- Graphics fixessyslinux-1.62-pre3

- More work on memdisk.asm
- PXELINUX: Move private options to 208 (to avoid Etherboot conflict);
  document need to force these options on the server and the associated
  problems.

6 files changed, 468 insertions, 72 deletions

diff --git a/isolinux.asm b/isolinux.asm
index 56d740ba..f3f926b4 100644
--- a/isolinux.asm
+++ b/isolinux.asm
@@ -3043,7 +3043,7 @@ use_font:
 		jne .text
 
 .graphics:
-		xor cx,bx
+		xor cx,cx
 		mov cl,bh			; CX = bytes/character
 		mov ax,480
 		div cl				; Compute char rows per screen
@@ -3052,7 +3052,7 @@ use_font:
 		mov [VidRows],al
 		mov ax,1121h			; Set user character table
 		int 10h
-		mov [VidRows], byte 79		; Always 80 bytes/line
+		mov [VidCols], byte 79		; Always 80 bytes/line
 		mov [TextPage], byte 0		; Always page 0
 		ret	; No need to call adjust_screen
 
@@ -4156,7 +4156,7 @@ vgaclearmode:
 ;		mov dx,TextColorReg	; Restore color registers
 ;		mov ax,1002h
 ;		int 10h
-
+		mov [UsingVGA], byte 0
 
 		call use_font		; Restore text font/data
 		mov byte [ScrollAttribute], 07h
diff --git a/ldlinux.asm b/ldlinux.asm
index 78329f8b..50e5e29f 100644
--- a/ldlinux.asm
+++ b/ldlinux.asm
@@ -2989,7 +2989,7 @@ use_font:
 		jne .text
 
 .graphics:
-		xor cx,bx
+		xor cx,cx
 		mov cl,bh			; CX = bytes/character
 		mov ax,480
 		div cl				; Compute char rows per screen
@@ -2998,7 +2998,7 @@ use_font:
 		mov [VidRows],al
 		mov ax,1121h			; Set user character table
 		int 10h
-		mov [VidRows], byte 79		; Always 80 bytes/line
+		mov [VidCols], byte 79		; Always 80 bytes/line
 		mov [TextPage], byte 0		; Always page 0
 		ret	; No need to call adjust_screen
 
@@ -4126,7 +4126,7 @@ vgaclearmode:
 ;		mov dx,TextColorReg	; Restore color registers
 ;		mov ax,1002h
 ;		int 10h
-
+		mov [UsingVGA], byte 0
 
 		call use_font		; Restore text font/data
 		mov byte [ScrollAttribute], 07h
diff --git a/memdisk.asm b/memdisk.asm
index aa95f9ec..a690e66b 100644
--- a/memdisk.asm
+++ b/memdisk.asm
@@ -19,10 +19,15 @@
 
 		org 0h
 
+%define SECTORSIZE_LG2	9		; log2(sector size)
+%define	SECTORSIZE	(1 << SECTORSIZE_LG2)
+
 MyStack		equ 1024
 
 		; Parameter registers definition; this is the definition
 		; of the stack frame.
+%define		P_DS		word [bp+34]
+%define		P_ES		word [bp+32]
 %define		P_EAX		dword [bp+28]
 %define		P_AX		word [bp+28]
 %define		P_AL		byte [bp+28]
@@ -86,6 +91,7 @@ Done:		; Standard routine for return
 		mov [LastStatus],ah
 		mov P_AX,ax
 		cmp ah,1
+DoneWeird:
 		setnb al		; AL <- (AH > 0) ? 1 : 0 (CF)
 		lds bx,[Stack]		; DS:BX <- Old stack pointer
 		mov [bx+4],al		; Low byte of old FLAGS -> arithmetric flags
@@ -106,38 +112,208 @@ Reset:
 		and dl,80h		; Clear all but the type bit
 		jmp far [OldInt13]
 
+Invalid:
+		mov ax,0100h		; Unsupported function
+		ret
+
+GetDriveType:
+		pop ax			; Drop return address
+		mov ah,[DriveNo]
+		shr ah,7
+		or ah,02h		; CF = 0
+		mov P_AH,ah
+		mov [LastStatus],byte 0	; Success, but AH returns a value
+		jmp short DoneWeird
+
 GetStatus:
 		mov ah,[LastStatus]	; Copy last status
 		ret
 
-CheckIfReady:
+CheckIfReady:				; These are always-successful noop functions
 Recalibrate:
-		xor ah,ah		; Always successful
+InitWithParms:
+DetectChange:
+success:
+		xor ax,ax		; Always successful
 		ret
 
 Read:
+		call setup_regs
+do_copy:
+		call bcopy
+		movzx ax,P_AL		; AH = 0, AL = transfer count
+		ret
+
 Write:
+		call setup_regs
+		xchg esi,edi
+		jmp short do_copy
+
+		; These verify one sector only
+Seek:
+		mov P_AL,1
+
+		; Verify integrity; just bounds-check
 Verify:
-Format:
+		call setup_regs		; Returns error if appropriate
+		jmp short success	
+
 GetParms:
-InitWithParms:
-Seek:
-GetDriveType:
-DetectChange:
+		; We need to get the "number of drives" from the BIOS
+		mov dl,P_DL
+		inc dl			; The drive whose number we're stealing
+		mov ah,08h
+		int 13h
+		inc dl			; Add ourselves to the count
+		mov P_DL,dl		; Drive count
+		mov P_DI,di		; Steal the diskette parameter table if applicable
+		mov ax,es
+		mov P_ES,ax
+		mov bl,[DriveType]
+		mov P_BL,bl
+		mov ax,[Cylinders]
+		dec ax			; We report the highest #, not the count
+		or ah,[Sectors]
+		xchg al,ah
+		mov P_CX,ax
+		mov al,[Heads]
+		dec al
+		mov P_DH,al
+		xor ax,ax
+		ret
 
-Invalid:
-		mov ah,01h		; Unsupported function
+		; Convert a CHS address in CX/DH into an LBA in EAX
+chstolba:
+		xor ebx,ebx
+		mov bl,cl		; Sector number
+		and bl,3Fh
+		dec bx
+		mov si,dx
+		mov ax,[Heads]
+		shr cl,6
+		xchg cl,ch		; Now CX <- cylinder number
+		mul cx			; DX:AX <- AX*CX
+		shr si,8		; SI <- head number
+		add ax,si
+		adc dx,byte 0
+		shl edx,16
+		or eax,edx
+		mul dword [Sectors]
+		add eax,ebx
+		ret
+
+bcopy:
+		; Do something here
+
+		; Set up registers as for a "Read", and compares against disk size
+setup_regs:
+		call chstolba
+		movzx edi,P_BX		; Get linear address of target buffer
+		movzx ecx,P_ES
+		shr ecx,4
+		add edi,ecx
+		movzx ecx,P_AL
+		lea ebx,[eax+ecx]
+		mov esi,eax
+		shr esi,SECTORSIZE_LG2
+		add esi,[DiskBuf]
+		cmp ebx,[DiskSize]
+		jae .overrun
 		ret
 
+.overrun:	pop ax			; Drop return address
+		mov ax,0400h		; Sector not found
+		ret
+
+int15_e820:
+		cmp edx,534D4150h
+		jne near oldint15
+		cmp ecx,20		; Need 20 bytes
+		jb err86
+		push edx		; "SMAP"
+		push esi
+		push edi
+		and ebx,ebx
+		jne .renew
+		mov ebx,[E820Table]
+.renew:		mov esi,ebx
+		xor edi,edi
+		mov di,cs
+		shr di,4
+		add edi,E820Buf
+		mov ecx,24/4
+		call bcopy
+		add ebx, byte 12
+		pop edi
+		pop esi
+		mov eax,[cs:E820Buf]
+		mov [es:di],eax
+		mov eax,[cs:E820Buf+4]
+		mov [es:di+4],eax
+		mov eax,[cs:E820Buf+12]
+		mov [es:di+8],eax
+		mov eax,[cs:E820Buf+16]
+		mov [es:di+12],eax
+		mov eax,[cs:E820Buf+8]
+		mov [es:di+16],eax
+		cmp dword [cs:E820Buf+20], byte -1
+		jne .notdone
+		xor ebx,ebx		; Done with table
+.notdone:
+		pop eax			; "SMAP"
+		mov ecx,20		; Bytes loaded
+int15_success:
+		mov byte [bp+12], 02h	; Clear CF
+		pop bp
+		iret
+
+err86:
+		mov byte [bp+12], 03h	; Set CF
+		mov ah,86h
+		pop bp
+		iret
+
+Int15Start:
+		push bp
+		mov bp,sp
+		cmp ax,0E820h
+		je near int15_e820
+		cmp ax,0E801h
+		je int15_e801
+		cmp ax,0E881h
+		je int15_e881
+		cmp ah,88h
+		je int15_88
+oldint15:	pop bp
+		jmp far [OldInt15]
+		
+int15_e801:
+		mov ax,[cs:Mem1MB]
+		mov cx,ax
+		mov bx,[cs:Mem16MB]
+		mov dx,ax
+		jmp short int15_success
+
+int15_e881:
+		mov eax,[cs:Mem1MB]
+		mov ecx,eax
+		mov ebx,[cs:Mem16MB]
+		mov edx,eax
+		jmp short int15_success
+
+int15_88:
+		mov ax,[cs:MemInt1588]
+		jmp short int15_success
+
 		section .data
 Int13Funcs	dw Reset		; 00h - RESET
 		dw GetStatus		; 01h - GET STATUS
 		dw Read			; 02h - READ
 		dw Write		; 03h - WRITE
 		dw Verify		; 04h - VERIFY
-		dw Format		; 05h - FORMAT TRACK
-		dw Format		; 06h - FORMAT TRACK AND SET BAD FLAGS
-		dw Format		; 07h - FORMAT DRIVE AT TRACK
+		dw Invalid		; 05h - FORMAT TRACK
+		dw Invalid		; 06h - FORMAT TRACK AND SET BAD FLAGS
+		dw Invalid		; 07h - FORMAT DRIVE AT TRACK
 		dw GetParms		; 08h - GET PARAMETERS
 		dw InitWithParms	; 09h - INITIALIZE CONTROLLER WITH DRIVE PARAMETERS
 		dw Invalid		; 0Ah
@@ -157,11 +333,24 @@ Int13FuncsEnd	equ $
 Int13FuncsMax	equ (Int13FuncsEnd-Int13Funcs) >> 1
 
 DriveNo		db 0			; Our drive number
+DriveType	db 0			; Our drive type (floppies)
 LastStatus	db 0			; Last return status
 
+		alignb 4, db 0
+Cylinders	dw 0			; Cylinder count
+Heads		dw 0			; Head count
+Sectors		dd 0			; Sector count (zero-extended)
+DiskSize	dd 0			; Size of disk in blocks
+DiskBuf		dd 0			; Linear address of high memory disk
+
+E820Table	dd 0			; E820 table in high memory
+Mem1MB		dd 0			; 1MB-16MB memory amount (1K)
+Mem16MB		dd 0			; 16MB-4G memory amount (64K)
+MemInt1588	dw 0			; 1MB-65MB memory amount (1K)
+
 		section .bss
 OldInt13	resd 1			; INT 13h in chain
+OldInt15	resd 1			; INT 15h in chain
 Stack		resd 1			; Saved SS:SP on invocation
+E820Buf		resd 6			; E820 fetch buffer
 SavedAX		resw 1			; AX saved during initialization
-
-
diff --git a/memdisk/memdisk.asm b/memdisk/memdisk.asm
index aa95f9ec..a690e66b 100644
--- a/memdisk/memdisk.asm
+++ b/memdisk/memdisk.asm
@@ -19,10 +19,15 @@
 
 		org 0h
 
+%define SECTORSIZE_LG2	9		; log2(sector size)
+%define	SECTORSIZE	(1 << SECTORSIZE_LG2)
+
 MyStack		equ 1024
 
 		; Parameter registers definition; this is the definition
 		; of the stack frame.
+%define		P_DS		word [bp+34]
+%define		P_ES		word [bp+32]
 %define		P_EAX		dword [bp+28]
 %define		P_AX		word [bp+28]
 %define		P_AL		byte [bp+28]
@@ -86,6 +91,7 @@ Done:		; Standard routine for return
 		mov [LastStatus],ah
 		mov P_AX,ax
 		cmp ah,1
+DoneWeird:
 		setnb al		; AL <- (AH > 0) ? 1 : 0 (CF)
 		lds bx,[Stack]		; DS:BX <- Old stack pointer
 		mov [bx+4],al		; Low byte of old FLAGS -> arithmetric flags
@@ -106,38 +112,208 @@ Reset:
 		and dl,80h		; Clear all but the type bit
 		jmp far [OldInt13]
 
+Invalid:
+		mov ax,0100h		; Unsupported function
+		ret
+
+GetDriveType:
+		pop ax			; Drop return address
+		mov ah,[DriveNo]
+		shr ah,7
+		or ah,02h		; CF = 0
+		mov P_AH,ah
+		mov [LastStatus],byte 0	; Success, but AH returns a value
+		jmp short DoneWeird
+
 GetStatus:
 		mov ah,[LastStatus]	; Copy last status
 		ret
 
-CheckIfReady:
+CheckIfReady:				; These are always-successful noop functions
 Recalibrate:
-		xor ah,ah		; Always successful
+InitWithParms:
+DetectChange:
+success:
+		xor ax,ax		; Always successful
 		ret
 
 Read:
+		call setup_regs
+do_copy:
+		call bcopy
+		movzx ax,P_AL		; AH = 0, AL = transfer count
+		ret
+
 Write:
+		call setup_regs
+		xchg esi,edi
+		jmp short do_copy
+
+		; These verify one sector only
+Seek:
+		mov P_AL,1
+
+		; Verify integrity; just bounds-check
 Verify:
-Format:
+		call setup_regs		; Returns error if appropriate
+		jmp short success	
+
 GetParms:
-InitWithParms:
-Seek:
-GetDriveType:
-DetectChange:
+		; We need to get the "number of drives" from the BIOS
+		mov dl,P_DL
+		inc dl			; The drive whose number we're stealing
+		mov ah,08h
+		int 13h
+		inc dl			; Add ourselves to the count
+		mov P_DL,dl		; Drive count
+		mov P_DI,di		; Steal the diskette parameter table if applicable
+		mov ax,es
+		mov P_ES,ax
+		mov bl,[DriveType]
+		mov P_BL,bl
+		mov ax,[Cylinders]
+		dec ax			; We report the highest #, not the count
+		or ah,[Sectors]
+		xchg al,ah
+		mov P_CX,ax
+		mov al,[Heads]
+		dec al
+		mov P_DH,al
+		xor ax,ax
+		ret
 
-Invalid:
-		mov ah,01h		; Unsupported function
+		; Convert a CHS address in CX/DH into an LBA in EAX
+chstolba:
+		xor ebx,ebx
+		mov bl,cl		; Sector number
+		and bl,3Fh
+		dec bx
+		mov si,dx
+		mov ax,[Heads]
+		shr cl,6
+		xchg cl,ch		; Now CX <- cylinder number
+		mul cx			; DX:AX <- AX*CX
+		shr si,8		; SI <- head number
+		add ax,si
+		adc dx,byte 0
+		shl edx,16
+		or eax,edx
+		mul dword [Sectors]
+		add eax,ebx
+		ret
+
+bcopy:
+		; Do something here
+
+		; Set up registers as for a "Read", and compares against disk size
+setup_regs:
+		call chstolba
+		movzx edi,P_BX		; Get linear address of target buffer
+		movzx ecx,P_ES
+		shr ecx,4
+		add edi,ecx
+		movzx ecx,P_AL
+		lea ebx,[eax+ecx]
+		mov esi,eax
+		shr esi,SECTORSIZE_LG2
+		add esi,[DiskBuf]
+		cmp ebx,[DiskSize]
+		jae .overrun
 		ret
 
+.overrun:	pop ax			; Drop return address
+		mov ax,0400h		; Sector not found
+		ret
+
+int15_e820:
+		cmp edx,534D4150h
+		jne near oldint15
+		cmp ecx,20		; Need 20 bytes
+		jb err86
+		push edx		; "SMAP"
+		push esi
+		push edi
+		and ebx,ebx
+		jne .renew
+		mov ebx,[E820Table]
+.renew:		mov esi,ebx
+		xor edi,edi
+		mov di,cs
+		shr di,4
+		add edi,E820Buf
+		mov ecx,24/4
+		call bcopy
+		add ebx, byte 12
+		pop edi
+		pop esi
+		mov eax,[cs:E820Buf]
+		mov [es:di],eax
+		mov eax,[cs:E820Buf+4]
+		mov [es:di+4],eax
+		mov eax,[cs:E820Buf+12]
+		mov [es:di+8],eax
+		mov eax,[cs:E820Buf+16]
+		mov [es:di+12],eax
+		mov eax,[cs:E820Buf+8]
+		mov [es:di+16],eax
+		cmp dword [cs:E820Buf+20], byte -1
+		jne .notdone
+		xor ebx,ebx		; Done with table
+.notdone:
+		pop eax			; "SMAP"
+		mov ecx,20		; Bytes loaded
+int15_success:
+		mov byte [bp+12], 02h	; Clear CF
+		pop bp
+		iret
+
+err86:
+		mov byte [bp+12], 03h	; Set CF
+		mov ah,86h
+		pop bp
+		iret
+
+Int15Start:
+		push bp
+		mov bp,sp
+		cmp ax,0E820h
+		je near int15_e820
+		cmp ax,0E801h
+		je int15_e801
+		cmp ax,0E881h
+		je int15_e881
+		cmp ah,88h
+		je int15_88
+oldint15:	pop bp
+		jmp far [OldInt15]
+		
+int15_e801:
+		mov ax,[cs:Mem1MB]
+		mov cx,ax
+		mov bx,[cs:Mem16MB]
+		mov dx,ax
+		jmp short int15_success
+
+int15_e881:
+		mov eax,[cs:Mem1MB]
+		mov ecx,eax
+		mov ebx,[cs:Mem16MB]
+		mov edx,eax
+		jmp short int15_success
+
+int15_88:
+		mov ax,[cs:MemInt1588]
+		jmp short int15_success
+
 		section .data
 Int13Funcs	dw Reset		; 00h - RESET
 		dw GetStatus		; 01h - GET STATUS
 		dw Read			; 02h - READ
 		dw Write		; 03h - WRITE
 		dw Verify		; 04h - VERIFY
-		dw Format		; 05h - FORMAT TRACK
-		dw Format		; 06h - FORMAT TRACK AND SET BAD FLAGS
-		dw Format		; 07h - FORMAT DRIVE AT TRACK
+		dw Invalid		; 05h - FORMAT TRACK
+		dw Invalid		; 06h - FORMAT TRACK AND SET BAD FLAGS
+		dw Invalid		; 07h - FORMAT DRIVE AT TRACK
 		dw GetParms		; 08h - GET PARAMETERS
 		dw InitWithParms	; 09h - INITIALIZE CONTROLLER WITH DRIVE PARAMETERS
 		dw Invalid		; 0Ah
@@ -157,11 +333,24 @@ Int13FuncsEnd	equ $
 Int13FuncsMax	equ (Int13FuncsEnd-Int13Funcs) >> 1
 
 DriveNo		db 0			; Our drive number
+DriveType	db 0			; Our drive type (floppies)
 LastStatus	db 0			; Last return status
 
+		alignb 4, db 0
+Cylinders	dw 0			; Cylinder count
+Heads		dw 0			; Head count
+Sectors		dd 0			; Sector count (zero-extended)
+DiskSize	dd 0			; Size of disk in blocks
+DiskBuf		dd 0			; Linear address of high memory disk
+
+E820Table	dd 0			; E820 table in high memory
+Mem1MB		dd 0			; 1MB-16MB memory amount (1K)
+Mem16MB		dd 0			; 16MB-4G memory amount (64K)
+MemInt1588	dw 0			; 1MB-65MB memory amount (1K)
+
 		section .bss
 OldInt13	resd 1			; INT 13h in chain
+OldInt15	resd 1			; INT 15h in chain
 Stack		resd 1			; Saved SS:SP on invocation
+E820Buf		resd 6			; E820 fetch buffer
 SavedAX		resw 1			; AX saved during initialization
-
-
diff --git a/pxelinux.asm b/pxelinux.asm
index 48696e37..f1d6158f 100644
--- a/pxelinux.asm
+++ b/pxelinux.asm
@@ -657,6 +657,17 @@ query_bootp:
 		call crlf			; ***
 
 ;
+; Check to see if we got any PXELINUX-specific DHCP options; in particular,
+; if we didn't get the magic enable, do not recognize any other options.
+;
+check_dhcp_magic:
+		test byte [DHCPMagic], 1	; If we didn't get the magic enable...
+		jnz .got_magic
+		mov byte [DHCPMagic], 0		; If not, kill all other options
+.got_magic:
+	
+
+;
 ; Initialize UDP stack
 ;
 udp_init:
@@ -779,16 +790,6 @@ mkkeymap:	stosb
 
 
 ;
-; Check to see if we got any PXELINUX-specific DHCP options
-;
-check_dhcp_magic:
-		test byte [DHCPMagic], 1	; If we didn't get the magic enable...
-		jnz .got_magic
-		mov byte [DHCPMagic], 0		; If not, kill all other options
-.got_magic:
-	
-
-;
 ; Store standard filename prefix
 ;
 prefix:		test byte [DHCPMagic], 04h	; Did we get a path prefix option
@@ -857,6 +858,7 @@ config_scan:
 		jz .no_option
 
 		; We got a DHCP option, try it first
+		push di
 		mov si,trying_msg
 		call writestr
 		mov di,ConfigName
@@ -864,6 +866,7 @@ config_scan:
 		call writestr
 		call crlf
 		call open
+		pop di
 		jnz .success
 
 .no_option:		; Have to guess config file name
@@ -3054,7 +3057,7 @@ use_font:
 		jne .text
 
 .graphics:
-		xor cx,bx
+		xor cx,cx
 		mov cl,bh			; CX = bytes/character
 		mov ax,480
 		div cl				; Compute char rows per screen
@@ -3063,7 +3066,7 @@ use_font:
 		mov [VidRows],al
 		mov ax,1121h			; Set user character table
 		int 10h
-		mov [VidRows], byte 79		; Always 80 bytes/line
+		mov [VidCols], byte 79		; Always 80 bytes/line
 		mov [TextPage], byte 0		; Always page 0
 		ret	; No need to call adjust_screen
 
@@ -4247,32 +4250,31 @@ parse_dhcp_options:
 		mov edx,[si]
 		mov [Netmask],edx
 		jmp short .opt_done
-
 .not_subnet:
+
 		cmp dl,3	; ROUTER option
 		jne .not_router
 		mov edx,[si]
 		mov [Gateway],edx
 		jmp short .opt_done
-
 .not_router:
+
 		cmp dl,52	; OPTION OVERLOAD option
 		jne .not_overload
 		mov dl,[si]
 		mov [OverLoad],dl
 		jmp short .opt_done
-
 .not_overload:
+
 		cmp dl,67	; BOOTFILE NAME option
 		jne .not_bootfile
 		mov di,BootFile
 		jmp short .copyoption
-
 .done:
 		ret		; This is here to make short jumps easier
-
 .not_bootfile:
-		cmp dl,176	; PXELINUX MAGIC option
+
+		cmp dl,208	; PXELINUX MAGIC option
 		jne .not_pl_magic
 		cmp al,4	; Must have length == 4
 		jne .opt_done
@@ -4280,23 +4282,23 @@ parse_dhcp_options:
 		jne .opt_done
 		or byte [DHCPMagic], byte 1		; Found magic #
 		jmp short .opt_done
-
 .not_pl_magic:
-		cmp dl,177	; PXELINUX CONFIGFILE option
+
+		cmp dl,209	; PXELINUX CONFIGFILE option
 		jne .not_pl_config
 		mov di,ConfigName
 		or byte [DHCPMagic], byte 2	; Got config file
 		jmp short .copyoption
-
 .not_pl_config:
-		cmp dl,178	; PXELINUX PATHPREFIX option
+
+		cmp dl,210	; PXELINUX PATHPREFIX option
 		jne .not_pl_prefix
 		mov di,PathPrefix
 		or byte [DHCPMagic], byte 4	; Got path prefix
 		jmp short .copyoption
-	
 .not_pl_prefix:
-		cmp dl,179	; PXELINUX REBOOTTIME option
+
+		cmp dl,211	; PXELINUX REBOOTTIME option
 		jne .not_pl_timeout
 		cmp al,4
 		jne .opt_done
@@ -4307,8 +4309,8 @@ parse_dhcp_options:
 		mov [RebootTime],edx
 		or byte [DHCPMagic], byte 8	; Got RebootTime
 		; jmp short .opt_done
+.not_pl_timeout:
 
-.not_pl_timeout
 		; Unknown option.  Skip to the next one.
 .opt_done:
 		add si,ax
@@ -4584,11 +4586,13 @@ vgasetmode:
 		mov ax,1A00h		; Get video card and monitor
 		xor bx,bx
 		int 10h
-		cmp bl, 8		; If not VGA card/VGA monitor, give up
-		jne .error		; ZF=0
+		sub bl, 7		; BL=07h and BL=08h OK
+		cmp bl, 1
+		ja .error		; ZF=0
 ;		mov bx,TextColorReg
 ;		mov dx,1009h		; Read color registers
 ;		int 10h
+.ok:
 		mov ax,0012h		; Set mode = 640x480 VGA 16 colors
 		int 10h
 		mov dx,linear_color
@@ -4611,20 +4615,21 @@ vgaclearmode:
 		push ds
 		push cs
 		pop ds			; DS <- CS
-		pushad
 		cmp [UsingVGA], byte 1
 		jne .done
+		pushad
 		mov ax,0003h		; Return to normal video mode
 		int 10h
 ;		mov dx,TextColorReg	; Restore color registers
 ;		mov ax,1002h
 ;		int 10h
-
+		mov [UsingVGA], byte 0
 
 		call use_font		; Restore text font/data
 		mov byte [ScrollAttribute], 07h
-.done:
 		popad
+.done:
+
 		pop ds
 		ret
 
diff --git a/pxelinux.doc b/pxelinux.doc
index 96e95cbf..2ec710c1 100644
--- a/pxelinux.doc
+++ b/pxelinux.doc
@@ -235,20 +235,20 @@ PXELINUX (starting with version 1.62) supports the following
 nonstandard DHCP options, which depending on your DHCP server you may
 be able to use to customize the specific behaviour of PXELINUX:
 
-Option 176	pxelinux.magic
+Option 208	pxelinux.magic
 	- Must be set to F1:00:74:7E (241.0.116.126) for PXELINUX to
 	  recognize any special DHCP options whatsoever.
 
-Option 177	pxelinux.configfile
+Option 209	pxelinux.configfile
 	- Specifies the PXELINUX configuration file name.
 
-Option 178	pxelinux.pathprefix
+Option 210	pxelinux.pathprefix
 	- Specifies the PXELINUX common path prefix, instead of
 	  deriving it from the boot file name.  This almost certainly
 	  needs to end in whatever character the TFTP server OS uses
 	  as a pathname separator, e.g. slash (/) for Unix.
 
-Option 179	pxelinux.reboottime
+Option 211	pxelinux.reboottime
 	- Specifies, in seconds, the time to wait before reboot in the
 	  event of TFTP failure.  0 means wait "forever" (in reality,
 	  it waits approximately 136 years.)
@@ -258,10 +258,10 @@ options; you can use the following syntax in dhcpd.conf if you are
 running this version of dhcpd:
 
 	option space pxelinux;
-	option pxelinux.magic      code 176 = string;
-	option pxelinux.configfile code 177 = text;
-	option pxelinux.pathprefix code 178 = text;
-	option pxelinux.reboottime code 179 = unsigned integer 32;
+	option pxelinux.magic      code 208 = string;
+	option pxelinux.configfile code 209 = text;
+	option pxelinux.pathprefix code 210 = text;
+	option pxelinux.reboottime code 211 = unsigned integer 32;
 
 Then, inside your PXELINUX-booting group or class (whereever you have
 the PXELINUX-related options, such as the filename option), you can
@@ -272,12 +272,25 @@ add, for example:
 	option pxelinux.configfile "configs/common";
 	option pxelinux.pathprefix "/tftpboot/pxelinux/files/";
 	option pxelinux.reboottime 30;
+	option dhcp-parameter-request-list 1, 3, 208, 209, 210, 211;
 	filename "/tftpboot/pxelinux/pxelinux.bin";
 
 Note that the configfile is relative to the pathprefix: this will look
 for a config file called /tftpboot/pxelinux/files/configs/common on
 the TFTP server.
 
+The "option dhcp-parameter-request-list" is unfortunately required,
+since the DHCP exchange happens before PXELINUX starts.
+Unfortunately at least DHCP 3.0rc2pl1 takes this as "send these
+options and no others", even when the client explicitly requests
+them.  This can easily cause problems for your operating system; you
+may need to add additional options here.  I'm afraid I don't have a
+neat and clean solution for this problem using existing software.
+Fixing it in PXELINUX would require a fairly large amount of
+additional code, since PXELINUX would be required to conduct its own
+DHCP exchange rather than getting the cached packet from the PXE
+stack.
+
 Using ISC dhcp 3.0 you can create a lot of these strings on the fly.
 For example, to use the hexadecimal form of the hardware address as
 the configuration file name, you could do something like: