[PATCH 0/2][SRU][F/OEM-5.6/G/U] Enable PSR on HP ZBook Studio G7

[You-Sheng Yang]

BugLink: https://bugs.launchpad.net/bugs/1897501

[Impact]

On some OEM platforms equipped PSR eanbled panels, i915 renders screen
half occupied and corrupted, and restore PSR previously disabled in
LP: #1849947 fixes this issue.

[Fix]

While PSR has been disabled currently in Ubuntu kernels from oem-osp1
5.0 to current unstable 5.9, there is no guaranteed PSR support in
Focal, and PSR is actually planned for v5.10 or later kernels, reverting
the disabling commit ("UBUNTU: SAUCE: drm/i915: Disable PSR by default
on all platforms") doesn't seem a viable solution here.

This patchset introduces a new, Ubuntu only, EDID quirk
'DP_QUIRK_FORCE_PSR_ENABLE' to identify the target panel and overrides
`enable_psr` to -1(chip defaults) when it's set to 0(disabled).

[Test Case]

On the target device, the PSR value should be 0 by default:

  $ sudo cat /sys/module/i915/parameters/enable_psr
  0

When applied, the PSR should be -1 even if no "i915.enable_psr=-1" is
passed as kernel boot parameter, and .

  $ sudo cat /sys/module/i915/parameters/enable_psr
  -1

With drm.debug=0x04, one should also find following message in dmesg:

  [drm:intel_psr_enable_locked [i915]] Enabling PSR2

[Regression Potential]
Low. This affects only the target panel with EDID mfg CMN prod-ID 19-15.

You-Sheng Yang (2):
  UBUNTU: SAUCE: drm/i915/psr: allow overriding PSR disable param by
    quirk
  UBUNTU: SAUCE: drm/dp: add DP_QUIRK_FORCE_PSR_ENABLE quirk to CMN
    prod-ID 19-15

 drivers/gpu/drm/drm_dp_helper.c          | 5 +++++
 drivers/gpu/drm/i915/display/intel_psr.c | 8 ++++++++
 include/drm/drm_dp_helper.h              | 8 ++++++++
 3 files changed, 21 insertions(+)

-- 
2.27.0