[alsa-devel] [PATCH 02/10] ALSA: dice: wait for ensuring phase lock

[Takashi Sakamoto]

Hi Clemens,

On Dec 12 2015 20:42, Clemens Ladisch wrote:
> Takashi Sakamoto wrote:
>> Some users have reported that their Dice based models generate packet
>> discontinuity at the beginning of streaming. When standing on an
>> assumption that the value of SYT field in transferred AMDTP packet comes
>> from phase lock circuit, this comes from phase unlocking with current
>> clock source. Just waiting for dice notification is not enough to prevent
>> from packet discontinuity.
>>
>> This commit checks the register of phase lock after clock state change for
>> this purpose.
> 
> Is this patch actually known to help?
> 
> This discontinuity could also come from an unexpected initial DBC value.
> I think it would be a good idea to unconditionally enable
> CIP_SKIP_INIT_DBC_CHECK for all devices.

This issue also occurs on my ImpactTwin. Today, I dropped this patch and
tried re-generate this issue, then I cannot regenerate it.

As long as I tested, the deferred registration has an effect for this
issue. I guess that the beginning of packet streaming is envolved to the
end of hardware initialization, then discontinuity occurs.

I decide to drop this patch from next post, thanks to address it.


Regards

Takashi Sakamoto