From mboxrd@z Thu Jan  1 00:00:00 1970
From: Pavel Machek <pavel@ucw.cz>
Subject: Re: what handles disk drive(s) shutdown?
Date: Sat, 11 Feb 2006 00:06:33 +0100
Message-ID: <20060210230633.GB1947@elf.ucw.cz>
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To: "Randy.Dunlap" <rdunlap@xenotime.net>
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List-Id: linux-pm@vger.kernel.org

On P=E1 10-02-06 14:59:58, Randy.Dunlap wrote:
> On Fri, 10 Feb 2006, Pavel Machek wrote:
>=20
> > Hi!
> >
> > > in Documentation/power/devices.txt, I read:
> > >
> > > <quote>
> > > System shutdown -- at least disks need to be spun down, or data may=
 be
> > > lost. Quiesce devices, just to make life easier for BIOS. event =3D
> > > FREEZE, flags =3D SYSTEM_SHUTDOWN
> > > </quote>
> > >
> > > Is this actually done somewhere?  I can't find /SYSTEM_SHUTDOWN/
> > > in any kernel .h or .c files.
> >
> > I think we do FREEZE during shutdown, but flags never got
> > implemented. It seems nobody really needs them, so...
>=20
> I'm not particular about the flags, but I do have a case of
> needing to do what the comment describes:  spin down disks
> during shutdown.  Can anyone suggest how that should be done?
>=20
> [I'm currently adding code to use register_reboot_notifier()
> and keeping a table of SATA/PATA controllers/channels for use
> at shutdown...]

No, that is not the right way.

void kernel_shutdown_prepare(enum system_states state)
{
        notifier_call_chain(&reboot_notifier_list,
                (state =3D=3D SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
        system_state =3D state;
        device_shutdown();
}

device_shutdown() should do it, AFAICT.

If you want to listen to such event, you should just register your
driver with sysfs and implement .suspend() method. But I believe PATA
does that already...
								Pavel
--=20
Web maintainer for suspend.sf.net (www.sf.net/projects/suspend) wanted...