From ac78288fe062b64e45a479eaae74aaaafcc8ecdd Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Wed, 18 Sep 2024 17:38:49 +0200 Subject: [PATCH] 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: cd8e468efb4f ("ACPI: video: Add Dell UART backlight controller detection") Cc: All applicable Signed-off-by: Hans de Goede Link: https://patch.msgid.link/20240918153849.37221-1-hdegoede@redhat.com [ rjw: Changelog edit ] Signed-off-by: Rafael J. Wysocki --- drivers/acpi/video_detect.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c index b70e84e8049a..015bd8e66c1c 100644 --- a/drivers/acpi/video_detect.c +++ b/drivers/acpi/video_detect.c @@ -844,6 +844,15 @@ static const struct dmi_system_id video_detect_dmi_table[] = { * controller board in their ACPI tables (and may even have one), but * which need native backlight control nevertheless. */ + { + /* https://github.com/zabbly/linux/issues/26 */ + .callback = video_detect_force_native, + /* Dell OptiPlex 5480 AIO */ + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), + DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 5480 AIO"), + }, + }, { /* https://bugzilla.redhat.com/show_bug.cgi?id=2303936 */ .callback = video_detect_force_native,