[PATCH 11/12] ACPI video: allow events handlers to veto the keypress

Alex Hung alex.hung at canonical.com
Tue Feb 5 19:06:32 UTC 2013

From: Luca Tettamanti <kronos.it at gmail.com>

The standard video events may be overloaded for device specific
purposes. For example AMD ACPI interface overloads
ACPI_VIDEO_NOTIFY_PROBE (0x81) to signal AMD-specific events. In such
cases we don't want to send the keypress (KEY_SWITCHVIDEOMODE) to the
userspace because the user did not press the mode switch key (the
spurious keypress confuses the DE which usually changes the
display configuration and messes up a dual-screen setup).
This patch gives the handlers the chance to examine the event and
block the keypress if the event is device specific.
v2: refactor as suggested by Zhang Rui <rui.zhang at intel.com>

Signed-off-by: Luca Tettamanti <kronos.it at gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
 drivers/acpi/video.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 1e0a9e1..f94d4c8 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -1448,8 +1448,7 @@ 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);
-		if (!acpi_notifier_call_chain(device, event, 0))
 	case ACPI_VIDEO_NOTIFY_PROBE:	/* User plugged in or removed a video
@@ -1479,8 +1478,9 @@ static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
-		acpi_notifier_call_chain(device, event, 0);
+	if (acpi_notifier_call_chain(device, event, 0))
+		/* Something vetoed the keypress. */
+		keycode = 0;
 	if (keycode) {
 		input_report_key(input, keycode, 1);

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