[LAU] Error enabling dmix with ALSA

Hi, I am trying to enable a software mixer (using ALSA and dmix) on an OMAP3 based embedded target board using the twl4030 codec. When I try to play audio using the command, # aplay -D playback rec.wav I am getting the following error: ALSA lib pcm_direct.c:1098:(snd_pcm_direct_initialize_poll_fd) unable to open timer 'hw:CLASS=3,SCLASS=0,CARD=0,DEV=0,SUBDEV=0' ALSA lib pcm_dmix.c:943:(snd_pcm_dmix_open) unable to initialize poll_fd aplay: main:546: audio open error: No such file or directory The contents of my /etc/asound.conf is given below. pcm.playback { type dmix ipc_key 2048 ipc_key_add_uid true ipc_gid 1 slave { rate 44100 pcm hw:0 } } I have tested it on two kernel versions, 2.6.22 and 2.6.29, but it fails on both. Playback and recording works fine if -D option is not provided. I also tried configuring ALSA (dmix) with a different configuration file which is given in the following link: http://amarok.kde.org/wiki/Setting_up_Dmix_for_ALSA # aplay -D plug:ossmix /mnt/Audio1_1.wav ALSA lib pcm_direct.c:1098:(snd_pcm_direct_initialize_poll_fd) unable to open timer 'hw:CLASS=3,SCLASS=0,CARD=0,DEV=0,SUBDEV=0' ALSA lib pcm_dmix.c:943:(snd_pcm_dmix_open) unable to initialize poll_fd aplay: main:546: audio open error: No such file or directory But as you can see the same error turns up again. What could be the cause of this error? Is the above error related to ALSA configuration (for dmix)? Do I need to patch the kernel or ALSA for using dmix? Please help me resolve this issue. Let me know if any more setup info is required. Thanks and Regards, Ruchi Sirauthiya. Some information I obtained from the proc filesystem is given below for your reference. ----------------------- For Linux kernel 2.6.29 ----------------------- [root@OMAP3 tests]# cat /proc/asound/version Advanced Linux Sound Architecture Driver Version 1.0.19 [root@OMAP3 tests]# cat /proc/asound/cards 0 [omap3evm ]: twl4030 - omap3evm omap3evm (twl4030) [root@OMAP3 tests]# omap-dss: Could not find exact pixel clock. Requested 25188 kHz, got 25187 kHz [root@OMAP3 tests]# cat /proc/asound/devices 2: : timer 3: [ 0- 0]: digital audio playback 4: [ 0- 0]: digital audio capture 5: [ 0] : control [root@OMAP3 tests]# cat /proc/asound/timers G0: system timer : 7812.500us (10000000 ticks) P0-0-0: PCM playback 0-0-0 : SLAVE P0-0-1: PCM capture 0-0-1 : SLAVE [root@OMAP3 tests]# cat /proc/asound/pcm 00-00: TWL4030 twl4030-0 : : playback 1 : capture 1 [root@OMAP3 tests]# cat /proc/asound/devices 2: : timer 3: [ 0- 0]: digital audio playback 4: [ 0- 0]: digital audio capture 5: [ 0] : control [root@OMAP3 tests]# cat /proc/asound/pcm 00-00: TWL4030 twl4030-0 : : playback 1 : capture 1 [root@OMAP3 tests]# cat /proc/asound/oss/devices 3: [0- 0]: digital audio 4: [0- 0]: digital audio [root@OMAP3 tests]# cat /proc/asound/oss/sndstat Sound Driver:3.8.1a-980706 (ALSA v1.0.19 emulation code) Kernel: Linux OMAP3 2.6.29-rc3-omap1 #1 Fri Jul 24 14:45:37 IST 2009 armv7l Config options: 0 Installed drivers: Type 10: ALSA emulation Card config: omap3evm (twl4030) Audio devices: 0: (DUPLEX) Synth devices: NOT ENABLED IN CONFIG Midi devices: NOT ENABLED IN CONFIG Timers: 31: system timer Mixers: NOT ENABLED IN CONFIG [root@OMAP3 tests]# aplay -D playback /mnt/Audio1_1.wav ALSA lib pcm_direct.c:1098:(snd_pcm_direct_initialize_poll_fd) unable to open timer 'hw:CLASS=3,SCLASS=0,CARD=0,DEV=0,SUBDEV=0' ALSA lib pcm_dmix.c:943:(snd_pcm_dmix_open) unable to initialize poll_fd aplay: main:546: audio open error: No such file or directory ----------------------- For Linux kernel 2.6.22 ----------------------- [root@OMAP3 tests]# cat /proc/asound/devices 2: : timer 3: [ 0- 0]: digital audio playback 4: [ 0- 0]: digital audio capture 5: [ 0] : control [root@OMAP3 tests]# cat /proc/asound/pcm 00-00: OMAP PCM : omap alsa pcm : playback 1 : capture 1 [root@OMAP3 tests]# cat /proc/asound/timers G0: system timer : 7812.500us (10000000 ticks) P0-0-0: PCM playback 0-0-0 : SLAVE P0-0-1: PCM capture 0-0-1 : SLAVE [root@OMAP3 tests]# cat /proc/asound/ /proc/asound/TWL4030/ /proc/asound/devices /proc/asound/timers /proc/asound/card0/ /proc/asound/hwdep /proc/asound/version /proc/asound/cards /proc/asound/pcm [root@OMAP3 tests]# cat /proc/asound/cards 0 [TWL4030 ]: OMAP_ALSA - TWL4030 TWL4030 /proc/asound/oss was not found in the proc file system when booted with kernel 2.6.22.