Re: [RFC] How to handle delays in isochronous transfers?

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Peter Chen wrote:
>> How should the lower USB layers handle delays in transferring
>> isochronous data?
>> I have seen reports from users where URB completion interrupts were
>> delayed by as much as 50 ms.
>>
>> What should we do to recover and re-synchronize?
>
> I am not sure if feedback endpoint is implemented at our ISO-transfer
> class driver.
> If it is implemented, the class driver will take responsible to speed up/slow
> down transferring according to the device's feedback information.

In such a situation, the delay is much bigger than the device's buffer,
so just sending more samples afterwards will not help.

Furthermore, if packets are lost, frequency feedback becomes impossible
because the device doesn't know how many samples were lost.


Regards,
Clemens

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