Improving rotated ATI performance

[Jerome Glisse]

On Fri, 14 Dec 2007 09:58:39 -0600
"Adr3nal D0S" <adr3nald0s at gmail.com> wrote:

> On Dec 14, 2007 9:45 AM, Alex Deucher <alexdeucher at gmail.com> wrote:
> > On Dec 14, 2007 9:25 AM, Jerome Glisse <glisse at freedesktop.org> wrote:
> > >
> > > Alex would be good if you can double check but r300 hw i got can't
> > > properly render 3d above 2650x2650 (offset things you can see in the
> > > drm). As side note fglrx doesn't render properly above this limit.
> > > So i think we should change advertized viewport size to 2650, i
> > > will do that soon if no one object with valid arguments.
> >
> > you are right the r3xx r4xx car limited to 2560.  I forgot about that.
> >  Go ahead and fix that up.
> 
> I don't completely understand this part of the discussion. But, will
> it prevent me from having a Virtual of 3520 1920 with GLX loaded.
> Granted it seems to be falling back to software-based GL, but that's
> fine for my usage.

Well it will prevent you to render to any viewport bigger than 2560
ie you won't be able to have glx app with screen size bigger than 2560
in either x or y direction. So for instance no compiz at such resolution.

There is two work around for this:
- in the application split rendering into several tile which followh
  the 2560 constraint.
- hack the driver to split rendering into several tile this need that
  you resumit cmd as many times as there is tiles and adjust viewport
  to render to a given tile each time.

I think the second solution is painfull to implement with current
mesa infrastructure, it might be a lot easier in gallium with a proper
memory management.

Cheers,
Jerome Glisse