After talking again to pulseaudio developers, they are sure that the bug is in ALSA. And they are also sure that this bug will be fixed here rather than by ALSA developers. Of course I still haven't understood what should be done.
** Changed in: alsa-driver (Ubuntu) Status: New => Incomplete -- When volume <= 15% the alsa master is at 0% https://bugs.launchpad.net/bugs/448528 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs