X performance problems with Matrox G550

[Michel Dänzer]

On Tue, 2004-11-02 at 23:18 +0000, Martin Ebourne wrote:
> 
> I have an Athlon 64 with a Matrox G550 running mythTV (a TV pvr
> program). I am running myth on the second head (CRTC2) using the TV out.
> In this configuration myth is doing software decoding of an MPEG2
> stream, scaling it to the TV resolution, performing YUV to RGB32
> colourspace mapping; X is simply copying the image to the videocard by
> use of the XShmPutImage call.

There's no XVideo support for the colourspace conversion and scaling?


> 	*dst++ = FbDoDestInvarientMergeRop(*src++);  // THIS IS THE SLOW LINE

Is write-combining enabled for the framebuffer?


> So now is the point where I'm getting a bit stuck. Can anyone explain
> why these accesses are so slow? It's an AGP x4 card, and the Xorg log
> reports it as such (the agp option is in the xorg.conf).

Is direct rendering enabled? AGP doesn't come into play otherwise.


PS: We could have determined most if not all of this from your X server
log.

-- 
Earthling Michel Dänzer      |     Debian (powerpc), X and DRI developer
Libre software enthusiast    |   http://svcs.affero.net/rm.php?r=daenzer