Re: Weird hard disk noise on shutdown (bug #7674)

[Rob Landley <rob@landley.net>]

On Tuesday 15 May 2007 5:08 pm, Dave Jones wrote:
> On Mon, May 14, 2007 at 07:32:43PM +0200, Tejun Heo wrote:
>  > Francesco Pretto wrote:
>  > > 2007/5/4, Tejun Heo <htejun@gmail.com>:
>  > >> Yeap, the third iteration of the patch just got submitted.
>  > >>
>  > >>   http://thread.gmane.org/gmane.linux.ide/18485
>  > >>
>  > >> Unfortunately, there doesn't seem to be an easy way out.  We'll need
>  > >> userland shutdown(8) update.
>  > >>
>  > >> -- 
>  > >> tejun
>  > >>
>  > > 
>  > > Ok, i can't understand if the patch will be included in 2.6.22 (i
>  > > didn't see it in the Andrew Morton merge plan). However, if you can
>  > > confirm the inclusion, i can send bug reports for ubuntu and gentoo. I
>  > > can even send an email to Miquel van Smoorenburg, who should be the
>  > > mainstream sysvinit developer (and probably the last maintainer).
>  > 
>  > Okay, the patch made upstream and webpage posted.
>  > 
>  >  http://linux-ata.org/shutdown.html
> 
> There's a typo..
> 
> "Check whether /sys/modules/libata/parameters/spindown_compat  exists. If it 
does, write 0 to it."
> 
> should be /sys/module/libata/parameters/spindown_compat
> 
> (no 's' after module)

Um, hang on.  So libata can't reliably turn the system off without data loss 
and potential damage to hardware unless userspace goes through a special song 
and dance?  And this is _not_ considered a defect in the kernel?

Why?

(Is there any other piece of hardware that needs userspace to quiesce it just 
so the _off_switch_ can take effect?  Yes, I read both the gmane thread and 
the linux-ata.org link.  I used to maintain the busybox halt/reboot/poweroff 
commands, although I don't anymore.  That just called reboot(), and this 
worked.)

Why on _earth_ does complicating software suspend add extra requirements to 
actual shutdown?  Since when does the shutdown command have to enumerate 
attached block devices?  If anything this would belong in umount -a, but that 
doesn't care about the hardware of the underlying block devices and 
SHOULDN'T...

I'm confused.  Could someone please explain?

Rob