The Xiaomi Mi Pad 2 is a Cherry Trail based x86 tablet which does not
use the i915's driver backlight control support:
i915 0000:00:02.0: [drm:intel_panel_setup_backlight [i915]] no backlight present per VBT
Like all Cherry Trail devices the ACPI tables on the Xiaomi Mi Pad 2
contain a broken ACPI-video implementation which causes 6 different
acpi_video backlights to get registered when used.
The lack of the i915 driver registering a BACKLIGHT_RAW (aka native) type
backlight causes acpi_video_get_backlight_type() to pick the broken
acpi_video backlight code as the backlight driver to use.
There actually is a separate lp8556 backlight controller connected
over I2C which gets registered as a BACKLIGHT_PLATFORM (aka vendor).
Add a quirk to force acpi_video_get_backlight_type() to return
acpi_backlight_vendor, so that the broken acpi_video backlight
interfaces do not get registered.
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
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 7a1f8e823208..068e393ea0c6 100644
--- a/drivers/acpi/video_detect.c
+++ b/drivers/acpi/video_detect.c
@@ -154,6 +154,14 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
DMI_MATCH(DMI_PRODUCT_NAME, "VPCEH3U1E"),
},
},
+ {
+ .callback = video_detect_force_vendor,
+ /* Xiaomi Mi Pad 2 */
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "Xiaomi Inc"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "Mipad2"),
+ },
+ },
/*
* These models have a working acpi_video backlight control, and using
--
2.31.1
