[alsa-devel] Need help fixing pop/click artifacts in an ASOC driver

[Dimitris Papavasiliou]

On 12/17/18 4:10 PM, Mark Brown wrote:
> On Mon, Dec 17, 2018 at 02:58:03PM +0200, Dimitris Papavasiliou wrote:
> 
>> In general the clocks need to be switched during the hw_params
>> callback (when the new callback specifies a new sample rate,
>> which needs the other clock) and, as far as I can see, this can
>> happen at more or less any time, i.e. in all power states and
>> regardless of whether the device is opened or closed.
> 
> It shouldn't be called while the stream is running, if it is it'd be
> entirely fine to just return an error.

It's not called while the stream is running, or at least I
haven't seen that happen.  It can be called though, while the
device is opened and fully powered up, for instance when
switching tracks during playback, where the next track has a
different sample rate.  This scenario is relatively frequent
during normal use of a DAC and can't be avoided, as far as I can
see.