[mythtv-users] prebuffering pause related to agpgart?

[Thomas Börkel]

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