EXA

[Michel Dänzer]

On Wed, 2007-08-08 at 14:36 +0200, Lukas Hejtmanek wrote: 
> On Wed, Aug 08, 2007 at 11:19:19AM +0200, Michel Dänzer wrote:
> 
> > >    Btw, is it possible to expose offscreen pixmap to the application so that
> > >    PutImage and GetImage can be safely ignored?
> > 
> > Not sure that's what you mean, but you can try commenting out the
> > exaDoMigration call in exaGetImage to see if that makes any difference.
> 
> Forget that question, [...]

Have you still tried my suggestion though? It's perfectly possible that
migrating the pixmap to system memory in exaGetImage is generally a bad
idea.


> But the point here is that EXA seems to spend huge amount of time to Put and
> Get images. XAA does only PutImage and it seems to be faster. I understand
> that with EXA, it is cost of acceleration because we need to keep pixmap in
> offscreen area to do acceleration and then to migrate to the system memory to
> use CPU for some raster operations. Am I right? While in the case of XAA, the 
> most operations is done by CPU and the result is only transfered to offscreen
> area.

Right.


> > As has been pointed out, it could be done using the IRQ. This will
> > probably happen via fences when using TTM, in the meantime you could try
> > using DRM_IOCTL_I915_IRQ_EMIT and DRM_IOCTL_I915_IRQ_WAIT.
> 
> Using this approach, IRQ should be generated after the accelerator has
> finished a request?

For starters, just emit an interrupt in I830Sync() and wait for it.


-- 
Earthling Michel Dänzer           |          http://tungstengraphics.com
Libre software enthusiast         |          Debian, X and DRI developer