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* [PATCH] ACPI / video: check _DOD list when creating backlight device
@ 2014-09-30  6:10 Aaron Lu
  2014-09-30 20:18 ` Rafael J. Wysocki
  0 siblings, 1 reply; 10+ messages in thread
From: Aaron Lu @ 2014-09-30  6:10 UTC (permalink / raw)
  To: Rafael J. Wysocki, ntrrgc; +Cc: ACPI Devel Mailing List

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.

Buglink: 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>
---
 drivers/acpi/video.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 7285c7f9a935..807a88a0f394 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -1154,6 +1154,23 @@ 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
@@ -1593,6 +1610,15 @@ 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;
-- 
1.9.3


^ permalink raw reply related	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2014-12-03  2:04 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-09-30  6:10 [PATCH] ACPI / video: check _DOD list when creating backlight device Aaron Lu
2014-09-30 20:18 ` Rafael J. Wysocki
2014-10-09  8:27   ` Aaron Lu
2014-11-28  9:59     ` Brian Norris
2014-11-28 11:55       ` Aaron Lu
2014-11-28 17:18         ` Brian Norris
2014-11-29 13:01           ` Aaron Lu
2014-11-29 17:34             ` Brian Norris
2014-11-30  1:14               ` [PATCH] ACPI / video: update the condition to check if a device is in _DOD list Aaron Lu
2014-12-03  2:25                 ` Rafael J. Wysocki

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