ACPI: video: Add backlight=native quirk for Dell OptiPlex 7760 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 7760 AIO has an ACPI device for one if its UARTs with
the above _HID + _CID. Loading the dell-uart-backlight driver shows that
there actually is a backlight controller board attached to the UART,
which reports a firmware version of "G&MX01-V15".

But the backlight controller board does not actually control the backlight
brightness and 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: 484bae9e4d6a ("platform/x86: Add new Dell UART backlight driver")
Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2303936
Cc: All applicable <[email protected]>
Signed-off-by: Hans de Goede <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Rafael J. Wysocki <[email protected]>

diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
index e509dcbf309064423d1847dfd6c6ef0710f694e1..674b9db7a1ef8b021cccf06fa8db6a21a0c0b51b 100644 (file)
--- a/drivers/acpi/video_detect.c
+++ b/drivers/acpi/video_detect.c
@@ -823,6 +823,21 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
                },
        },
 
+       /*
+        * Dell AIO (All in Ones) which advertise an UART attached backlight
+        * controller board in their ACPI tables (and may even have one), but
+        * which need native backlight control nevertheless.
+        */
+       {
+        /* https://bugzilla.redhat.com/show_bug.cgi?id=2303936 */
+        .callback = video_detect_force_native,
+        /* Dell OptiPlex 7760 AIO */
+        .matches = {
+               DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+               DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 7760 AIO"),
+               },
+       },
+
        /*
         * Models which have nvidia-ec-wmi support, but should not use it.
         * Note this indicates a likely firmware bug on these models and should