Re: Audio I/O parameters

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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.

Alan Stern

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