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[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>
This commit is contained in:
H. Peter Anvin 2007-09-13 14:16:37 -07:00
parent 3f662b3f6e
commit 91c4b8cb5a
2 changed files with 23 additions and 65 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
arch/i386/kernel/acpi/wakeup.S
View File

@ -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
subb $VIDEO_FIRST_VESA>>8, %bh
cmpb $2, %bh
jb check_vesa
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
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

47
arch/x86_64/kernel/acpi/wakeup.S
View File

@ -81,7 +81,7 @@ wakeup_code:
testl $2, realmode_flags - wakeup_code
jz 1f
mov video_mode - wakeup_code, %ax
call mode_seta
call mode_set
1:
movw $0xb800, %ax
@ -291,52 +291,31 @@ no_longmode:
#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.
.code16
mode_seta:
mode_set:
movw %ax, %bx
#if 0
cmpb $0xff, %ah
jz setalias
subb $VIDEO_FIRST_VESA>>8, %bh
cmpb $2, %bh
jb check_vesa
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_vesaa
#if 0
orb %ah, %ah
jz setmenu
#endif
decb %ah
# jz setbios Add bios modes later
setbada: clc
setbad:
clc
ret
check_vesaa:
subb $VIDEO_FIRST_VESA>>8, %bh
check_vesa:
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 _setbada # AH=0 if OK
jnz setbad # AH=0 if OK
stc
ret
_setbada: jmp setbada
wakeup_stack_begin: # Stack grows down
.org 0xff0