-stable review patch. If anyone has any objections, please let us know.
------------------
From: Zwane Mwaikambo <[email protected]>
[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 <[email protected]>
Signed-off-by: Andi Kleen <[email protected]>
Cc: Chuck Ebbert <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/i386/boot/video.S | 14 ++++++++++++++
arch/x86_64/boot/video.S | 14 ++++++++++++++
2 files changed, 28 insertions(+)
--- a/arch/i386/boot/video.S
+++ b/arch/i386/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 al
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, "
--- 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 al
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, "
--
-
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