On Sat, Aug 3, 2013 at 11:30 PM, James Stone <jamesmst...@gmail.com> wrote:
>
> On Aug 3, 2013 9:28 PM, "Alan Stern" <st...@rowland.harvard.edu> wrote:
>>
>> On Fri, 2 Aug 2013, James Stone wrote:
>>
>> > > OK - here's a trace with all patches applied. It didn't occur when
>> > > the
>> > > webcam was re-plugged this time..  This one happened when opening the
>> > > trace file while it was being written to. I hope this is OK? It seems
>> > > to be a fairly consistent way to get the audio to hang up, but I'm
>> > > not
>> > > sure it is such a "natural" way to induce the bug tho?
>> > >
>> >
>> > Another trace - this time occurring when plugging in a usb game
>> > controller.. so I guess the webcam isn't the culprit!
>>
>> Traces that show a delay of less than 1 ms aren't very interesting, in
>> general.  However, they do show that the scheduling code in ehci-hcd
>> takes longer than it should (although it probably runs more quickly
>> when tracing isn't turned on).
>>
>> I've known for a long time that the scheduler in ehci-hcd needs to be
>> rewritten completely.  It's a big job, so I've been avoiding it...
>>
>> Some event that causes a whole bunch of those new "underrun" messages
>> in the system log would be worth seeing.
>>
>
> All of these traces were associated with underrun messages but it seems
> they
> are not really capturing anything useful.

Don't know if these syslog errors are also related?

Aug  3 18:34:06 blueberry kernel: [35122.375869] retire_capture_urb:
3189 callbacks suppressed

James
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