[alsa-devel] [PATCH v2 1/6] ASoC: Intel: Add helper to poll register for DSP status

[Mark Brown]

On Thu, Jul 09, 2015 at 09:57:41AM +0530, Vinod Koul wrote:
> On Wed, Jul 08, 2015 at 07:36:21PM +0100, Mark Brown wrote:

> > > +	for (time = 0; time < timeout; time++) {
> > > +		if ((sst_dsp_shim_read_unlocked(ctx, offset) & mask) == expected_value)
> > > +			break;
> > > +
> > > +		mdelay(1);
> > > +	}

> > mdelay() not msleep()?  If we're waiting for multiple miliseconds that
> > could be lots of busy waiting.

> Usually this should get reflected in 1st iteration as the register update
> would get updated farrily quickly. msleep will add up lots of latency to
> this.

A common approach for that is to do a busy wait for say the first
milisecond (perhaps polling more often too) and then fall back to
something sleepy if things are slow.
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