ACPI video: remove output switching control

Remove the ACPI video output switching control as it never works.

With the patch applied,
ACPI video driver still catches the video output notification,
but it does nothing but raises the notification to userspace.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 4 insertions, 53 deletions

diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
index b8367612659..42d3d72dae8 100644
--- a/drivers/acpi/video_detect.c
+++ b/drivers/acpi/video_detect.c
@@ -17,15 +17,14 @@
  * capabilities the graphics cards plugged in support. The check for general
  * video capabilities will be triggered by the first caller of
  * acpi_video_get_capabilities(NULL); which will happen when the first
- * backlight (or display output) switching supporting driver calls:
+ * backlight switching supporting driver calls:
  * acpi_video_backlight_support();
  *
  * Depending on whether ACPI graphics extensions (cmp. ACPI spec Appendix B)
  * are available, video.ko should be used to handle the device.
  *
  * Otherwise vendor specific drivers like thinkpad_acpi, asus_acpi,
- * sony_acpi,... can take care about backlight brightness and display output
- * switching.
+ * sony_acpi,... can take care about backlight brightness.
  *
  * If CONFIG_ACPI_VIDEO is neither set as "compiled in" (y) nor as a module (m)
  * this file will not be compiled, acpi_video_get_capabilities() and
@@ -83,11 +82,6 @@ long acpi_is_video_device(struct acpi_device *device)
 	if (!device)
 		return 0;
 
-	/* Is this device able to support video switching ? */
-	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;
-
 	/* Is this device able to retrieve a video ROM ? */
 	if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_ROM", &h_dummy)))
 		video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
@@ -161,8 +155,6 @@ long acpi_video_get_capabilities(acpi_handle graphics_handle)
 		 *
 		 *   if (dmi_name_in_vendors("XY")) {
 		 *	acpi_video_support |=
-		 *		ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR;
-		 *	acpi_video_support |=
 		 *		ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 		 *}
 		 */
@@ -212,33 +204,8 @@ int acpi_video_backlight_support(void)
 EXPORT_SYMBOL(acpi_video_backlight_support);
 
 /*
- * Returns true if video.ko can do display output switching.
- * This does not work well/at all with binary graphics drivers
- * which disable system io ranges and do it on their own.
- */
-int acpi_video_display_switch_support(void)
-{
-	if (!acpi_video_caps_checked)
-		acpi_video_get_capabilities(NULL);
-
-	if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR)
-		return 0;
-	else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO)
-		return 1;
-
-	if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR)
-		return 0;
-	else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VIDEO)
-		return 1;
-
-	return acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING;
-}
-EXPORT_SYMBOL(acpi_video_display_switch_support);
-
-/*
- * Use acpi_display_output=vendor/video or acpi_backlight=vendor/video
- * To force that backlight or display output switching is processed by vendor
- * specific acpi drivers or video.ko driver.
+ * Use acpi_backlight=vendor/video to force that backlight switching
+ * is processed by vendor specific acpi drivers or video.ko driver.
  */
 static int __init acpi_backlight(char *str)
 {
@@ -255,19 +222,3 @@ static int __init acpi_backlight(char *str)
 	return 1;
 }
 __setup("acpi_backlight=", acpi_backlight);
-
-static int __init acpi_display_output(char *str)
-{
-	if (str == NULL || *str == '\0')
-		return 1;
-	else {
-		if (!strcmp("vendor", str))
-			acpi_video_support |=
-				ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR;
-		if (!strcmp("video", str))
-			acpi_video_support |=
-				ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO;
-	}
-	return 1;
-}
-__setup("acpi_display_output=", acpi_display_output);