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>
#define VIDEO_FIRST_V7 0x0900
# Setting of user mode (AX=mode ID) => CF=success
#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.
-#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
- 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
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
testl $2, realmode_flags - wakeup_code
jz 1f
mov video_mode - wakeup_code, %ax
testl $2, realmode_flags - wakeup_code
jz 1f
mov video_mode - wakeup_code, %ax
#define VIDEO_FIRST_V7 0x0900
# Setting of user mode (AX=mode ID) => CF=success
#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.
-#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
-check_vesaa:
- 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
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
wakeup_stack_begin: # Stack grows down
.org 0xff0
wakeup_stack_begin: # Stack grows down
.org 0xff0