[Open-graphics] Initial thoughts

[Andy Goth]

On Fri, Dec 03, 2004 at 02:33:07AM +0000, Rogelio Serrano wrote:
> > Unless the next version of MS-Windows will use 3D in its loading
> > screen, the flash only needs to store VGA emulation code.
> 
> Even if MS-Windows use 3D in the loading screen its still wrong to do
> that.

Yeah, it would be extra work to write separate VGA-only and full-3D
firmwares, but I was trying to make a general statement about what's
minimally required.  If we get caught in the unlikely situation of
needing to dump VGA emulation in order to have room for 3D, we can have
separate firmwares for boot loading and after the OS is active, then
switch when the driver loads.

> Going straight to framebuffer mode would be better.

Frame buffer mode may be easier to program, but boot loading is all
about being compatible with old (possibly very old) code, for instance
your system's boot loader.  Ironically, boot loaders are primarily
designed to be compatible with very old hardware.  Hence there's no
progress until the OS comes up and both the hardware and the software
can stop pretending it's 1980.

> Well its a BIOS issue anyway. Can we get rid of VGA emulation?

So long as there are important programs out there that insist on
directly accessing the graphics card and treating it like a CGA/EGA/VGA,
we will need this feature.  And the BIOS boot loader is pretty dang
important.

It's a shame we can't implement the VGA emulation entirely in software.
If all MS-DOS-ish programs accessed the graphics card through BIOS INT
0x10 and friends, then we'd be able to write a video BIOS driver that
translates all text and pixel-oriented graphics calls into the
equivalent 3D I/O.  But even this might be impossible since the driver
would have to run in real mode--- how would we mmap the hardware?

-- 
Andy Goth  +  unununium at openverse.com  +  http://ioioio.net/