ACPI: video: Loosen strictness of video bus detection code
Stefan Bader [Fri, 21 Aug 2009 09:03:05 +0000 (11:03 +0200)]
BugLink: http://bugs.launchpad.net/bugs/333386

Currently a video bus device must (beside other criteria) define _DOD and
_DOS methods to be considered a video device.
Some broken BIOSes prevented working backlight control by only defining both
for one (non-existing bus) and only _DOD for the rest. With this patch in
place the other bus definitions were considered too and backlight control
started to work again.

Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/video.c
drivers/acpi/video_detect.c

index f6e54bf..64e3c58 100644 (file)
@@ -1109,7 +1109,12 @@ static int acpi_video_bus_check(struct acpi_video_bus *video)
         */
 
        /* Does this device support video switching? */
-       if (video->cap._DOS) {
+       if (video->cap._DOS || video->cap._DOD) {
+               if (!video->cap._DOS) {
+                       printk(KERN_WARNING FW_BUG
+                               "ACPI(%s) defines _DOD but not _DOS\n",
+                               acpi_device_bid(video->device));
+               }
                video->flags.multihead = 1;
                status = 0;
        }
index 7032f25..575593a 100644 (file)
@@ -84,7 +84,7 @@ long acpi_is_video_device(struct acpi_device *device)
                return 0;
 
        /* Does this device able to support video switching ? */
-       if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOD", &h_dummy)) &&
+       if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOD", &h_dummy)) ||
            ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOS", &h_dummy)))
                video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;