Connecting to ALSA

Question

When I try to connect to the ALSA sound system as another user on one of our machines I get the following message- "ALSA lib pcm_dmix.c:975:(snd_pcm_dmix_open) unable to create IPC semaphore". The machine has been logged in as another user in our system. It doesn't matter if I use aplay or my application I get the same message. If I run as root the application connects to the ALSA system and plays the sound. If I su to the user who is logged into the console I get the same failure.

Does anyone have any ideas? I have tried to use setcap on my program but this failed due to "Operation not supported". This maybe because my application is on a NFS mounted partition.

Answer 1

Try setting ipc_key_add_uid in your .asoundrc file. see ALSA documentation on pcm plugins for more information.