Files
linux/drivers/acpi/video_detect.c
Hans de Goede ac78288fe0 ACPI: video: Add backlight=native quirk for Dell OptiPlex 5480 AIO
Dell All In One (AIO) models released after 2017 may use a backlight
controller board connected to an UART.

In DSDT this uart port will be defined as:

   Name (_HID, "DELL0501")
   Name (_CID, EisaId ("PNP0501")

The Dell OptiPlex 5480 AIO has an ACPI device for one of its UARTs with
the above _HID + _CID. Loading the dell-uart-backlight driver fails with
the following errors:

[   18.261353] dell_uart_backlight serial0-0: Timed out waiting for response.
[   18.261356] dell_uart_backlight serial0-0: error -ETIMEDOUT: getting firmware version
[   18.261359] dell_uart_backlight serial0-0: probe with driver dell_uart_backlight failed with error -110

Indicating that there is no backlight controller board attached to
the UART, while the GPU's native backlight control method does work.

Add a quirk to use the GPU's native backlight control method on this model.

Fixes: cd8e468efb ("ACPI: video: Add Dell UART backlight controller detection")
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patch.msgid.link/20240918153849.37221-1-hdegoede@redhat.com
[ rjw: Changelog edit ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2024-10-01 20:51:26 +02:00

28 KiB