[Linphone-users] SNDRV_PCM_IOCTL_PREPARE/snd_pcm_writei problem in linphonec

[Greg Farrell]

Hi,

  I'm controlling linphonec progmatically from a gui front end. The 
fgets() in
the main loop is replaced with a select()/read on a fifo.

If I make phone calls out everything works perfectly. If I answer a call 
then
linphone is unable to access the local capture device as far as I can 
tell. So
0 packets are listed as sent via rtp, and there are about 10 spams of

(process:2255): MediaStreamer-WARNING **: alsa_card_write: 
snd_pcm_writei() failed:Resource temporarily unavailable.
ALSA lib pcm_hw.c:466:(snd_pcm_hw_prepare) SNDRV_PCM_IOCTL_PREPARE 
failed: Device or resource busy

I've added logging to alsa_card_open/close_[rw] and it all looks pretty 
sensible. There are no double opens, or any
opens without a close that I can see. Can anyone give me any suggestions 
why these attempts to access the pcm are
failing?

Using lsof only linphonec has any alsa devices open. Also the same 
devices are open during a succesful call (one initiated by
linphone) versus an unsucessful call (one answered by linphone).

linphonec 4283 root  mem    CHR 116,16      4587595 pcmC0D0p
linphonec 4283 root  mem    CHR 116,24      4587594 pcmC0D0c
linphonec 4283 root    3u   CHR  116,0      4587542 controlC0
linphonec 4283 root   14u   CHR 116,24      4587594 pcmC0D0c
linphonec 4283 root   15u   CHR 116,16      4587595 pcmC0D0p

The call is connected but no data is recorded or sent by linphone. The 
other end hence hears silence.

Are I wrong in thinking that this is a PCM device locking issue? Any 
suggestions on what to try? Everything looks identical
from the debug lvl 6 logs in a succesful run as in an unsucessful. Right 
up unto the point where it fails to write to the PCM.

I've uploaded some debug logs, including some hopefully self-explanatory 
printfs() of my own at:
http://pastebin.com/713614

thanks a lot,
    Greg