[PATCH 0/1][SRU][L][M] Various backlight issues with the 6.0/6.1 kernel

[AceLan Kao]

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

BugLink: https://bugs.launchpad.net/bugs/2023638

[Impact]
There are some new patches for new method to decide which backlight driver
should be registered introduced since 6.1. And we backport some of them to
6.0-oem kernel which are not enough to solved all backlight issues.
1. dell_laptop created a non-working backlight driver before nvidia is
   loaded, that leads to the system can't adjust the display brightness.
2. acpi_backlight0 sometimes will be generated together with intel_backlight.

[Fix]
Below 2 commits from v6.3-rc6 prevent the acpi_backlight from being
registered automatically(which have been included into ubuntu kernels
through stable update)
e506731c8f35 ACPI: video: Make acpi_backlight=video work independent from GPU driver
78dfc9d1d1ab ACPI: video: Add auto_detect arg to __acpi_video_get_backlight_type()

Below patch prevents platform driver(dell_laptop) from creating backlight
driver after win8.
aa8a950a5d6b ACPI: video: Stop trying to use vendor backlight control on laptops from after ~2012
https://patchwork.kernel.org/project/linux-acpi/patch/20230608091258.7963-1-hdegoede@redhat.com/

[Test]
Verified on the dell platform which reports this issue.

[Where problems could occur]
The assumption of the last commit regarding backlight control is that,
after Windows 8, all laptop backlights are controlled either by ACPI or the
native graphics driver. It impacts the laptops that do not follow the
assumption and will lead to no backlight interface is generated. We
don't see this case in our OEM projects for several years.

Hans de Goede (1):
  ACPI: video: Stop trying to use vendor backlight control on laptops
    from after ~2012

 drivers/acpi/video_detect.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

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2.34.1