On Tue, 13 Aug 2013, Daniel Mack wrote: > Hi Alan, > > On 13.08.2013 23:06, Alan Stern wrote: > > On Mon, 12 Aug 2013, Alan Stern wrote: > >> On Mon, 12 Aug 2013, Takashi Iwai wrote: > >> > >>> So... Clemens, Daniel, Eldad, could you guys review the latest version > >>> of Alan's patch? I'd love to sort this out for 3.12. > >> > >> Here's a revised version of the patch (still untested). The difference > >> is that this version tries always to keep a period's worth of bytes in > >> the USB hardware queue. This will provide better protection against > >> underruns when the period is larger than the queue's minimum > >> requirement. > > > > After more thought, I decided that patch does too much. It's not > > necessary to keep track of the number of packets. Instead, the driver > > should always try to keep as much data in the USB hardware queue as it > > is allowed to. > > > > In other words, there should be enough URBs so that an entire ALSA > > buffer can be queued at any time, subject only to the limit on the > > maximum number of URBs and packets. It doesn't make sense to allocate > > just enough URBs to cover a single period. > > > > Does this seem reasonable? > > I think so, yes. But I'd like to comment on the actual patch, and also > give it a try first of course. It took me some days to gather my setup > again, but if you send a revised version, I hope to be able to test it > in the next days. I can also test the revised patch on the weekend. My device uses implicit feedback though. Cheers, Eldad -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
