Hmm...I was trying to understand this power save argument. I tried to
figure out a "typical" URB size by just plugging my headset in, and I saw wMaxPacketSize being 96 and/or 192 bytes.
Then, MAX_PACKS is set to either 6 (or 48 for USB 2.0 devices, but this
is just a headset).
Can this be correct? Does it mean that we are getting interrupts every
192 * 6 bytes (i e, every 6 ms for a 48kHz/stereo/16bit stream)?
Do this mean that the driver report exact one period only when period size is multiple of wMaxPackerSize ?
Using other period size give bad result , the driver use variable period size
hw_ptr does not always at period boundary , seem more like DSP_CAP_BATCH
From the result , minimum and maximum time difference bewteen hw_ptr change
can varies from 20% to 400%