[alsa-devel] [PATCH 3/4] pxa-ssp: don't touch ssp registers when stream is running

Daniel Mack daniel at caiaq.de
Wed Mar 4 21:39:11 CET 2009

On Wed, Mar 04, 2009 at 08:33:52PM +0000, Mark Brown wrote:
> > In pxa_ssp_set_dai_fmt(), don't modify the SSP registers in case the
> > stream is already running. With that patch applied, loop-thru tests like
> > 'acrecord -f cd | aplay -f cd' succeed.
> > +	/* we can only change the settings if the port is not in use */
> > +	if (ssp_read_reg(ssp, SSCR0) & SSCR0_SSE)
> > +		return 0;
> I'd expect an error to be reported here - if we needed to change the
> settings and can't things could go wrong.  Ideally it'd check to see if
> the DAI format was being changed and only error if it was.

In my tests, pxa_ssp_set_dai_fmt() was simply called twice, once for the
input, once for the ouput. Hence I believed a silent exit in such a case
fine. Does 'arecord -f cd | aplay -f cd' work for you?


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