X performance on mini-itx boards

Lee Revell rlrevell at joe-job.com
Thu Sep 2 00:38:57 PDT 2004

On Thu, 2004-09-02 at 03:26, Francois Tigeot wrote:
> On Tue, Aug 31, 2004 at 09:43:16PM +0100, Hamie wrote:
> > What sort of performance on the VIA mini-itx boards can be expected with 
> > XOrg? Is there hardware acceleration available for these boards? WHat 
> > sort of fps can you get with glxgears at default size?
> I have found fanless VIA ME-6000 perfectly adequate for 2D work.

The current 2D driver has some recently identified problems, where
excessive 2D engine activity (dragging around the mplayer window) would
completely stall the PCI bus, with the symptoms that interrupt handlers
can be delayed for arbitrary lengths of time, leading to audio (and
probably other) problems.  These should be fixed soon.  This is what the
maintainer told me:

> I've think I've found an answer to this, and it seems to be related to
> what I mentioned earlier, namely that any attemt to write over PCI to a
> busy video engine will halt the processor until the video accepts new
> data.

> The wait-for-idle loop seems only to be used as a flush-and-sync, to make
> sure that accelerated rendering has completed. There is probably no check
> for ongoing engine activity before writing to the 2d engine. Same as for
> VIA's own mpeg2 code. Such a check will be implemented and will cause a
> very slight overhead compared to today's code.

> I'm starting to fix this as part of compatibility with the new drm with
> AGP DMA transfers, when available. This will not go into "production" for
> about least two or three weeks


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