[mythtv-users] Alsa Prealloc Query

Zooka mythtv at fitzy.org
Tue Dec 14 21:04:51 UTC 2010


I was going through my frontend log on my 0.24-65-g1405782 build and 
came across this.

2010-12-15 06:25:50.649 ALSA, Error: Error opening 
/proc/asound/card0/pcm0p/sub0/prealloc: Permission denied. Try to 
increase it with: echo 37 | sudo tee /proc/asound/card0/pcm0p/sub0/prealloc
2010-12-15 06:25:50.649 ALSA, Error: Unable to sufficiently increase 
preallocated buffer size - underruns are likely

Via commandline I checked that prealloc was set to 64, higher than 37. 
I thought it strange that myth would try to set a buffer lower when it 
looked like it was trying to make it higher.., but changed it to 37 
anyways (using the exact same command issued in the report, which 
worked).  Restarting a recording that same ALSA error occured.  I then 
changed the prealloc to 128 and the error disappeared.

What is going on?  Why would myth try to change it lower, when it 
actually needed to be higher?


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