Xvideo performance on Radeon 7500 vs Intel 915

Roland Scheidegger sroland at tungstengraphics.com
Thu Dec 14 11:57:24 PST 2006

Michel Dänzer wrote:
> On Thu, 2006-12-14 at 11:52 -0500, Ken Mandelberg wrote:
>> After the failure, the driver tries
>> xf86QueryLargestOffscreenLinear(pScreen, &max_size, 16,
>>                                              PRIORITY_EXTREME);
>> and max_size comes back 1,479,808 which is too small.
>> So I guess myth is using enough of the "OffscreenLinear" in the GUI to 
>> leave not enough left for the actual video.
>> I've turned off myth's preview mpg imaging, and its not apparent to me 
>> where the qt myth interface is using the resource. It doesn't show up in 
>> the alloc points I'm catching in radeon_video.c.
> The only offscreen memory usage that I know of that can't be overridden
> by the driver Xv code is for GLX renderbuffers and textures. Try
> reducing the amount reserved for textures with Option "FBTexPercent".
That'll only work with exa though, with xaa the amount reserved for
textures can only be increased.
I guess that means myth has a 3d frontend which will cause the driver to
reserve backbuffer, zbuffer and memory for textures. You could of course
use the usual workarounds for not enough memory, decrease resolution,
decrease color depth to 16bit, decrease z-buffer to 16bit, or even don't
allocate a back buffer... None of that is a really good solution though.


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