Re: [linux-pm] Re: [PATCH] PM: Acquire device locks on suspend

Rafael J. Wysocki
2008-01-07T00:47:48Z

On Monday, 7 of January 2008, Rafael J. Wysocki wrote:
> On Monday, 7 of January 2008, Johannes Berg wrote:
> > Rafael J. Wysocki wrote:
> >
> > >> I don't see anything wrong with it. All that will happen is that the
> > >> removal will start before the suspend and finish after the resume.
> > >
> > > In that case, we'll attempt to call the device's .suspend() and .resume()
> > > routines, but we shouldn't do that, IMHO.
> >
> > I don't see anything wrong with that since the driver must be prepared to
> > handle that even in the regular case, it's the only thing you can
> > guarantee: no more method calls after removal finishes. Am I totally
> > misunderstanding things?
>
> Well, we are towards the end of device removal at this point, having called
> bus_remove_device(dev) for example, but still we've got it on dpm_active ...
>
> This may not be technically wrong (ie. we should be able to recover from
> that), but it seems conceptually wrong and with pm_sleep_rwsem in place it
> can be avoided.

No, it can't, without major complications.

Well, I think I'll just send a patch that should work most of the time ...

Rafael