http://fedoraproject.org/wiki/LubomirKundrak/SoundTroubleshooting

Seems like pulseaudio sound server is not running. Please try to launch it
manually. Do you use Gnome?

Yes, I am using Gnome. But I can reproduce the problem in KDE as well. I find
that pulseaudio server is running using:  ps aux |grep pulseaudio

Output:
suman     7975  0.0  0.2 219944  4452 ?        Sl   15:55   0:02
/usr/bin/pulseaudio --log-target=syslog

There are some error messages in: grep pulseaudio /var/log/messages

Last part of the output:
Apr 18 15:55:52 matrix pulseaudio[7975]: polkit.c: Failed to show grant dialog:
Unable to lookup exe for caller
Apr 18 15:55:52 matrix pulseaudio[7975]: polkit.c: PolicyKit responded with
'auth_admin_keep_always'
Apr 18 15:55:52 matrix pulseaudio[7975]: main.c: Called SUID root and
real-time/high-priority scheduling was requested in the configuration. However,
we lack the necessary priviliges:
Apr 18 15:55:52 matrix pulseaudio[7975]: main.c: We are not in group 'pulse-rt'
and PolicyKit refuse to grant us priviliges. Dropping SUID again.
Apr 18 15:55:52 matrix pulseaudio[7975]: main.c: For enabling real-time
scheduling please acquire the appropriate PolicyKit priviliges, or become a
member of 'pulse-rt', or increase the RLIMIT_NICE/RLIMIT_RTPRIO resource limits
for this user.
Apr 18 15:55:52 matrix pulseaudio[7975]: main.c: setrlimit(RLIMIT_NICE, (31,
31)) failed: Operation not permitted
Apr 18 15:55:52 matrix pulseaudio[7975]: main.c: setrlimit(RLIMIT_RTPRIO, (9,
9)) failed: Operation not permitted
Apr 18 15:55:52 matrix pulseaudio[7975]: alsa-util.c: Error opening PCM device
hw:0: No such file or directory
Apr 18 15:55:52 matrix pulseaudio[7975]: module.c: Failed to load  module
"module-alsa-sink" (argument: "device_id=0
sink_name=alsa_output.pci_8086_293e_alsa_playback_0"): initialization failed.


Is it any problem due to SELinux? What do you suggest me to look at?

By the way, the user (suman) is not a local user. The machine shares users with
a YP server (NIS). Can that be a source for this permission problem? How to
rectify it then?

NIS-users are de-facto local users. Do you log at the machine remotely, or you
are an active console user?
(Hint: Look at the document linked above for ck-list-sessions)

Created attachment 302943 [details]
Screen output of 'pulseaudio -vvv' followed by Ctrl-C

Yes, I am an active console user. Here are some of the outputs:
============================================================================
[suman@matrix ~]$ getfacl /dev/snd/pcmC0D0c
getfacl: Removing leading '/' from absolute path names
# file: dev/snd/pcmC0D0c
# owner: root
# group: root
user::rw-
user:suman:rw-
group::rw-
mask::rw-
other::---
=============================================================================
[suman@matrix ~]$ ck-list-sessions
Session1:
        uid = '507'
        realname = ''
        seat = 'Seat1'
        session-type = ''
        active = TRUE
        x11-display = ':0'
        x11-display-device = '/dev/tty7'
        display-device = ''
        remote-host-name = ''
        is-local = TRUE
        on-since = '2008-04-18T10:25:50Z'
=============================================================================
[suman@matrix ~]$ aplay -D hw:0 /usr/share/sounds/startup3.wav 
aplay: main:546: audio open error: No such file or directory
=============================================================================
The screen output of pulseaudio -vvv is being added as attachment
(pulseaudio.log). I had to use Ctrl-C to stop since it hanged.
=============================================================================
[root@matrix ~]# grep pulseaudio /var/log/messages

(last few lines ...)

Apr 18 15:55:52 matrix pulseaudio[7975]: polkit.c: Failed to show grant dialog:
Unable to lookup exe for caller
Apr 18 15:55:52 matrix pulseaudio[7975]: polkit.c: PolicyKit responded with
'auth_admin_keep_always'
Apr 18 15:55:52 matrix pulseaudio[7975]: main.c: Called SUID root and
real-time/high-priority scheduling was requested in the configuration. However,
we lack the necessary priviliges:
Apr 18 15:55:52 matrix pulseaudio[7975]: main.c: We are not in group 'pulse-rt'
and PolicyKit refuse to grant us priviliges. Dropping SUID again.
Apr 18 15:55:52 matrix pulseaudio[7975]: main.c: For enabling real-time
scheduling please acquire the appropriate PolicyKit priviliges, or become a
member of 'pulse-rt', or increase the RLIMIT_NICE/RLIMIT_RTPRIO resource limits
for this user.
Apr 18 15:55:52 matrix pulseaudio[7975]: main.c: setrlimit(RLIMIT_NICE, (31,
31)) failed: Operation not permitted
Apr 18 15:55:52 matrix pulseaudio[7975]: main.c: setrlimit(RLIMIT_RTPRIO, (9,
9)) failed: Operation not permitted
Apr 18 15:55:52 matrix pulseaudio[7975]: alsa-util.c: Error opening PCM device
hw:0: No such file or directory
Apr 18 15:55:52 matrix pulseaudio[7975]: module.c: Failed to load  module
"module-alsa-sink" (argument: "device_id=0
sink_name=alsa_output.pci_8086_293e_alsa_playback_0"): initialization failed.
================================================================================

Apr 18 15:55:52 matrix pulseaudio[7975]: alsa-util.c: Error opening PCM device
hw:0: No such file or directory

I am wondering if you can strace pulseaudio -vvv and attach the output here?

Created attachment 302949 [details]
Output of 'strace pulseaudio -vvv' followed by Ctrl-C

open("/dev/snd/pcmC0D2p", O_RDWR|O_NONBLOCK) = -1 ENOENT (No such file or directory)


Hmm, seems to be some alsa problem when we try to open hw:0. Reassigning.

Please try "aplay -D hw:0,0 /usr/share/sounds/startup3.wav"

/dev/snd/pcmC0D2p is hw:0,2 (maybe a digital output?)

anyway, please attach output of "aplay -l"

No response from reporter.