ACPI: video: Add backlight=native DMI quirk for HP EliteBook 8460p
authorHans de Goede <hdegoede@redhat.com>
Thu, 19 Jan 2023 16:37:44 +0000 (17:37 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 1 Feb 2023 07:34:44 +0000 (08:34 +0100)
commitaa9483b9454730908892c3e8b0b06810209667c0
treecfe423dd2484eb6dbb40788f64e964234dc2a6a3
parented796e0916a8498b8511d80ddfe0355a58fe5730
ACPI: video: Add backlight=native DMI quirk for HP EliteBook 8460p

[ Upstream commit 9dcb34234b8235144c96103266317da33321077e ]

The HP EliteBook 8460p predates Windows 8, so it defaults to using
acpi_video# for backlight control.

Starting with the 6.1.y kernels the native radeon_bl0 backlight is hidden
in this case instead of relying on userspace preferring acpi_video# over
native backlight devices.

It turns out that for the acpi_video# interface to work on
the HP EliteBook 8460p, the brightness needs to be set at least once
through the native interface, which now no longer is done breaking
backlight control.

The native interface however always works without problems, so add
a quirk to use native backlight on the EliteBook 8460p to fix this.

Fixes: fb1836c91317 ("ACPI: video: Prefer native over vendor")
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2161428
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/acpi/video_detect.c