Continued from here:
http://article.gmane.org/gmane.linux.alsa.devel/121575
http://www.alsa-project.org/main/index.php/XRUN_Debug
# Enable basic debugging and dump stack, check hardware pointer on the period update # Usefull to just see, if PCM stream is stopped for a reason (usually
wrong
audio process timing from scheduler) # And to check the values from driver
echo 11 > /proc/asound/card0/pcm0p/xrun_debug
Okay, I not compiled my own kernel with CONFIG_SND_PCM_XRUN_DEBUG, CONFIG_SND_VERBOSE_PROCFS, CONFIG_SND_DEBUG all enabled in the kernel configuration, I have an xrun_debug file, but it doesn't seem to list anything, then I also tried with cat instead of echo, and just a 0 showed
up:
$ echo 11 > /proc/asound/card0/pcm0p/xrun_debug bash: /proc/asound/card0/pcm0p/xrun_debug: Permission denied
# echo 11 > /proc/asound/card0/pcm0p/xrun_debug bash: /proc/asound/card0/pcm0p/xrun_debug: Permission denied
$ cat /proc/asound/card0/pcm0p/xrun_debug 0
You need root privilege to debug
sudo echo 11 > /proc/asound/card0/pcm0p/xrun_debug
Check the system log , you should find the hwptr change at 10ms interval if vlc use period time of 10ms
Try different period time/size to verify that the hardware really support any arbitrary period time/size requested by the application ?