DRM: add mode setting support

Add mode setting support to the DRM layer.

This is a fairly big chunk of work that allows DRM drivers to provide
full output control and configuration capabilities to userspace.  It was
motivated by several factors:
  - the fb layer's APIs aren't suited for anything but simple
    configurations
  - coordination between the fb layer, DRM layer, and various userspace
    drivers is poor to non-existent (radeonfb excepted)
  - user level mode setting drivers makes displaying panic & oops
    messages more difficult
  - suspend/resume of graphics state is possible in many more
    configurations with kernel level support

This commit just adds the core DRM part of the mode setting APIs.
Driver specific commits using these new structure and APIs will follow.

Co-authors: Jesse Barnes <jbarnes@virtuousgeek.org>, Jakob Bornecrantz <jakob@tungstengraphics.com>
Contributors: Alan Hourihane <alanh@tungstengraphics.com>, Maarten Maathuis <madman2003@gmail.com>

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index 448d209a0bf2..e6210725b9ab 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -112,6 +112,23 @@ static int 		vga_video_font_height;
 static int 		vga_scan_lines		__read_mostly;
 static unsigned int 	vga_rolled_over;
 
+int vgacon_text_mode_force = 0;
+
+bool vgacon_text_force(void)
+{
+	return vgacon_text_mode_force ? true : false;
+}
+EXPORT_SYMBOL(vgacon_text_force);
+
+static int __init text_mode(char *str)
+{
+	vgacon_text_mode_force = 1;
+	return 1;
+}
+
+/* force text mode - used by kernel modesetting */
+__setup("nomodeset", text_mode);
+
 static int __init no_scroll(char *str)
 {
 	/*