Am Dienstag, 22. Mai 2007 18:50 schrieb Jiri Kosina:
> On Tue, 22 May 2007, Alan Stern wrote:
>
> > But if you kill the interrupt URB then there will be no more inputs and
> > hence nothing to generate any more output. Thus, when suspending you
> > should kill the inputs and wait for the outputs to drain (or else
> > explicitly plug the output queue). Then it will be safe to autoresume
> > whenever a new output queue entry arrives.
>
> Hi Alan,
>
> I think that this is unfortunately not true. Let's take system with
> multiple keyboards and their LEDs as an excellent example again. If you
> kill the interrupt URB, there is nothing what will prevent other keyboard
> (PS/2 or even USB keyboard, which is not yet suspended) to generate an
> input event (user presses CapsLock/NumLock at a 'right' time). Then you'll
> get out of sync, won't you?
That gives me an idea.
Resumption of a device has to be done in task context. So if I allocate
a private freezable work queue for HID resumption, the freezer would
guard against illicit resumptions, wouldn't it?
Regards
Oliver
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