[PATCH] fbdev: Firmware EDID fixes

- make firmware edid independent from framebuffer (No need to choose
  framebuffer just to disable this option

- enable this option in X86_64

- check if VBE/DDC function is implemented before calling actual function

Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/arch/x86_64/boot/video.S b/arch/x86_64/boot/video.S
index 32327bb37aff..2aa565c136e5 100644
--- a/arch/x86_64/boot/video.S
+++ b/arch/x86_64/boot/video.S
@@ -1929,6 +1929,7 @@ skip10:	movb	%ah, %al
         ret
 
 store_edid:
+#ifdef CONFIG_FIRMWARE_EDID
         pushw   %es                             # just save all registers
         pushw   %ax
         pushw   %bx
@@ -1946,6 +1947,22 @@ store_edid:
         rep
         stosl
 
+        pushw   %es                             # save ES
+        xorw    %di, %di                        # Report Capability
+        pushw   %di
+        popw    %es                             # ES:DI must be 0:0
+        movw    $0x4f15, %ax
+        xorw    %bx, %bx
+        xorw    %cx, %cx
+        int     $0x10
+        popw    %es                             # restore ES
+
+        cmpb    $0x00, %ah                      # call successful
+        jne     no_edid
+
+        cmpb    $0x4f, %al                      # function supported
+        jne     no_edid
+
         movw    $0x4f15, %ax                    # do VBE/DDC
         movw    $0x01, %bx
         movw    $0x00, %cx
@@ -1953,12 +1970,14 @@ store_edid:
         movw    $0x140, %di
         int     $0x10
 
+no_edid:
         popw    %di                             # restore all registers
         popw    %dx
         popw    %cx
         popw    %bx
         popw    %ax
         popw    %es
+#endif
         ret
 
 # VIDEO_SELECT-only variables