[0/2] ACPI: video: More backlight quirks

Hi Rafael,

With the backlight changes landing in 6.1.y now showing up in
distribution repositories I have been receiving a steady stream of
backlight bug reports by email.

These bug-reports fall into various categories and most of them are
already fixed with some recent fixes which are in 6.1.7 and later.

One category (unfortunately) requires adding DMI quirks.

I have been receiving reports from users with pre Windows 8 laptops,
who used to pass acpi_backlight=vendor on the kernel commandline to hide
a non functioning acpi_video# backlight device, so that userspace will
use the native (GPU driver) backlight device instead.

Starting with 6.1.y acpi_backlight=vendor is now also honored by
the native backlight drivers, hiding the native backlight device,
leaving these users with no backlight device at all.

This leads to them sending me a bug-report. Which in a way is a good
thing because these models really needed to have a DMI quirk added
all along, but this was never reported upstream.

The fix here is to use "acpi_backlight=native" and to set this through
a DMI quirk so that things will work out of the box.

The Acer Aspire 4810T quirk from a couple of days was like this and
the first quirk in this series is too.

I expect to receive more bug-reports like this, so you can expect
a steady trickle of backlight quirk patches from me the coming time.

Note the second quirk in this series is also a "acpi_backlight=native"
quirk, but the root cause is somewhat different, see the commit msg.

Regards,

Hans



Hans de Goede (2):
  ACPI: video: Add backlight=native DMI quirk for HP Pavilion g6-1d80nr
  ACPI: video: Add backlight=native DMI quirk for HP EliteBook 8460p

 drivers/acpi/video_detect.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

On Thu, Jan 19, 2023 at 5:38 PM Hans de Goede <hdegoede@redhat.com> wrote:
>
> Hi Rafael,
>
> With the backlight changes landing in 6.1.y now showing up in
> distribution repositories I have been receiving a steady stream of
> backlight bug reports by email.
>
> These bug-reports fall into various categories and most of them are
> already fixed with some recent fixes which are in 6.1.7 and later.
>
> One category (unfortunately) requires adding DMI quirks.
>
> I have been receiving reports from users with pre Windows 8 laptops,
> who used to pass acpi_backlight=vendor on the kernel commandline to hide
> a non functioning acpi_video# backlight device, so that userspace will
> use the native (GPU driver) backlight device instead.
>
> Starting with 6.1.y acpi_backlight=vendor is now also honored by
> the native backlight drivers, hiding the native backlight device,
> leaving these users with no backlight device at all.
>
> This leads to them sending me a bug-report. Which in a way is a good
> thing because these models really needed to have a DMI quirk added
> all along, but this was never reported upstream.
>
> The fix here is to use "acpi_backlight=native" and to set this through
> a DMI quirk so that things will work out of the box.
>
> The Acer Aspire 4810T quirk from a couple of days was like this and
> the first quirk in this series is too.
>
> I expect to receive more bug-reports like this, so you can expect
> a steady trickle of backlight quirk patches from me the coming time.
>
> Note the second quirk in this series is also a "acpi_backlight=native"
> quirk, but the root cause is somewhat different, see the commit msg.
>
> Regards,
>
> Hans
>
>
>
> Hans de Goede (2):
>   ACPI: video: Add backlight=native DMI quirk for HP Pavilion g6-1d80nr
>   ACPI: video: Add backlight=native DMI quirk for HP EliteBook 8460p
>
>  drivers/acpi/video_detect.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
>
> --

Both applied as 6.2-rc material, thanks!