[alsa-devel] snd_pcm_hardware structure

Adish Kuvelker adkuvi at gmail.com
Wed Jun 23 19:22:57 CEST 2010


Hello,

I am developing a ALSA driver for the AtlasIII AC'97 Controller. The
AC'97 Controller FIFO is arranged as 16 32-bit entries. My PCM data
would be 16-bit samples and the driver will cater to 2-front channel
audio. I have configured the snd_pcm_hardware members as follows:
.formats = SNDDRV_PCM_FMTBIT_S16_LE
.period_bytes_max = 4,
.period_bytes_min = 64,
As I would need a minimum of 4-byte sample to be transferred and the
"period_bytes_max" value has been set considering the maximum size of
the FIFO in bytes. Is my understanding correct in doing these
settings?

Secondly, I am having slight problems in understanding the
"snd_pcm_hardware" members periods_min and periods_max. Can anyone
throw some more light on this in addition to what is explained in the
"Writing an Audio Driver"?

Regards;
Aadish


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