patch

[valette at crf.canon.fr (VALETTE Eric)]

>>>>> "joel" == joel  <joel at OARcorp.com> writes:

joel> On Mon, 7 Sep 1998, VALETTE Eric wrote:

>> >>>>> "joel" == joel  <joel at OARcorp.com> writes:
>> 
joel> On Tue, 1 Sep 1998, Quality Quorum wrote:
>> 
joel> Doesn't the CMOS RAM on a standard PC have a way to determine if a video
joel> card is present?
>> 
>> Probably. Note that standart BIOS just stop if they do not find the
>> video card so it may be hard to test...

joel> What is done in more embedded PC's to avoid this?  In a normal PC, you
joel> would always have a video card.  In an embedded PC, this must be handled.  
joel> I assume the BIOS in the embedded PC is a bit more lenient in this regard
joel> and continues.  Still there has to be a way for this to be represented in
joel> the CMOS which is at worst an extension to the standard settings.

Additionnal info. May be testing the first bit is enough at 0x409 is enough :)


40:89	byte	Video display data area (MCGA and VGA)

		?7?6?5?4?3?2?1?0? Video display data area (MCGA and VGA)
		 ? ? ? ? ? ? ? ??? 1=VGA is active
		 ? ? ? ? ? ? ???? 1=gray scale is enabled
		 ? ? ? ? ? ????? 1=using monochrome monitor
		 ? ? ? ? ?????? 1=default palette loading is disabled
		 ? ? ? ??????? see table below
		 ? ? ???????? reserved
		 ? ?????????  1=display switching enabled
		 ?????????? alphanumeric scan lines (see table below)

%		Bit7   Bit4	Scan Line information
		 0	0	350 line mode
		 0	1	400 line mode
		 1	0	200 line mode
		 1	1	reserved

	40:8A	byte	Display Combination Code (DCC) table index (EGA+)