I have been able to resolve the previously reported errors by setting the
environment variable for ALSA configuration file on the target filesystem of
the embedded platform.
ALSA_CONFIG_PATH=/usr/share/alsa/alsa.conf
However, I do not hear any audio from USB sound device with speaker-test or
aplay:
/home/saurav # aplay -D plughw:0,0 Vincent.wav
Playing WAVE 'Vincent.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
Aborted by signal Interrupt...
.....
/home/saurav # speaker-test
speaker-test 0.0.8
Playback device is plughw:0,0
Stream parameters are 48000Hz, S16_BE, 1 channels
Using 16 octaves of pink noise
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 96 to 262144
Period size range from 48 to 131072
Periods = 4
Buffer time size 2525
To choose buffer_size = 262144
To choose period_size = 65536
was set period_size = 65536
was set buffer_size = 262144
0 - Front Left
Time per period = 0.276507
0 - Front Left
Time per period = 0.273772
0 - Front Left
......
Upon using arecord for recording, I get an error:
/home/saurav # arecord -D plughw:0,0 -t wav file.wav
Recording WAVE 'file.wav' : Unsigned 8 bit, Rate 8000 Hz, Mono
arecord: xrun:1077: read/write error, state = PREPARED
Is this problem related to a low-level driver issue which may not be working
well on target platform? Could there be a DMA related issue as the samples
don't seem to be transferred to the USB audio device.
Best Regards
Saurav
----- Original Message -----
From: Saurav Sahu
To: alsa-user@lists.sourceforge.net
Sent: Thursday, March 06, 2008 4:28 PM
Subject: ALSA utility aplay/arecord error
Hello
I am working towards using ALSA for playback and capture on an embedded
platform running Linux. The kernel uses ALSA driver version 1.0.10rc1. I had
manually built and installed ALSA library (v1.0.10) and ALSA utilities
(v1.0.10) for the target platform filesystem. I have a USB audio device
(C-Media) connected to the USB port of the board and it seems to be
successfully successfully detected by the driver.
~ # ls /dev/snd -l
crw-rw---- 1 root root 220, 0 Jan 1 00:00 controlC0
crw-rw---- 1 root root 220, 24 Jan 1 00:00 pcmC0D0c
crw-rw---- 1 root root 220, 16 Jan 1 00:00 pcmC0D0p
crw-rw---- 1 root root 220, 1 Jan 1 00:00 seq
crw-rw---- 1 root root 220, 33 Jan 1 00:00 timer
~ # cat /proc/asound/cards
0 [default ]: USB-Audio - C-Media USB Audio Device
C-Media USB Audio Device at usb-asic-ehci-1.4, full
speed
~ # cat /proc/asound/devices
1: : sequencer
16: [0- 0]: digital audio playback
24: [0- 0]: digital audio capture
0: [0- 0]: ctl
33: : timer
~ # cat /proc/asound/card0/stream0
C-Media USB Audio Device at usb-asic-ehci-1.4, full speed : USB Audio
Playback:
Status: Stop
Interface 1
Altset 1
Format: S16_LE
Channels: 2
Endpoint: 1 OUT (ADAPTIVE)
Rates: 48000, 44100
Capture:
Status: Stop
Interface 2
Altset 1
Format: S16_LE
Channels: 1
Endpoint: 2 IN (ASYNC)
Rates: 48000, 44100
However, when I run ALSA utilities like aplay, arecord or speaker-test, I
observe errors opening the hardware device which may be related to the
configuration on the filesystem.
~ # aplay -l
**** List of PLAYBACK Hardware Devices ****
ALSA lib control.c:817:(snd_ctl_open_noupdate) Invalid CTL hw:0
aplay: device_list:230: control open (0): No such file or directory
aplay: conf.c:3109: snd_config_update_free: Assertion `update->count > 0 &&
update->finfo' failed.
Aborted (core dumped)
~ #
/home/saurav # aplay -D plughw:0,0 winxp.wav
ALSA lib pcm.c:2099:(snd_pcm_open_noupdate) Unknown PCM plughw:0,0
aplay: main:544: audio open error: No such file or directory
/home/saurav #
/home/saurav #
/home/saurav # speaker-test
speaker-test 0.0.8
Playback device is plughw:0,0
Stream parameters are 48000Hz, S16_BE, 1 channels
Using 16 octaves of pink noise
ALSA lib pcm.c:2099:(snd_pcm_open_noupdate) Unknown PCM plughw:0,0
Playback open error: -2,No such file or directory
speaker-test: conf.c:3109: snd_config_update_free: Assertion `update->count >
0 && update->finfo' failed.
Aborted (core dumped)
/home/saurav #
Are these errors from ALSA utility/library due to the detection of hardware,
ALSA configuration files or something else related to my target device
filesystem?
Thanks in advance for any help. Do let me know if you need any more details.
Best Regards
Saurav
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