If the firmware has declared more than 8 video output devices, and the one that control the internal panel's backlight is listed after the first 8 output devices, the _DOD will not include it due to the current i915 operation region implementation. As a result, we will not create a backlight device for it while we should. Solve this problem by special case the firmware that has 8+ output devices in that if we see such a firmware, we do not test if the device is in _DOD list. The creation of the backlight device will also enable the firmware to emit events on backlight hotkey press when the acpi_osi= cmdline option is specified on those affected ASUS laptops. Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=70241 Reported-and-tested-by: Oleksij Rempel <linux@xxxxxxxxxxxxxxxx> Reported-and-tested-by: Dmitry Tunin <hanipouspilot@xxxxxxxxx> Reported-and-tested-by: Jimbo <jaime.91@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Aaron Lu <aaron.lu@xxxxxxxxx> --- drivers/acpi/video.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index 8b844931b936..c72e79d2c5ad 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -155,6 +155,7 @@ struct acpi_video_bus { u8 dos_setting; struct acpi_video_enumerated_device *attached_array; u8 attached_count; + u8 child_count; struct acpi_video_bus_cap cap; struct acpi_video_bus_flags flags; struct list_head video_device_list; @@ -1176,8 +1177,12 @@ static bool acpi_video_device_in_dod(struct acpi_video_device *device) struct acpi_video_bus *video = device->video; int i; - /* If we have a broken _DOD, no need to test */ - if (!video->attached_count) + /* + * If we have a broken _DOD or we have more than 8 output devices + * under the graphics controller node that we can't proper deal with + * in the operation region code currently, no need to test. + */ + if (!video->attached_count || video->child_count > 8) return true; for (i = 0; i < video->attached_count; i++) { @@ -1430,6 +1435,7 @@ acpi_video_bus_get_devices(struct acpi_video_bus *video, dev_err(&dev->dev, "Can't attach device\n"); break; } + video->child_count++; } return status; } -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
