[Bug 1933566] Re: XPS 9510 (TGL) Screen Brightness could not be changed

** Description changed:

[Impact]
+ 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 details.
+
+ Kernel 5.13 or newer use new way to handle DPCD backlight, and do not
+ need to this to the quirk.

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

[Test]
+ Verified on Dell XPS 9510(TGL)

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

** Description changed:

[Impact]
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 details.

- Kernel 5.13 or newer use new way to handle DPCD backlight, and do not
- need to this to the quirk.
+ 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.

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

[Test]
Verified on Dell XPS 9510(TGL)

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

** Tags added: oem-priority originate-from-1933030 somerville

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

Title:
XPS 9510 (TGL) Screen Brightness could not be changed

Status in HWE Next:
New
Status in linux package in Ubuntu:
Invalid
Status in linux-oem-5.10 package in Ubuntu:
Invalid
Status in linux source package in Focal:
In Progress
Status in linux-oem-5.10 source package in Focal:
In Progress
Status in linux source package in Groovy:
In Progress
Status in linux source package in Hirsute:
In Progress

Bug description:
[Impact]
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 details.

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.

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

[Test]
Verified on Dell XPS 9510(TGL)

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

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