ALSA Plugin for XMMS2. Help wanted.

ALSA Plugin for XMMS2. Help wanted.

[Tobias Rundström]

Hello ALSA developers.

We have just released the first public version of XMMS2. This is  
developer release and aimed for persons who want to poke around in  
the sourcecode and help enhancing XMMS2. Since the release of DR1 we  
had numeros bug-reports against our alsa-plugin. We had fairly hard  
time trying to figure out how to use the API and cope with all error  
handling.

This is a call for help. We would like a senior ALSA developer look  
at our plugin and give us advice (or even write the code himself).  
The source is available from git at http://git.xmms.se/ - direct link  
to the alsa plugin here :
http://git.xmms.se/? 
p=xmms2.git;a=blob;h=c6a9e2c5e0ee6e916c71c90cc924e55df4a1e61d;hb=08c7a63 
cf1cbbc708304675f365e1538e55b4a97;f=src/plugins/alsa/alsa.c

If you are willing to help please contact me or join our IRC channel  
on Freenode #xmms2 and we will supply the current issues we are  
seeing. Any help on this will be highly appriciated.

Greetings
XMMS Team via Tobias



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Re: ALSA Plugin for XMMS2. Help wanted.

[Clemens Ladisch]

Tobias Rundström wrote:
> This is a call for help. We would like a senior ALSA developer look
> at our plugin and give us advice (or even write the code himself).

I guess the second value in the rates array should be 11025 and not
12025.

The default value for mixer_dev should be "default" and not "hw:0".

Without the SND_PCM_NONBLOCK flag, the snd_pcm_open call will block
until the device is available instead of returning an error.  If you
add this flag, call snd_pcm_nonblock(..., 0) afterwards to make sure
that the later write calls will block. write ca

I didn't find any other obvious issues.

> We had fairly hard time trying to figure out how to use the API
> and cope with all error handling.

It isn't obvious what happens when there is an unrecoverable error
(if, e.g., a USB device gets unplugged).  I guess in such a case XMMS
should stop playing, but it seems xmms_alsa_write cannot actually
signal an error.


HTH
Clemens



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Re: ALSA Plugin for XMMS2. Help wanted.

[Clemens Ladisch]

Tobias Rundström wrote:
> [...]

Some further remarks:

In the call to xmms_plugin_new, the string literal in the last
parameter includes several tab characters from the beginning of the
second line.

xmms_alsa_probe_modes should check the return value of snd_pcm_open,
and use SND_PCM_NONBLOCK, too.

xmms_alsa_buffer_bytes_get should check for return values other than
-EPIPE.


HTH
Clemens



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Re: ALSA Plugin for XMMS2. Help wanted.

[Tobias Rundström]

Clemens Ladisch wrote:
> Tobias Rundström wrote:
> 
>>[...]
> 
> 
> Some further remarks:
> 
> In the call to xmms_plugin_new, the string literal in the last
> parameter includes several tab characters from the beginning of the
> second line.
> 
> xmms_alsa_probe_modes should check the return value of snd_pcm_open,
> and use SND_PCM_NONBLOCK, too.
> 
> xmms_alsa_buffer_bytes_get should check for return values other than
> -EPIPE.

Thanks for all help. We have started to work on ALSA again, some of the 
fixes you suggested was included in XMMS2 DR1.1 that was released earlier.

We realized that all our current plugins where blocking during 
open/probing. This will change to DR2. Thanks for noticing.

Visit http://git.xmms.se/?p=xmms2.git;a=summary to track our progress.

Greetings
Tobias


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