On Thu, 15 Feb 2007 08:29:49 -0800 (PST) Zwane Mwaikambo <[EMAIL PROTECTED]> 
wrote:

> VBE1.2 doesn't support function 15h (DDC) resulting in a 'hang' whilst
> uncompressing kernel with some video cards. Make sure we check VBE version 
> before fiddling around with DDC.
> 
> http://bugzilla.kernel.org/show_bug.cgi?id=1458
> 
> Opened: 2003-10-30 09:12 Last update: 2007-02-13 22:03
> 
> :(
> 
> Much thanks to Tobias Hain for help in testing and investigating the bug. 
> Tested on;
> 
> i386, Chips & Technologies 65548 VESA VBE 1.2
> CONFIG_VIDEO_SELECT=Y
> CONFIG_FIRMWARE_EDID=Y
> 
> Untested on x86_64.
> 
> Signed-off-by: Zwane Mwaikambo <[EMAIL PROTECTED]>
> 
> Index: linux-2.6.20-rc6-mm1/arch/i386/boot/video.S
> ===================================================================
> RCS file: /home/cvsroot/linux-2.6.20-rc6-mm1/arch/i386/boot/video.S,v
> retrieving revision 1.1.1.1
> diff -u -p -B -r1.1.1.1 video.S
> --- linux-2.6.20-rc6-mm1/arch/i386/boot/video.S       30 Jan 2007 05:28:31 
> -0000      1.1.1.1
> +++ linux-2.6.20-rc6-mm1/arch/i386/boot/video.S       15 Feb 2007 16:27:32 
> -0000
> @@ -1945,6 +1945,20 @@ store_edid:
>       rep
>       stosl
>  
> +     pushw   %es
> +     pushw   %ds
> +     popw    %es
> +     leaw    modelist+1024, %di
> +     movw    $0x4f00, %ax
> +     int     $0x10
> +     popw    %es
> +
> +     cmpw    $0x004f, %ax
> +     jne     no_edid
> +
> +     cmpw    $0x0102, 4(%di)                 # only do EDID on > 1.2
> +     je      no_edid
> +
>       pushw   %es                             # save ES
>       xorw    %di, %di                        # Report Capability
>       pushw   %di

This makes the long-suffering-but-vigorously-defended Vaio come up with a
black display.  Everything's working OK otherwise.  Sort of a Black Screen
of Life.  I wouldn't call it an improvement though.
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