[PATCH 2/2] ACPI: video: Add backlight=native DMI quirk for HP EliteBook 8460p

[Hans de Goede]

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 at redhat.com>
---
 drivers/acpi/video_detect.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
index c660dd6f896e..3a2589917648 100644
--- a/drivers/acpi/video_detect.c
+++ b/drivers/acpi/video_detect.c
@@ -618,6 +618,14 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 		DMI_MATCH(DMI_PRODUCT_NAME, "UX303UB"),
 		},
 	},
+	{
+	 .callback = video_detect_force_native,
+	 /* HP EliteBook 8460p */
+	 .matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
+		DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook 8460p"),
+		},
+	},
 	{
 	 .callback = video_detect_force_native,
 	 /* HP Pavilion g6-1d80nr / B4U19UA */
-- 
2.39.0