[alsa-devel] Period time/size in adaptive USB - alignment to nrpacks?

Clemens Ladisch clemens at ladisch.de
Thu Dec 29 09:43:06 CET 2011

Pavel Hofman wrote:
>Now please see the wireshark screenshot at
>http://personal.educity.cz/dustin/wireshark.png . Frame 1197 is the last
>URB of the period, with 960 bytes only. Yet the time distance around it
>is again 8 ms (12.808-12.816-12.824). The expected 5 ms lag appears 2
>URBs later, between frames 1201 and 1203 (12.832-12.837), all holding
>1536 bytes.

Wireshark shows the URBs when they are submitted, which
is in the completion handler of some previous URB.
This means that the timing of the submission has no
relation with its size.


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