ACPI: video: force native backlight on Acer Nitro AN515-46

The Acer Nitro AN515-46 is a hybrid graphics laptop whose internal
panel is driven by the AMD GPU (Radeon 680M); the discrete NVIDIA GPU
only drives external outputs. The firmware nevertheless advertises the
NVIDIA WMI EC backlight GUID, so the backlight type resolves to
nvidia_wmi_ec. The nvidia-wmi-ec-backlight driver however fails to
probe ("EC backlight control failed: AE_NOT_FOUND") and, since the
backlight type is still nvidia_wmi_ec, amdgpu skips registering its
own backlight device. The result is no backlight device at all,
leaving the brightness keys and the desktop brightness slider
non-functional.

Booting with acpi_backlight=native makes amdgpu register its backlight
interface and brightness control works. Add a DMI quirk to use the
native backlight on this model by default.

Signed-off-by: Marcos Paulo Medeiros <maarcospm1996@gmail.com>
Link: https://patch.msgid.link/20260727132151.12792-1-maarcospm1996@gmail.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Marcos Paulo Medeiros 2026-07-27 10:21:51 -03:00 • committed by Rafael J. Wysocki
commit 525ba51157