efifb: dmi set video type

The current logic for dmi matching in efifb does not allow efifb to load
on all hardware that we can dmi match for.

For a real world example, boot with elilo (3.7 or 3.8 vanilla) and on a
Apple (MacBook) and EFI framebuffer driver will not load (you will have no
video).  This specific hardware is efi v1.10, so we have UGA and not GOP.
Without special bootloader magic (i.e.  extra elilo patches for UGA
graphics detection) no screen info will be passed to the kernel and as a
result efifb will not load.

This patch allows the dmi match to happen by moving it to earlier in
efifb_init, and sets the video type (in set_system) so that efifb can load
when we have a valid dmi match and already know the specifics of the
hardware.

Without this patch the efifb driver will fail to load in the event screen
info is not found and passed in by the bootloader, being that we will
never get to look for a dmi match.  A primary reason for matching with dmi
is because not all bootloaders detect the video info properly.  The
solution is that in the event of a dmi match, we should set
screen_info.orig_video_isVGA.  Most bootloaders fail to set screen info on
Apple hardware, and this is a big problem for people who use Apple
hardware.

Tested on a MacBook SantaRosa with elilo-3.8 (vanilla) and resolves the
issue, the dmi match now works, EFI framebuffer now loads and video works.

Signed-off-by: Brian Maly <bmaly@redhat.com>
Acked-by: Huang Ying <ying.huang@intel.com>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Cc: Chandramouli Narayanan <mouli@linux.intel.com>
Acked-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/video/efifb.c b/drivers/video/efifb.c
index daf9b81878a4..0c5b9a9fd56f 100644
--- a/drivers/video/efifb.c
+++ b/drivers/video/efifb.c
@@ -129,6 +129,8 @@ static int set_system(const struct dmi_system_id *id)
                 screen_info.lfb_width = info->width;
         if (screen_info.lfb_height == 0)
                 screen_info.lfb_height = info->height;
+        if (screen_info.orig_video_isVGA == 0)
+                screen_info.orig_video_isVGA = VIDEO_TYPE_EFI;
 
         return 0;
 }
@@ -374,9 +376,10 @@ static int __init efifb_init(void)
         int ret;
         char *option = NULL;
 
+        dmi_check_system(dmi_system_table);
+
         if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
                 return -ENODEV;
-        dmi_check_system(dmi_system_table);
 
         if (fb_get_options("efifb", &option))
                 return -ENODEV;