linux-kernel - Re: [PATCH] Don't probe for DDC on VBE1.2

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Message-id: <Pine.LNX.4.64.0702160500210.31650@montezuma.fsmlabs.com>
Date:	Fri, 16 Feb 2007 06:39:45 -0800 (PST)
From:	Zwane Mwaikambo <zwane@...radead.org>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Linux Kernel <linux-kernel@...r.kernel.org>,
	Andi Kleen <ak@...e.de>, Tobias Hain <tobias.hain@....de>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH] Don't probe for DDC on VBE1.2

On Thu, 15 Feb 2007, Andrew Morton wrote:

> It's not an X problem - the screen is black immediately upon loading the
> kernel.
> 
> But I guess you knew that and you're just after display info:
> http://userweb.kernel.org/~akpm/Xorg.0.log.txt

Thanks, the X log told me your VBE version. I tried to reproduce it on my 
thinkpad which seems to have a very similar video setup to no avail, Could 
you test the following on the VAIO? If this isn't the case, i suspect i'm 
corrupting your modelist.

P.s. Thanks for the vga=0x263!

Index: linux-2.6.20-mm1/arch/i386/boot/video.S
===================================================================
RCS file: /home/cvsroot/linux-2.6.20-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-mm1/arch/i386/boot/video.S	15 Feb 2007 17:35:57 -0000	1.1.1.1
+++ linux-2.6.20-mm1/arch/i386/boot/video.S	16 Feb 2007 12:58:20 -0000
@@ -1945,6 +1945,25 @@ store_edid:
 	rep
 	stosl
 
+	pushw	%es
+	pushw	%ds
+	popw	%es
+	leaw	modelist+1024, %di
+	movw    $0x02b3, %ax
+	movw    %ax, (%di)
+	movw    $0x9d4a, %ax
+	movw    %ax, 2(%di)                     # set signature to "vbe2"
+
+	movw	$0x4f00, %ax
+	int	$0x10
+	popw	%es
+
+	cmpw	$0x004f, %ax
+	jne	no_edid
+
+	cmpw	$0x0200, 4(%di)			# only do EDID on >= VBE2.0
+	jl	no_edid
+
 	pushw   %es				# save ES
 	xorw    %di, %di                        # Report Capability
 	pushw   %di
Index: linux-2.6.20-mm1/arch/x86_64/boot/video.S
===================================================================
RCS file: /home/cvsroot/linux-2.6.20-mm1/arch/x86_64/boot/video.S,v
retrieving revision 1.1.1.1
diff -u -p -B -r1.1.1.1 video.S
--- linux-2.6.20-mm1/arch/x86_64/boot/video.S	15 Feb 2007 17:36:18 -0000	1.1.1.1
+++ linux-2.6.20-mm1/arch/x86_64/boot/video.S	16 Feb 2007 12:57:57 -0000
@@ -1945,6 +1945,25 @@ store_edid:
 	rep
 	stosl
 
+	pushw	%es
+	pushw	%ds
+	popw	%es
+	leaw	modelist+1024, %di
+	movw    $0x02b3, %ax
+	movw    %ax, (%di)
+	movw    $0x9d4a, %ax
+	movw    %ax, 2(%di)                     # set signature to "vbe2"
+
+	movw	$0x4f00, %ax
+	int	$0x10
+	popw	%es
+
+	cmpw	$0x004f, %ax
+	jne	no_edid
+
+	cmpw	$0x0200, 4(%di)			# only do EDID on >= VBE2.0
+	jl	no_edid
+
 	pushw   %es				# save ES
 	xorw    %di, %di                        # Report Capability
 	pushw   %di
-
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