[alsa-devel] [PATCH] ASoC: AMD: Add delay before starting to capture

[Agrawal, Akshu]

On 1/4/2019 5:57 PM, Mark Brown wrote:
> On Thu, Jan 03, 2019 at 10:18:13AM +0000, Agrawal, Akshu wrote:
>> On capture through dmic we observe a glitch at the start of record.
>> This is because we start capturing even before dmic is ready to send
>> out data. The glitch seen last for ~20msec.
>>
> 
>> +	/*
>> +	 * On some platforms, it takes ~20 msec for PDM DMICs and ADAU7002
>> +	 * to settle and start producing proper audio data.
>> +	 */
>> +	msleep(ADAU7002_DELAY_MS);
> 
> If the delay is required for external components to start up the delay
> should be going in the drivers for those components rather than in the
> driver for the CPU side, that way other systems using those components
> get the benefit and non-affected boards don't pay the cost.  There's
> already some support for this in the DMIC driver at least.
> 

Agreed, we can use the similar to wakeup_delay in dmic driver in our
codec driver. Will post the patch on same lines.

Thanks,
Akshu