[mythtv-users] prebuffering pause related to agpgart?

Darren Richards darren.richards at gmail.com
Wed Jan 19 21:05:55 EST 2005


On Wed, 19 Jan 2005 08:26:58 +0100, Thomas Börkel <thomas at boerkel.de> wrote:
> HI!
> 
> Darren Richards wrote:
> 
> > I've had my mythtv setup running solidy for nearly a year now with
> > FC1.  I decided to upgrade my hard drive and the OS at the same time.
> > I've installed FC3 with the 2.6.10-1.741_FC3 kernel.  I used apt-get
> > and Jarod's guide.
> >
> > With FC1, watching live TV or a recording would take about 30% ov my
> > cpu.  Now mythfrontend and X together are taking 95-100% of my CPU.
> > I've searched the archives and I suspect the problem may be related to
> > agpgart.  I have an nvidia graphics card and I want to use NvAGP, but
> > even though I set "NvAGP" "1" in xorg.conf, agpgart is still getting
> > loaded.
> >
> > /proc/driver/nvidia/agp says:
> >
> > AGP initialization failed, please check the output
> > of the 'dmesg' command and/or your system log file
> > for additional information on this problem.
> >
> > dmesg contains the following lines:
> >
> > NVRM: not using NVAGP, AGPGART is loaded!!
> > NVRM: not using NVAGP, AGPGART is loaded!!
> >
> > I've tried adding agpgart to /etc/hotplug/blacklist, but it still gets loaded.
> 
> If you look at /proc/driver/nvidia/agp/status you'll notice, that AGP is
> disabled in your case (AGPGART loaded and NvAGP=1), resulting in very
> high CPU usage of X.
> 
> I have had the same problem with 2.6.9 and FC2 (Celeron 1.3 GHz). I have
> come to the conclusion, that you cannot use NVidia's AGP driver, if
> AGPGART is compiled into the kernel (I have tried several kernel boot
> parameters to get rid of AGPGART unsuccessfully).
> 
> So, I have set NvAGP=3 in xorg.conf and so AGPGART is being used (again
> check /proc/driver/nvidia/agp/status).
> 
> X is still using CPU, but much less (13%). I don't know, if it would use
> only 1% CPU with NVidia-AGP, as it does on another machine with
> FC1/Kernel 2.4/NvAGP=1 or if the higher X usage is coming from
> FC2/Kernel 2.6. At least the prebuffering pauses are gone with AGPGART.
> 
> Please let me know, what your CPU usage of X is with NvAGP=3.
> 
> Thomas

NvAGP=3 didn't seem to help much.  I think I'm seeing fewer
prebuffering pauses, but X is still taking about 40% and mythfrontend
is taking about 55%.  If I enable kernel deinterlacing (which I used
with FC1), I still get a prebuffering pause every 2-3 seconds.

It looks like my only solution is to compile the kernel without
agpgart, unless there's an rpm package out there somewhere.  I've
never compiled a kernel before...

-darren


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