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

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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.

Alan Stern




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