Re: [linux-pm] [PATCH] hibernation should work ok with memory hotplug

Nigel Cunningham
2008-11-06T09:26:58Z

Hi.

On Thu, 2008-11-06 at 18:12 +0900, KAMEZAWA Hiroyuki wrote:
> On Thu, 6 Nov 2008 10:12:18 +0100
> Pavel Machek <pavel@suse.cz> wrote:
>
> > > On Thu, 6 Nov 2008 09:14:41 +0900
> > > KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
> > >
> > > > Ok, please consider "when memory hotplug happens."
> > > >
> > > > In general, it happens when
> > > > 1. memory is inserted to slot.
> > > > 2. the firmware notifes the system to enable already inserted memory.
> > > >
> > > > To trigger "1", you have to open cover of server/pc. Do you open pc while the system
> > > > starts hibernation ? for usual people, no.
> > > >
> > > > To trigger "2", the user have special console to tell firmware "enable this memory".
> > > > Such firmware console or users have to know "the system works well." And, more important,
> > > > when the system is suspended, the firmware can't do hotplug because the kernel is sleeping.
> > > > So, such firmware console or operator have to know the system status.
> > > >
> > > > Am I missing some ? Current linux can know PCI/USB hotplug while the system is suspended ?
> > > >
> > > *OFFTOPIC*
> > >
> > > I hear following answer from my friend.
> > >
> > > - hibernate the system
> > > => plug USB memory
> > > => wake up the system
> > > => panic.
> >
> > That should work. File a bugzilla if it does not.
> >
> > > - hibernate the system
> > > => unplug USB memory
> > > => wake up the sytem
> > > => panic.
> >
> > That should work ok as long as you unmount the drive first.
> > Pavel
> Ok. I'll confirm if I have a chance.
> Sorry for rumor.

Oh, sorry. I read what I expected instead of what was there - thought
you were still walking about plugging and unplugging memory.

Nigel