[yocto] [meta-raspberrypi][question] how to setup alsa on rpi3?

[Piotr Lewicki]

On 21.10.2016 13:26, Tanu Kaskinen wrote:
> On Fri, 2016-10-21 at 12:08 +0200, Piotr Lewicki wrote:
>> Hi,
>>
>> I want to use aplay to play a sound on raspberry pi 3, but for some
>> reason it does not work for me.
>>
>> I have built a new "rpi-test-image" with only one difference from
>> original- I added "alsa-utils" to the image.
>>
>> My steps:
>>
>> 1. I ssh'd to the board with the built image,
>>
>> 2. downloaded wav sample ("wget
>> http://freewavesamples.com/files/Korg-Triton-Harmonica-C5.wav"),
>>
>> 3. enabled the sound kernel module ("modprobe snd-bcm2835"),
>>
>> 4. tried to play it with "aplay" tool.
>>
>>
>> It did not work and I got an error:
>>
>> root at raspberrypi3:~# aplay ./Korg-Triton-Harmonica-C5.wav
>> ALSA lib ../../alsa-lib-1.1.2/src/confmisc.c:767:(parse_card) cannot
>> find card '0'
>> ALSA lib ../../alsa-lib-1.1.2/src/conf.c:4371:(_snd_config_evaluate)
>> function snd_func_card_driver returned error: No such file or directory
>> ALSA lib ../../alsa-lib-1.1.2/src/confmisc.c:392:(snd_func_concat) error
>> evaluating strings
>> ALSA lib ../../alsa-lib-1.1.2/src/conf.c:4371:(_snd_config_evaluate)
>> function snd_func_concat returned error: No such file or directory
>> ALSA lib ../../alsa-lib-1.1.2/src/confmisc.c:1246:(snd_func_refer) error
>> evaluating name
>> ALSA lib ../../alsa-lib-1.1.2/src/conf.c:4371:(_snd_config_evaluate)
>> function snd_func_refer returned error: No such file or directory
>> ALSA lib ../../alsa-lib-1.1.2/src/conf.c:4850:(snd_config_expand)
>> Evaluate error: No such file or directory
>> ALSA lib
>> ../../../alsa-lib-1.1.2/src/pcm/pcm.c:2450:(snd_pcm_open_noupdate)
>> Unknown PCM default
>> aplay: main:786: audio open error: No such file or directory
> It looks like the default alsa device is configured to use card 0, but
> card 0 doesn't exist. What do "cat /proc/asound/cards" and "ls -l
> /dev/snd" print?
root at raspberrypi3:~# cat /proc/asound/cards
--- no soundcards ---
root at raspberrypi3:~# ls -al /dev/snd/
drwxr-xr-x    2 root     root            60 Oct 21 09:53 .
drwxr-xr-x   11 root     root         13200 Oct 21 09:53 ..
crw-rw----    1 root     audio     116,  33 Oct 21 09:53 timer


I wonder what is used by omxplayer that it works, but alsa does not.
>
> -- 
> Tanu
--
Piotr