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authorH. Peter Anvin <hpa@zytor.com>2007-09-13 23:16:37 +0200
committerH. Peter Anvin <hpa@zytor.com>2007-09-20 20:06:58 +0200
commit91c4b8cb5ab8cc3e8352739e35699c0487a6b6f3 (patch)
treed0a73e97ddb5c4ab8de7d5cb89517ff7f29f467f /arch/i386
parent[x86 setup] Present the canonical video mode number to the kernel (diff)
downloadlinux-91c4b8cb5ab8cc3e8352739e35699c0487a6b6f3.tar.xz
linux-91c4b8cb5ab8cc3e8352739e35699c0487a6b6f3.zip
[acpi] Correct the decoding of video mode numbers in wakeup.S
wakeup.S looks at the video mode number from the setup header and looks to see if it is a VESA mode. Unfortunately, the decoding is done incorrectly and it will attempt to frob the VESA BIOS for any mode number 0x0200 or larger. Correct this, and remove a bunch of #if 0'd code. Massive thanks to Jeff Chua for reporting the bug, and suffering though a large number of experiments in order to track this problem down. Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/i386')
-rw-r--r--arch/i386/kernel/acpi/wakeup.S41
1 files changed, 10 insertions, 31 deletions
diff --git a/arch/i386/kernel/acpi/wakeup.S b/arch/i386/kernel/acpi/wakeup.S
index ed0a0f2c1597..f22ba8534d26 100644
--- a/arch/i386/kernel/acpi/wakeup.S
+++ b/arch/i386/kernel/acpi/wakeup.S
@@ -151,51 +151,30 @@ bogus_real_magic:
#define VIDEO_FIRST_V7 0x0900
# Setting of user mode (AX=mode ID) => CF=success
+
+# For now, we only handle VESA modes (0x0200..0x03ff). To handle other
+# modes, we should probably compile in the video code from the boot
+# directory.
mode_set:
movw %ax, %bx
-#if 0
- cmpb $0xff, %ah
- jz setalias
-
- testb $VIDEO_RECALC>>8, %ah
- jnz _setrec
-
- cmpb $VIDEO_FIRST_RESOLUTION>>8, %ah
- jnc setres
-
- cmpb $VIDEO_FIRST_SPECIAL>>8, %ah
- jz setspc
-
- cmpb $VIDEO_FIRST_V7>>8, %ah
- jz setv7
-#endif
-
- cmpb $VIDEO_FIRST_VESA>>8, %ah
- jnc check_vesa
-#if 0
- orb %ah, %ah
- jz setmenu
-#endif
-
- decb %ah
-# jz setbios Add bios modes later
+ subb $VIDEO_FIRST_VESA>>8, %bh
+ cmpb $2, %bh
+ jb check_vesa
-setbad: clc
+setbad:
+ clc
ret
check_vesa:
- subb $VIDEO_FIRST_VESA>>8, %bh
orw $0x4000, %bx # Use linear frame buffer
movw $0x4f02, %ax # VESA BIOS mode set call
int $0x10
cmpw $0x004f, %ax # AL=4f if implemented
- jnz _setbad # AH=0 if OK
+ jnz setbad # AH=0 if OK
stc
ret
-_setbad: jmp setbad
-
.code32
ALIGN