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authorZwane Mwaikambo <zwane@infradead.org>2007-04-02 12:14:12 +0200
committerAndi Kleen <andi@basil.nowhere.org>2007-04-02 12:14:12 +0200
commita369a7100da3b4f5c2269be25160653d2c7013fc (patch)
treef2215644e972ad89a93dabfd6106d4308be7d893 /arch/x86_64
parent0fb2ebfcb5f0b1916ed5ff260ec953ef616fec7c (diff)
[PATCH] x86: Don't probe for DDC on VBE1.2
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 <zwane@infradead.org> Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/x86_64')
-rw-r--r--arch/x86_64/boot/video.S14
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/x86_64/boot/video.S b/arch/x86_64/boot/video.S
index d6ff88f3513..6090516c9c7 100644
--- a/arch/x86_64/boot/video.S
+++ b/arch/x86_64/boot/video.S
@@ -571,6 +571,16 @@ setr1: lodsw
jmp _m_s
check_vesa:
+#ifdef CONFIG_FIRMWARE_EDID
+ leaw modelist+1024, %di
+ movw $0x4f00, %ax
+ int $0x10
+ cmpw $0x004f, %ax
+ jnz setbad
+
+ movw 4(%di), %ax
+ movw %ax, vbe_version
+#endif
leaw modelist+1024, %di
subb $VIDEO_FIRST_VESA>>8, %bh
movw %bx, %cx # Get mode information structure
@@ -1945,6 +1955,9 @@ store_edid:
rep
stosl
+ cmpw $0x0200, vbe_version # only do EDID on >= VBE2.0
+ jl no_edid
+
pushw %es # save ES
xorw %di, %di # Report Capability
pushw %di
@@ -1987,6 +2000,7 @@ do_restore: .byte 0 # Screen contents altered during mode change
svga_prefix: .byte VIDEO_FIRST_BIOS>>8 # Default prefix for BIOS modes
graphic_mode: .byte 0 # Graphic mode with a linear frame buffer
dac_size: .byte 6 # DAC bit depth
+vbe_version: .word 0 # VBE bios version
# Status messages
keymsg: .ascii "Press <RETURN> to see video modes available, "