[MPlayer-dev-eng] [PATCH] ALSA AO, attempt both chunk sizes before failing

[Clemens Ladisch]

Andrew Calkin wrote:
> The attached patch has been sitting in the GeeXboX development tree
> since antiquity. Basically if it fails to set the period size with one
> of the values (1024 or 512), then it tries the other before bailing out.

>  	if ((err = snd_pcm_hw_params_set_period_size_near(alsa_handler, alsa_hwparams, 
>  							  &chunk_size, NULL)) < 0)

When it is not possible to set the given period size, this function just
sets a value that is as near as possible to the given value ("*_near").
This function fails only if cannot set _any_ value for the period size.

>  	  {
> -	    mp_msg(MSGT_AO,MSGL_ERR,MSGTR_AO_ALSA_UnableToSetPeriodSize,
> -			    chunk_size, snd_strerror(err));
> +	    chunk_size = 512 + 1024 - chunk_size;
> +	    if ((err = snd_pcm_hw_params_set_period_size(alsa_handler, alsa_hwparams, 
> +	                                                 chunk_size, 0)) < 0) {
> +	      mp_msg(MSGT_AO,MSGL_ERR,MSGTR_AO_ALSA_UnableToSetPeriodSize,
> +	      chunk_size, snd_strerror(err));
> +	    }
>  	    return 0;

This "return 0" will abort even if the second call succeeded.

Was there any situation where this patch was observed to make any difference?


Regards,
Clemens