[alsa-devel] hw_params function and OSS emulation

Timur Tabi timur at freescale.com
Thu Aug 23 00:08:18 CEST 2007

Takashi Iwai wrote:

> The purpose of prepare callback is to make the PCM stream ready to
> start.  (The trigger callbacks are supposed to be just triggering, not
> preparing the stream.)
> Usually, once after the PCM is triggered, the registers are no
> longer as same as the beginning.  If you want to stop and restart the
> stream, you'll very likely to reset the registers again.  That's why
> prepare is called again.  (Or, your driver is always go-or-die? :)

I thought you meant that the .prepare() function can be called multiple times 
*in a row*, like .hw_params() is.  But I guess that's not what you meant.

Timur Tabi
Linux Kernel Developer @ Freescale

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