i915: Fix opregion notifications

opregion-based platforms will send ACPI video event 0x80 for a range of
notification types for legacy compatibility. This is interpreted as a
display switch event, which may not be appropriate in the circumstances.
When we receive such an event we should make sure that the platform is
genuinely requesting a display switch before passing that event through
to userspace.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Tested-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index db39e9e607d8..ada4b4d9bdc8 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -46,7 +46,6 @@
 
 #define PREFIX "ACPI: "
 
-#define ACPI_VIDEO_CLASS                "video"
 #define ACPI_VIDEO_BUS_NAME             "Video Bus"
 #define ACPI_VIDEO_DEVICE_NAME          "Video Device"
 #define ACPI_VIDEO_NOTIFY_SWITCH        0x80
@@ -1445,7 +1444,8 @@ static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
         case ACPI_VIDEO_NOTIFY_SWITCH:  /* User requested a switch,
                                          * most likely via hotkey. */
                 acpi_bus_generate_proc_event(device, event, 0);
-                keycode = KEY_SWITCHVIDEOMODE;
+                if (!acpi_notifier_call_chain(device, event, 0))
+                        keycode = KEY_SWITCHVIDEOMODE;
                 break;
 
         case ACPI_VIDEO_NOTIFY_PROBE:   /* User plugged in or removed a video
@@ -1475,7 +1475,8 @@ static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
                 break;
         }
 
-        acpi_notifier_call_chain(device, event, 0);
+        if (event != ACPI_VIDEO_NOTIFY_SWITCH)
+                acpi_notifier_call_chain(device, event, 0);
 
         if (keycode) {
                 input_report_key(input, keycode, 1);