[Bug 2144637] Re: [SRU] Fix for i915 PSR issue on SDC panels on Intel PTL

** Summary changed:

- drm/i915/psr: Display freezes after suspend/resume with Panel Replay on SDC eDP panels
+ [SRU] Fix for i915 PSR issue on SDC panels on Intel PTL

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https://bugs.launchpad.net/bugs/2144637

Title:
[SRU] Fix for i915 PSR issue on SDC panels on Intel PTL

Status in HWE Next:
In Progress
Status in linux package in Ubuntu:
In Progress
Status in linux-oem-6.17 package in Ubuntu:
Invalid
Status in linux source package in Noble:
Won't Fix
Status in linux-oem-6.17 source package in Noble:
In Progress
Status in linux source package in Questing:
In Progress
Status in linux-oem-6.17 source package in Questing:
Invalid
Status in linux source package in Resolute:
In Progress
Status in linux-oem-6.17 source package in Resolute:
Invalid

Bug description:
[Impact]
After suspend/resume, the internal display freezes and stops refreshing on
systems with SDC eDP panels using Panel Replay. The display content appears
frozen — typing or mouse movement shows no visual feedback. External
monitors continue to work normally.

The root cause is incorrect handling of Panel Replay Selective Update X
granularity DPCD registers (0xb2 and 0xb3). Per the DP specification,
0xffff means full-line granularity, but the driver did not handle this
special value, causing selective update to fail after suspend/resume.

Upstream bug:
https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/7284

[Fix]
Cherry-pick 5 upstream commits (v6.18 through v7.0-rc3):

- f861e54fb33b5 ("drm/i915/psr: Add panel granularity information into intel_connector")
- 90d8aad11f613 ("drm/i915/psr: Panel Replay SU cap dpcd read return value")
- 1cc854647450 ("drm/i915/psr: Use SU granularity information available in intel_connector")
- ace7dcc818137 ("drm/dp: Add definition for Panel Replay full-line granularity")
- a99cac460ddeb ("drm/i915/psr: Fix for Panel Replay X granularity DPCD register handling")

[Test Plan]
On a system with an SDC eDP panel supporting Panel Replay:

$ for i in $(seq 1 10); do sudo rtcwake -m mem -s 20; sleep 5; done

Without the patch: Internal display freezes after resume.
With the patch: Display refreshes normally after every resume.

[Where problems could occur]
Incorrect granularity handling could cause visual artifacts on panels with
non-0xffff granularity values. All patches are upstream and reviewed by
Intel display maintainers.

[Other Info]
SRU for OEM-6.17, questing, and resolute.

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