Commit 0b8db271 authored Sep 30, 2014 by Aaron Lu Committed by Rafael J. Wysocki Sep 30, 2014

ACPI / video: check _DOD list when creating backlight devices

The _DOD method lists which video output device is currently attached so
we should only care about them and ignore others. An user recently
reported that there are two acpi_video interfaces appeared on his system
and one of them doesn't work. From the acpidump, it is found that there
are more than one video output devices that have _BCM control method but
the _DOD lists only one of them. So this patch checks if the video output
device is in the _DOD list and will not create backlight device if it is
not in the list. Also, we consider the broken _DOD case(reflected by the
video->attached_count is 0) and do not change behaviour for those broken
_DOD systems.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=84111


Reported-and-tested-by:  <ntrrgc@gmail.com>
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

parent a11d342f

drivers/acpi/video.c

+26 −0

Original line number	Diff line number	Diff line
		@@ -1146,6 +1146,23 @@ acpi_video_device_bind(struct acpi_video_bus *video,
		}
		}

		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)
		return true;

		for (i = 0; i < video->attached_count; i++) {
		if (video->attached_array[i].bind_info == device)
		return true;
		}

		return false;
		}

		/*
		* Arg:
		* video : video bus device
		@@ -1585,6 +1602,15 @@ static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
		static int count;
		char *name;

		/*
		* Do not create backlight device for video output
		* device that is not in the enumerated list.
		*/
		if (!acpi_video_device_in_dod(device)) {
		dev_dbg(&device->dev->dev, "not in _DOD list, ignore\n");
		return;
		}

		result = acpi_video_init_brightness(device);
		if (result)
		return;

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