Refine SCREEN_INFO sanity check for vgacon initialization

Refine SCREEN_INFO sanity check for vgacon initialization.

Checking video mode field only to see whenever SCREEN_INFO is
initialized is not enougth, in some cases it is zero although
a vga card is present.  Lets additionally check cols and lines.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <ak@suse.de>
Cc: Alan <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index 2460b82a1d93..f46fe95f69fb 100644
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -368,9 +368,14 @@ static const char *vgacon_startup(void)
 #endif
         }
 
+        /* SCREEN_INFO initialized? */
+        if ((ORIG_VIDEO_MODE  == 0) &&
+            (ORIG_VIDEO_LINES == 0) &&
+            (ORIG_VIDEO_COLS  == 0))
+                goto no_vga;
+
         /* VGA16 modes are not handled by VGACON */
-        if ((ORIG_VIDEO_MODE == 0x00) ||        /* SCREEN_INFO not initialized */
-            (ORIG_VIDEO_MODE == 0x0D) ||        /* 320x200/4 */
+        if ((ORIG_VIDEO_MODE == 0x0D) ||        /* 320x200/4 */
             (ORIG_VIDEO_MODE == 0x0E) ||        /* 640x200/4 */
             (ORIG_VIDEO_MODE == 0x10) ||        /* 640x350/4 */
             (ORIG_VIDEO_MODE == 0x12) ||        /* 640x480/4 */