[alsa-devel] [PATCH v5 07/13] soundwire: Add stream configuration APIs

[Vinod Koul]

On Thu, Apr 26, 2018 at 09:30:16AM +0530, Sanyog Kale wrote:
> On Wed, Apr 25, 2018 at 03:09:17PM +0530, Vinod Koul wrote:
> > From: Sanyog Kale <sanyog.r.kale at intel.com>
> > 
> > Add APIs for prepare, enable, disable and de-prepare stream.
> > 
> > Signed-off-by: Sanyog Kale <sanyog.r.kale at intel.com>
> > Signed-off-by: Shreyas NC <shreyas.nc at intel.com>
> > Signed-off-by: Vinod Koul <vkoul at kernel.org>
> > ---
> >  drivers/soundwire/bus.c       |   9 ++
> >  drivers/soundwire/stream.c    | 246 ++++++++++++++++++++++++++++++++++++++++++
> >  include/linux/soundwire/sdw.h |   4 +
> >  3 files changed, 259 insertions(+)
> > 
> > +
> > +static int _sdw_deprepare_stream(struct sdw_stream_runtime *stream)
> > +{
> > +	struct sdw_master_runtime *m_rt = stream->m_rt;
> > +	struct sdw_bus *bus = m_rt->bus;
> > +	int ret = 0;
> > +
> > +	/* De-prepare port(s) */
> > +	ret = sdw_prep_deprep_ports(m_rt, false);
> > +	if (ret < 0) {
> > +		dev_err(bus->dev, "De-prepare port(s) failed: %d", ret);
> > +		return ret;
> > +	}
> > +
> > +	/* TODO: Update this during Device-Device support */
> > +	bus->params.bandwidth -= m_rt->stream->params.rate *
> > +		m_rt->ch_count * m_rt->stream->params.bps;
> > +
> 
> We should have kept zero bandwidth check here because there is no need
> to perform sdw_program_params when no stream is running on bus.

Looking at it I think it helps to program the calculated values, we may get
a new stream even before we get a chance to suspend. And frankly at bus, we
should not make any assumptions about suspend behaviour they may change with
platforms and archs :)

> 
> > +	/* Program params */
> > +	ret = sdw_program_params(bus);
> > +	if (ret < 0) {
> > +		dev_err(bus->dev, "Program params failed: %d", ret);
> > +		return ret;
> > +	}
> > +
> > +	return do_bank_switch(stream);
> 
> Change the state to DEPREPARE and then return.

good spot will fix

> 
> > +
> > +	stream->state = SDW_STREAM_DEPREPARED;
> > +
> > +	return ret;
-- 
~Vinod