[PATCH 0/1][SRU][F][G][H][OEM-5.10] XPS 9510 (TGL) Screen

AceLan Kao acelan.kao at canonical.com
Fri Jun 25 02:13:25 UTC 2021

From: "Chia-Lin Kao (AceLan)" <acelan.kao at canonical.com>

BugLink: https://bugs.launchpad.net/bugs/1933566

Dell XPS 15 9510(TGL) uses DPCD to control backlight, and need to add this
panel to edid_quirk.

kernel: [ 1.719773] i915 0000:00:02.0: [drm] Panel advertises DPCD
backlight support, but VBT disagrees. If your backlight controls don't work
try booting with i915.enable_dpcd_backlight=1. If your machine needs this,
please file a _new_ bug report on drm/i915, see
https://gitlab.freedesktop.org/drm/intel/-/wikis/How-to-file-i915-bugs for

Kernel 5.12+ support the backlight via:
commit: <4a8d79901d5b> ("drm/i915/dp: Enable Intel's HDR backlight
interface (only SDR for now)"), and doesn't need this quirk.

Adding the panel's MFG to edid_quirk makes system switch to use DPCD to
control backlight.

Verified on Dell XPS 9510(TGL)

[Where problems could occur]
The quirk is for a dedicate panel, and won't affect other platforms.

Chia-Lin Kao (AceLan) (1):
  UBUNTU: SAUCE: drm/i915: Force DPCD backlight mode for Dell XPS

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


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