On Thu, 26 Oct 2000, Jeffrey B. Siegal wrote:
> I think an easier way to get X work would be with flat 256 color (one byte per
> pixel). Then there are no latches to worry about. There is a standard VGA mode
> for 320x200, and VESA linear-address modes for higher resolution. (This would
> work with vesafb and XF86_FBdev.)
>
I agree with that, too. If running in full-screen mode, no latch access
even has to be trapped for 16 color modes, because VGA has been designed
to allow to completely save/restore state of video in hardware (dump of
vram, and regs are r/w). I remember that used to be one of the major
advantages of VGA over very similar older EGA standard, which was less
multitasking OS'es friendly because it didn't allow to get full state of
video hardware. Interestingly, is it possible to get a quick fast hack of
running plex86 with modern 3d accelerators in full-screen mode not having
to write special drivers/layer of access to host OS drivers, just by
saving full video state, re-initing card (in a similar way that BIOS is
doing) and allowing direct access to video in full-screen mode, when you
switch to host OS/other apps, it will restore the prevoiusely saved state.
My point was, I believe that windows doesn't trap that much of video when
it runs VGA full-screen (I might be wrong, but it looks fast). You
have to write initer/saver/restorer of state for this specific
card, which should be easier than writing the complete driver. Running in
window would be more tricky, of course (it's just I personally feel enough
to run full-screen).
Uhus
