[PATCH v2 0/1] [SRU][H] UBUNTU: SAUCE: Fix backlight control on Samsung 16727 panel

[Aaron Ma]

BugLink: https://bugs.launchpad.net/bugs/1930527

[Impact]
Backlight can't be controlled on 5.11- version of kernel.

[Fix]
The panel needs DPCD to get control of backlight on 5.11- kernel.
After 5.12 kernel introduced new Intel HDR backlight control, and it
works well on this panel.
Add quirk ID to enable DPCD on 5.11- kernel.

Because upstream kernel already got a fix, this patch is not going
to linus's tree. it's only for 5.11- stable kernel.
This patch had been submitted to stable kernel twice, and got Acked
by maintainer too. But still not applied.

Regression:
It adds ID to use DPCD AUX control, it should be safe as UBUNTU SAUCE patch
for other panels.

[Test]
Vendor Verified on hardware, with this quirk backlight can be changed on
5.11 kernel.

[Where problems could occur]
The panel backlight may not be changed.

Aaron Ma (1):
  UBUNTU: SAUCE: drm/i915: Force DPCD backlight mode for Samsung 16727
    panel

 drivers/gpu/drm/drm_dp_helper.c | 1 +
 1 file changed, 1 insertion(+)

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2.25.1