snd_pcm_hw_param_first — refine config space and return minimum value
| int snd_pcm_hw_param_first ( | struct snd_pcm_substream * pcm, | 
| struct snd_pcm_hw_params * params, | |
| snd_pcm_hw_param_t var, | |
| int * dir ); | 
pcmPCM instance
paramsthe hw_params instance
varparameter to retrieve
dir
     pointer to the direction (-1,0,1) or NULL