After upgrading from wheezy to jessie, pulseaudio failed to produce sound suddenly.
I moved back to ALSA and have been running it almost half year.
I installed pulseaudio again, spent few hours to troubleshoot about no sound. Apparently pavucontrol was not able to access pulseaudio server showing "establishing ..." message. So I suspected that there is access control issue. Debian Wiki page does not say about it.
http://www.freedesktop.org/wiki/Softwar ... fectSetup/Should users be in the "audio" group?There are three kind of distributions: 1) those who control access to the sound card by adding users to the "audio" group, 2) those who use udev (or HAL) and ConsoleKit to dynamically give access to the currently "active" user, but allow overriding that using the "audio" group and 3) those who don't use the "audio" group at all, but rely solely on HAL+ConsoleKit to grant access to the sound card.
To find out which group your distribution belongs to, run ls -l /dev/snd. If the permission field of many of the listed files contains a plus character in the end, like this:
crw-rw----+ 1 root audio 116, 7 Aug 2 08:57 pcmC0D0p
then your distribution most likely belongs to group 2 or 3. If the group of the file is "audio", as above, then the distribution belongs to group 2, otherwise it belongs to group 3.
If there was no plus character in the permission fields, like in this example:
crw-rw---- 1 root audio 116, 7 Aug 2 08:57 pcmC0D0p
then your distribution belongs to group 1.
Now that you know how your distribution does access control to the sound card, it's easy to determine whether you should put users to the "audio" group or not:
If your distribution belongs to group 1, you must put all users to the "audio" group or otherwise they can't access the sound card.
If your distribution belongs to group 2 or 3, you should make sure that no one is in the "audio" group. (If you plan running pulseaudio in the system-wide mode, then the special user "pulse" should still be in the "audio" group in order to have access to the sound card.) If your distribution belongs to group 1 or 2, fast user switching doesn't work properly if users are in the "audio" group.
Based on above information, in jessie audio is group 2.
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$ ls -l /dev/snd
total 0
drwxr-xr-x 2 root root 60 Aug 16 15:25 by-path
crw-rw----+ 1 root audio 116, 2 Aug 16 15:25 controlC0
crw-rw----+ 1 root audio 116, 6 Aug 16 15:25 hwC0D0
crw-rw----+ 1 root audio 116, 4 Aug 16 19:20 pcmC0D0c
crw-rw----+ 1 root audio 116, 3 Aug 16 19:33 pcmC0D0p
crw-rw----+ 1 root audio 116, 5 Aug 16 15:25 pcmC0D2c
crw-rw---- 1 root audio 116, 1 Aug 16 15:24 seq
crw-rw----+ 1 root audio 116, 33 Aug 16 15:25 timer
I checked my user account's all group and it has audio group.
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$ id penguin
uid=1000(penguin) gid=1000(penguin)
groups=1000(penguin),4(adm),5(tty),7(lp),20(dialout),24(cdrom),25(floppy),29(audio),30(dip),40(src),44(video),46(plugdev),108(netdev),109(bluetooth),110(lpadmin),114(scanner),106(pulse),126(debian-tor)
I removed my account from audio group. Start 'pulseaudio -D' in x-terminal.
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$ sudo deluser penguin audio
Removing user `penguin' from group `audio' ...
Done.
pulseaudio starts running again.
I really don't know.
Peace
