[alsa-devel] [PATCH 2/3] ASoC: support all possible sample rates in the WM8776 driver

Tabi Timur-B04825 B04825 at freescale.com
Fri Sep 16 01:06:53 CEST 2011

Mark Brown wrote:

> This isn't what happens at all.  The constraints set in the DAIs
> generally just list all the sample rates the device can possibly
> support, there's no dynamic information injected into the subsystem
> about what's supported.  This is because in many systems the various
> clock rates are dynamically controlled and so the clocks are adjusted to
> reflect the sample rates the application layer wants.

IMHO, these two sentences contradict each other.

> As a result we
> never actually bother specifying the supported rates for the current
> clock at all, we just try to make the best of what we're given when it
> comes to configuring which is a rather different thing.

But why would you do that?  That just creates an artificial limitation on 
the list of supported sample rates.  If you include a set_sysclk() 
function in the codec driver, then you should always specify 
SNDRV_PCM_RATE_CONTINUOUS in snd_soc_dai_driver.rates.  To me, the two go 

Timur Tabi
Linux kernel developer at Freescale

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