Re: [PATCH -mm 6/7] PM: Remove power_state.event checks from suspendcore code

From: Alan Stern
Date: Thu Jun 14 2007 - 22:00:46 EST


On Fri, 15 Jun 2007, Rafael J. Wysocki wrote:

> On Thursday, 14 June 2007 16:21, David Brownell wrote:
> > On Wednesday 13 June 2007, Rafael J. Wysocki wrote:
> > > From: Rafael J. Wysocki <rjw@xxxxxxx>
> > >
> > > The suspend routines should be called for every device during a system sleep
> > > transition, regardless of the device's state, so that drivers can regard these
> > > method calls as notifications that the system is about to go to sleep, rather
> > > than as directives to put their devices into the 'off' state.
> >
> > Did you audit all the drivers to make sure this won't break things?
> > Like for example through inappropriate pci_save_state() calls?
>
> I did, but not very carefully.
>
> > I'd really expect this patch would break things...
>
> Well, in that case I'll have a closer look at them.

It might not be all that bad. One would expect problems to occur only
in cases where devices were already suspended at the time of a system
sleep transition. Since relatively few drivers currently implement
runtime PM -- and those that do are likely to be more careful about
not blindly making state changes -- there might not be too much
trouble.

Alan Stern

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