Takashi Iwai wrote:
> Clemens Ladisch wrote:
>> Takashi Iwai wrote:
>>> In the commit mentioned above, we changed the logic to take +25%
>>> frequency as the basis, and it my *reduce* if ep->maxpacksize is lower
>>> than that.
>>> OTOH, if ep->maxpacksize is sane, we can rely on it rather than the
>>> implicit +25% frequency. That said, maybe we can check
>>> ep->maxpacksize whether it fits within the expected range, then adapt
>>> it, or take +25% freq as fallback?
>> You are describing how the current code behaves. The +25% limit _is_
>> what the code takes as the expected range.
> Well, the question is what is the "sane" range. +25% doesn't fit for
> some devices.
The USB audio specification _requires_ that there is as little jitter
It's no surprise that some device violates the specification. But
we don't know what the actual error is; whether we could adjust the
packet size for this particular device only, or increase the limit
for all devices, or use a completely different workaround.
> If maxpacksize fits without +100% as this patch suggests, can we rely
> on it instead?
The packet size affect the following computations, like the number of
packets per URB. I don't know how bad the effects would be.