Re: [Qemu-devel] Graphic card

["Jim C. Brown" <jma5@umd.edu>]

On Mon, Oct 31, 2005 at 09:58:45AM +0000, Ricardo Almeida wrote:
> On 10/30/05, Mike Swanson <mikeonthecomputer@gmail.com> wrote:
> >
> >
> > 3. Perhaps, but there's two things here. First of all, the card would
> > have to be documented in a fair amount of low-level detail, something
> > that big video card companies rarely or never do.
> 
> 
> What about the Via/S3 Unichrome? Via allows access to the Linux Video
> Interface (http://www.viaarena.com/default.aspx?PageID=151) and there are
> open source drivers (http://sourceforge.net/projects/unichrome/) from where,
> to my believe, it's possible to understand the graphic card.
> I'm just a java developer so I really can't help in any of the hard work.
> Just trying to make some suggestions to improve this great software :)
> 

It will still be fairly hard to do, even if its completely open.

Since Via S3/Unichrome is supported by DRI, I'd say that it looks doable
(at least on a first glance). Better than say a Nvidia or ATI card. Since
those aren't open, we can't implement them without careful reverse engineering
(even their open source drivers don't handle 3d).

> Secondly, the
> > complexity of the card might make its emulated implementation even
> > slower than the Cirrus one used currently
> 
> 
> This is something I tend to dissagree... People aren't going to emulate a
> full pc in a slow one. The worst graphic card sold today (picked a random
> online shop here in Portugal) is a GeForce FX5200, with DirectX 9.0 and
> OpenGL 1.4 hardware accelaration. I'm sure most calls to the emulated
> graphic card can have an almost direct call.
> Cirrus card can still be emulated, but I don't see nothing wrong in having
> an emulated card that requires a 60? graphic card to work...
> 

See above. It is only plausible if the card's specs are completely open with
respect to 3d acceleration.

Even then, "directly" rerouting calls only works if the host happens to have the
same hardware. And that would probably require exclusive use of the video card.

It may be possible to route the low level calls from the emulated card to a
higher level api on the host, such as OpenGL.

-- 
Infinite complexity begets infinite beauty.
Infinite precision begets infinite perfection.