I use Feisty with 2.6.20 kernel on AMD64 platform. I have discovered a similar problem and already reported it as Bug #115593 (now, when I've found this bug description, #115593 may be marked as a duplicate, but I don't know how to do it...). Today, when all sound applications hanged again I did one more debug session. I think, some application which used dmix was killed. I don't know dmix architecture, but I know that dmix uses semaphores and shared memory for IPC. If application which raised the semaphore exits without zeroing it (e.g. segfaults or is killed in another way), other applications will wait forever for the semaphore to lower (in my testing, semctl(sem_id, 0, GETZCNT) has returned 2). The presence of the semaphore may be checked from the command line: ipcs -s $IPC_KEY where $IPC_KEY contains the value of dmix' ipc_key option. The semaphore may be deleted with: ipcrm -S $IPC_KEY This return all sound applications to the working state.
IMO, the issue should be reported upstream and some watchdog should be implemented to overcome the deadlock when "important" process dies. Although I don't know the ALSA architecture, I think, changing just dmix may fix the bug (no need to touch other ALSA parts). Since the bug is present in the latest release, it should be reopened. -- alsa suddenly stopped working (dmix socket disappeared) https://bugs.launchpad.net/bugs/85157 You received this bug notification because you are a member of Ubuntu Bugs, which is the bug contact for Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
