Am Donnerstag, 8. Oktober 2009 16:58:39 schrieb Alan Stern:
> On Thu, 8 Oct 2009, Oliver Neukum wrote:
> > Am Mittwoch, 7. Oktober 2009 23:34:12 schrieb Alan Stern:
> > > Other schemes could work, but to me it seems simplest to rely on a flag
> > > protected by a spinlock. The flag would mean "URBs are supposed to be
> > > queued unless we are suspended". It would be set by open and
> > > unthrottle, and cleared by close and throttle.
> >
> > 1. Why a spinlock?
>
> Because the amount of work involved seems too small for a mutex. But
> you could use a mutex if you wanted, since everything occurs in process
> context.
We have to submit URBs under that lock.
> > 2. Can we get by with only one flag?
>
> If all you want to do is answer a single question ("Should URBs be
> submitted") then a single flag should be all you need. Why, do you
> think more information will be necessary? You can always add more.
We have at least three reasons URBs should not be submitted.
- closure
- throttling
- suspension
Resume() should not submit if either closure or throttling are active,
neither should unthrottle() resubmit if closure or suspension are active.
Regards
Oliver
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