[PATCH] vgacon: checking for efi machine

From: Yannick Heneault
Date: Thu Jan 06 2011 - 11:39:25 EST

It seems there is a small problem of VGA palette corruption on EFI machine. When the kernel initializes the architecture, it checks if themachine is a EFI machine and assumes that a VGA console can exist. When it initialize the console in vgacon_startup it checks if itcan really use the VGA console. I think this is where a check ismissing. Currently, the function can fail if a VESA boot mode isdetected but not if a EFI boot mode was used. Thus, the function vgacon_startup doesn't fail and initialize thevideo card for a real VGA mode. This function change the first 16entries of the VGA palette. When the efifb driver kick-in, the paletteis not restored to default ramp value, thus the 16 first entry remain ina modified state. The following patch prevent this corruption.

Signed-off-by: Yannick Heneault<yheneaul@xxxxxxxxxx>
diff -Nur linux-2.6.37-ori/drivers/video/console/vgacon.c linux-2.6.37/drivers/video/console/vgacon.c
--- linux-2.6.37-ori/drivers/video/console/vgacon.c 2011-01-04 19:50:19.000000000 -0500
+++ linux-2.6.37/drivers/video/console/vgacon.c 2011-01-06 10:38:24.713590593 -0500
@@ -375,7 +375,8 @@
u16 saved1, saved2;
volatile u16 *p;

- if (screen_info.orig_video_isVGA == VIDEO_TYPE_VLFB) {
+ if (screen_info.orig_video_isVGA == VIDEO_TYPE_VLFB ||
+ screen_info.orig_video_isVGA == VIDEO_TYPE_EFI) {
conswitchp =&dummy_con;

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/