RE: [alsa-devel] [PATCH] ASoC: da7219: check SRM lock in trigger callback

[Lu, Brent]

> 
> Am not going to make myself popular here. It's MCLK and FSYNC (or WCLK as
> it's termed for our device) that is required for SRM to lock in the PLL.
> 
> So far I've not found a way in the codec driver to be able to get around this.
> I spent a very long time with Sathya in the early days (Apollo Lake) looking at
> options but nothing would fit which is why I have the solution that's in place
> right now. We could probably reduce the number of rechecks before
> timeout in the driver but that's really just papering over the crack and there's
> still the possibility of noise later when SRM finally does lock.

Hi Adam,

For Google CTS requirement (200ms cold output latency), we plan to upload a
patch which reduces the recheck number to 4 and interval to 20ms so the total
delay here would be 80ms for our platform. We think the time is still sufficient
for other platforms to generate a stable WCLK and for the codec SRM to lock but
still needs your confirmation. How do you think?


Regards,
Brent