[mythtv-users] OT: Sound device ownership

Jeff Wormsley daworm at comcast.net
Sun Apr 16 02:07:01 UTC 2006


As part up updating my mythbox, and due to some weird yum errors, I had 
to uninstall ALSA.  I fixed the other problems, and reinstalled the 
latest ALSA, and now I can only play audio as root.  Obviously, this 
isn't good as I need to play as user mythtv (which worked fine before).  
I noticed I had no 'audio' group, so I created one and added root and 
mythtv to it, and set the ownership via chown to all of the audio 
devices I could think of in /dev, but I still can only play audio as 
root.  Anyone have any ideas?

kernel: 2.6.16-1.2069_FC4smp
myth: mythtv-suite-0.19-57 via ATRPMS
alsa kernel module: alsa-kmdl-2.6.16-1.2069_FC4smp-1.0.11-46_rc5.rhfc4
alsa driver:  alsa-driver-1.0.11-46_rc5.rhfc4

Souncard is an SBLive! Value (one of the normal ones, with a hacked on 
SPDIF cable, which works fine, but now only as root)

Sound card lspci info:
02:02.0 Multimedia audio controller: Creative Labs SB Live! EMU10k1 (rev 07)
        Subsystem: Creative Labs: Unknown device 8032
        Flags: bus master, medium devsel, latency 32, IRQ 16
        I/O ports at b800 [size=32]
        Capabilities: [dc] Power Management version 1

Sound card lsmod info:

[root at mythtv mythtv]# /sbin/lsmod
Module                  Size  Used by
snd_seq_midi           11424  0
snd_emu10k1_synth      10624  0
snd_emux_synth         36224  1 snd_emu10k1_synth
snd_seq_virmidi        10368  1 snd_emux_synth
snd_seq_midi_emul      10112  1 snd_emux_synth
snd_emu10k1           117796  1 snd_emu10k1_synth
snd_rawmidi            25504  3 snd_seq_midi,snd_seq_virmidi,snd_emu10k1
snd_ac97_codec         90656  1 snd_emu10k1
snd_ac97_bus            6016  1 snd_ac97_codec
snd_seq_dummy           7044  0
snd_seq_oss            34916  0
snd_seq_midi_event     10496  3 snd_seq_midi,snd_seq_virmidi,snd_seq_oss
snd_seq                51020  9 
snd_seq_midi,snd_emux_synth,snd_seq_virmidi,snd_seq_midi_emul,snd_seq_dummy,snd_seq_oss,snd_seq_midi_event
snd_pcm_oss            40608  0
snd_mixer_oss          19968  1 snd_pcm_oss
snd_pcm                83204  3 snd_emu10k1,snd_ac97_codec,snd_pcm_oss
snd_seq_device         11532  8 
snd_seq_midi,snd_emu10k1_synth,snd_emux_synth,snd_emu10k1,snd_rawmidi,snd_seq_dummy,snd_seq_oss,snd_seq
snd_timer              24324  3 snd_emu10k1,snd_seq,snd_pcm
snd_util_mem            7936  2 snd_emux_synth,snd_emu10k1
snd_hwdep              11652  2 snd_emux_synth,snd_emu10k1
snd                    51424  14 
snd_emux_synth,snd_seq_virmidi,snd_emu10k1,snd_rawmidi,snd_ac97_codec,snd_seq_dummy,snd_seq_oss,snd_seq,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_seq_device,snd_timer,snd_hwdep
soundcore              13729  1 snd
emu10k1_gp              7873  0
gameport               19529  2 emu10k1_gp
snd_page_alloc         12040  2 snd_emu10k1,snd_pcm

Permissions/ownership/group
crw-rw-rw-  1 mythtv audio 14, 0 Apr 15 16:27 /dev/mixer
crw-rw-rw-  1 mythtv audio 14, 1 Apr 15 16:27 /dev/sequencer
crw-rw-rw-  1 mythtv audio 14, 3 Apr 15 16:27 /dev/dsp
crw-rw-rw-  1 mythtv audio 14, 4 Apr 15 16:27 /dev/audio

Attempting to play wav as user mythtv:

[mythtv at mythtv ~]$ /usr/bin/aplay -Dmixed-digital 
"/usr/share/sounds/KDE_Startup.wav"
ALSA lib pcm_dmix.c:832:(snd_pcm_dmix_open) unable to open slave
aplay: main:542: audio open error: Permission denied

Attempting to play wav as user root (via su):

[root at mythtv mythtv]# /usr/bin/aplay -Dmixed-digital 
"/usr/share/sounds/KDE_Startup.wav"                                                                      
Playing WAVE '/usr/share/sounds/KDE_Startup.wav' : Signed 16 bit Little 
Endian, Rate 22050 Hz, Mono

Anyone have any ideas what I've missed/done wrong?

TIA,
 Jeff.



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