On Wed, 27 Jan 2016, Doug Anderson wrote: > Alan, > > On Wed, Jan 27, 2016 at 1:34 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > On Wed, 27 Jan 2016, Doug Anderson wrote: > > > >> This patch should fix ya. > >> > >> FIXUP: FROMLIST: usb: dwc2: host: Manage frame nums better in scheduler > >> https://chromium-review.googlesource.com/324185 > > > > Hmmm. That fixed the problem of the polls occuring too frequently, but > > now I see again intervals that are larger than 256 ms. In the most > > recent test there are two intervals of 512 ms and one of 2048 ms. > > OK, good to know. Ugh. I'll have to see if I can reproduce that. If > I had to guess, though, I'd say that you're probably running into high > interrupt latency problems. Quite possibly. Would that delay the transfers by a full period or only by one frame? > Those problems would be worse on the > Raspberry Pi than on my system due to the significantly slower > processor. > > Can you confirm that these problems also were introduced by my series? > AKA: you never saw > 256 ms polls before my series and now you see > them? No, these problems were also present in the kernel without your patches. > Turning on scheduler tracing would probably be quite helpful at this > point. You can see > <https://chromium-review.googlesource.com/#/c/314254/>. If printing > even non-verbose traces to the console is too much, you could make > everything "trace_printk". You might also want > <https://chromium-review.googlesource.com/#/c/323308/>. Later... Alan Stern -- 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
