Re: Re: Hotplug events during sleep transition

Nigel Cunningham
2005-12-23T22:09:56Z

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Hi.

On Sat, 2005-12-24 at 07:28, Greg KH wrote:
> On Fri, Dec 23, 2005 at 04:22:44PM -0500, Alan Stern wrote:
> > On Fri, 23 Dec 2005, Pavel Machek wrote:
> >
> > > Well, if you can find some elegant solution in the core, I think thats
> > > the best way.
> > >
> > > You could set system_state to "suspending" or something like that, and
> > > just if() out notifications in that case.
> >
> > How about simply adding a call to try_to_freeze() somewhere inside
> > kernel/kmod.c:____call_usermodehelper()? That ought to do pretty much
> > what I want, in theory. The hotplug processes would get frozen before
> > /sbin/hotplug is exec'ed.
>
> On modern distros, /sbin/hotplug is set to NULL, so this isn't an issue.
> We use netlink to send the data out, so this might not even be a problem
> anymore...

At resume time, prior to copying back the original kernel data, events
can and do occur.

FWIW, I've been using "if(freezer_is_on()) return 0" for a while in
call_usermodehelper_keys, to good effect.

Regards,

Nigel