[mythtv-users] Prebuffering pause problem - my conclusions - 2.6 kernel

Kyle Kelly kyle at kylekelly.com
Fri Oct 22 18:37:44 UTC 2004

Buechler, Mark R wrote:

>A few days ago I put together some spare hardware (PII @ 500/100mhz, 320megs
>RAM) for another MythTV frontend. I decided to install SuSE 9.1 with the new
>2.6 kernel. I'm using a CVS version from 9/10 compiled for SuSE 8.2. When
>watching live TV I get every 2-4 seconds "prebuffering pause". When I watch
>a recording it's a bit less often but still quite noticeable. I read several
>posts concerning this problem and do a bit of debugging and basically get
>nowhere. The steps I followed:
>1. Re-compile MythTV for SuSE 9.1 using a new CVS version - no difference.
>2. Re-compile QT for SuSE 9.1 - no difference.
>3. Re-nice X and mythfrontend to -15 - no difference
>4. Move cards around making sure no cards are sharing IRQs - no difference.
>5. Replace overclocked PII with a PII 400 and run it at 400 - no difference.
>6. Swap memory making sure memory is true PC100 - no difference.
>7. Remove soundcard thinking Myth could be waiting on audio IO - no
>At this point the only thing I could think to try and getting rid of the 2.6
>kernel in favor of a 2.4 kernel I have on all the rest of my Myth boxes. I
>did a fresh install of SuSE 8.2 and started up Myth in live TV. Bingo! No
>prebuffering pause!
>Has anyone else encountered issues with Myth under 2.6? Could it be
>something particular with SuSE 9.1?
>- Mark.
I was using a 2.6.5 kernel with no problems, but just yesterday I 
upgraded to a 2.6.8 kernel and now I'm getting the prebuffering pauses, 
I can fix it if nothing else is running on the box and renice 
mythfrontend to -19, thankfully I don't watch livetv often.  I'm 
thinking it could be as simple as one single option I enabled in this 
new kernel version that is causing the problem.  I did a diff on my 
.config's for the two versions and could not notice anything that could 
have caused the problem, although I don't really know what I'm looking 
for.  It could also be my version of ivtv, I tried a few different 
versions yesterday, a couple from 0.2 and a few from 0.1 (one even 
caused a Kernel Panic) and ended up sticking with 
ivtv-0.1.10-pre2-ck104f, but now my dmesg is getting a lot of  "ivtv: 
VIM Restart" messages...

I guess I'll just keep trying new kernels and ivtv versions until I come 
up with a good combo.

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