From: roell@informatik.tu-muenchen.de (Thomas Roell) Subject: Re: XFree 1.1 with T8900; mixed results. Date: 28 Dec 1992 18:18:42 GMT
> 2. why does the 256 color Trident display driver only support
> T8900C chips? What's this annoying difference between the
> T8900B and C?
That's a very trivial reason. For some X stuff you need to have access
to a source byte and a destination byte at the same time. If you deal
with SVGA's which cannot map their whole 1MB video memory into the
CPU's address space, you have to do banking. If you also have to
fullfill the upper constraint, then you see that you need to have two
banks which can be used independantly (since source and destination of
the operation might not be in the same bank).
The TVGA8900B supports only ONE bank, while the TVGA8900C supports TWO
banks.
- Thomas