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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 -----
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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