefan Bader]

On 04.07.22 07:15, Aaron Ma wrote:
> BugLink: https://bugs.launchpad.net/bugs/1980621
> 
> [Impact]
> Set screen off on ThinkPad P1G5 with 4k+ panel.
> The screen will never be back.
> 
> [Fix]
> It's a upstream kernel regression.
> And reverted by upstream.
> 
> [Test]
> Verified on hardware, screen on/off 20 times OK.
> 
> [Where problems could occur]
> Low risk, it reverts a regression and may break i915 driver.
> 
> On 5.14-oem and Jammy kernel, This commit was claimed to backport
> commit 73867c8709b5 ("drm/i915/display: Remove check for low voltage sku for max dp source rate")
> But it's not kind of it.
> So revert it instead.
> 
> On 5.17 kernel, revert it by upstream commit.
> 
> Unstable kernel already got it.
> 
> Jason A. Donenfeld (1):
>    drm/i915/display: Re-add check for low voltage sku for max dp source
>      rate
> 
> Aaron Ma (1):
>    UBUNTU: SAUCE: Revert "drm/i915/display: Remove check for low voltage
>      sku for max dp source rate"
> 
>   drivers/gpu/drm/i915/display/intel_dp.c | 32 ++++++++++++++++++++++---
>   1 file changed, 29 insertions(+), 3 deletions(-)
> 

This would be a case where it would be good also say what was the original 
problem that the patch to be reverted tried to solve. But also the fact that the 
patch in Jammy claims to be a cherry pick but is completely different from the 
upstream patch, yet the SHA1 _are_ identical.

So how can we trust any HWE submission that says cherry pick in the future?
What does the revert in Jammy _actually_ do? Both patches are completely 
different, so is Jammy really affected by the issues which the upstream patch 
caused?

The Jammy patch probably should be reverted under that commit message. The 
question is, should the code get re-applied again with the _CORRECT_ provenance?

-Stefan
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