Re: [Dri-devel] Radeon/r200 texture engine question

[Michel <mi...@da...>]

On Sat, 2003-09-27 at 23:10, Alex Deucher wrote:
> --- Michel Dnzer <mi...@da...> wrote:
> > On Fri, 2003-09-26 at 18:16, Alex Deucher wrote:
> > > 
> > > When implemeting this on radeon, would I have to use the CP
> > > to program the texture registers or could I use MMIO?  
> > 
> > Using the 3D engine without the CP is hard if not impossible.
> 
> how do 2D, 3D, CP, etc fit together.  I take it the CP is mainly a
> queue for 3D commands, but can also process register writes?  

It's basically a general command queue.

> I understand how the to issues commands for 2D to the CP, but how does 3D
> work?  

Similarly, via special 3D command packets.

> The DRI driver seems very foreign by comparison.  having looked
> it over it guess the various functions queue up 3D commands which are
> then flushed to the 3D engine at some point.  where do that commands
> get flushed?  

In the DRM.

> can I just use the texture commands or do I need to recreate the commands 
> to create a quad first and then the texture? 

The latter, there's no 'texture command' per se, textures are just part
of the hardware state.


> > > I've been toying with the idea of converting the existing Xv code
> > to CP 
> > > anyway, however if you disabled the DRI and wanted to use the
> > overlay or 
> > > the texture engine you'd need an MMIO code path at least.
> > 
> > The register write macros could be changed (or new ones added) to use
> > the CP transparently when appropriate.
> 
> do you mean like psuedo-MMIO using the CP?  or just other macros like
> the 2D accel code uses (OUTRING() and such).  

Either.

> is it possible to use the 3D engine at all when the DRI is not enabled?

AFAIK it's not possible to use the 3D engine without the CP. Apparently,
it's possible to use the CP with MMIO though, but I haven't seen code or
even documentation on how to do it.


> > As a bonus, once you've solved all the issues involved, adding some
> > RENDER extension acceleration should be trivial. :) I played with
> > that a
> > little but never found the time to get it very far.
> 
> Do you have any code (however broken) I could look at?

Sure, http://penguinppc.org/~daenzer/DRI/radeon_render.c . It's for the
R100 3D engine, and it doesn't render anything yet, or at least not
anything like what it's supposed to. :\


-- 
Earthling Michel Dänzer   \  Debian (powerpc), XFree86 and DRI developer
Software libre enthusiast  \     http://svcs.affero.net/rm.php?r=daenzer