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authorAaron Lu <aaron.lu@intel.com>2014-09-30 14:10:17 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-09-30 20:49:19 +0200
commit0b8db271f1592e118feef7300f6da85bea9366da (patch)
tree1701b43f8b4b9a557719b753d04797917390085b /drivers/acpi/video.c
parenta11d342fb89aedec5003d116e7427d43cbba714d (diff)
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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>
Diffstat (limited to 'drivers/acpi/video.c')
-rw-r--r--drivers/acpi/video.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 5a98e1db68c0..015b93df5201 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -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;