[mythtv-users] Fixed: HD playback stutter after resume

[Leighton Brough]

Some time ago I posted about a problem I had with HD playback stutter 
which only happened after resuming from suspend-to-ram. As I didn't get 
any replies, and I've now found an acceptable solution, I thought I 
should post the details for the benefit of others who may have HD 
playback problems.

Turning off AGP support for my NVidia 6200 seems to have totally fixed 
all playback issues for me (with a P4 3.0GHz processor). I did this by 
setting:

Option "NvAGP" "0"

in my xorg.conf.

I am using real-time threads, kernel deinterlacing and extra audio 
buffering in the frontend playback settings. I had also found, as have 
others who've posted to the list that turning off sync to vblank in 
nvidia-settings helps HD playback, but this had the side effect of 
causing tearing in the playback (which I found unacceptable once my eye 
was tuned to notice it). With AGP support off, I can turn the sync to 
vblank back on, which eliminates the tearing.

It seems in my case that the AGP state isn't restored correctly after 
resuming from suspend-to-ram. However I suspect that turning off AGP 
could help others with HD playback issues too. Precisely what this 
setting means in practice is a mystery to me: what bus is used by an AGP 
card when AGP support is disabled?
It seems there's no performance problem with this setting off, for me at 
least, but I really don't know much about AGP. Perhaps someone can 
enlighten me?

Leighton