Re: Windows multi-VGA support

["John R Pierce" <pierce@hogranch.com>]

>  Where can I get the information about hardware modification?


'modification' is probably the wrong word.  The VGA hardware must meet
certain requirements, all of which are spelled out in the PC'97 spec from
MSFT.  Basically, the static VGA registers and A000:0000-B000:FFFF memory
map must be totally disabled.  The windows graphics drivers must be able to
operate entirely with relocatable PCI resources, including the cursor and
ramdac (i.e. not have to use ANY vga port or memory accesses).  There are
some additional issues with the VGA bios on secondary cards.

>  Will the modification be reflected in the PCI specification?

No, I doubt it.

>  Which VGA devices are/will be ready for multi-VGA?

ATI, S3 Virge, many others.

>  Is updating VGA driver necessary to use multi-VGA even if a
>  modified device has backword compatibility?

Yes.  The 'driver' itself doesn't need changes, I don't think, but the
miniVDD does.

>  Will an AGP device and PCI devices work together?


Yes, but the current situation is a bit less than desirable.  The default
behavior of a 'standard' BIOS faced with both is to leave the AGP card
disabled and initialize the PCI card.  Then Win98 comes along and uses the
PCI card as the primary and sets up the AGP as the secondary.  I dunno about
you, but I'd prefer the primary be the fastest, which is undoubtably the
AGP.

All of this along with all the technical details is spelled out in a few
small doc files on the Win98 beta CDroms.  The display driver specifics will
undoubtably be different for NT5.0.

-jrp