Re: [PATCH] usb: core: devio: add ioctls for suspend and resume

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Am Montag, den 01.07.2019, 10:17 -0400 schrieb Alan Stern:
> On Mon, 1 Jul 2019, Oliver Neukum wrote:
> 
> > Am Donnerstag, den 27.06.2019, 09:52 -0400 schrieb Alan Stern:
> > 
> > > 
> > > Or maybe the WAIT_FOR_RESUME ioctl returns because there was a remote 
> > > wakeup.  In this case also you would call FORBID_SUSPEND.
> > > 
> > > In fact, you should call FORBID_SUSPEND _whenever_ WAIT_FOR_RESUME
> > 
> > Well, this kind of indicates that the original syscall should bump
> > the counter.
> 
> Perhaps it does, but...
> 
> > > returns, unless your program has decided not to use the device any more
> > > (in which case you don't care whether the device is suspended or
> > > resumed).
> > 
> > Then you should close the device.
> 
> Exactly.  Suppose WAIT_FOR_RESUME is interrupted and then the program
> closes the device.  There's no need to force the device back to full 
> power in this situation.

But that is the error case. You return an error code. The point of that
is to report that a syscall did not have all requested effects.

	Regards
		Oliver




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