Re: Re: [PATCH] PM: Acquire device locks on suspend

On Monday, 7 of January 2008, Rafael J. Wysocki wrote:

On Monday, 7 of January 2008, Johannes Berg wrote:

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Rafael J. Wysocki wrote:

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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