Commit 91c4b8cb authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

[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: default avatarH. Peter Anvin <hpa@zytor.com>
parent 3f662b3f

arch/i386/kernel/acpi/wakeup.S

+10 −31
Original line number Diff line number Diff line
@@ -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

arch/x86_64/kernel/acpi/wakeup.S

+13 −34
Original line number Diff line number Diff line
@@ -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



	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

	subb	$VIDEO_FIRST_VESA>>8, %bh

	cmpb	$2, %bh

	jb	check_vesa



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

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