Re: Re: Hotplug events during sleep transition

Pavel Machek
2005-12-23T21:28:32Z

On Pá 23-12-05 16:22:44, 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.
>
> I haven't actually tried it yet, so maybe there's a hidden gotcha.

That would mean quite a lot of "extra" events delivered to userspace,
no? ... no, actually not, that should be okay. "resume during
suspend" events will be discarded, because they'll not make it into
on-disk image, so userspace will get single unplug/replug events after
resume. That's okay.

OTOH I do not think try_to_freeze() is going to make it. Process
freezing is one-time action, so if you start new thread,
try_to_freeze() will not attempt to freeze it.
Pavel
--
Thanks, Sharp!