Re: Disk spin down issue on shut down/suspend to disk

[Rafael J. Wysocki]

On Thursday, 9 August 2007 17:06, Pavel Machek wrote:
> Hi!
> 
> > >> Oh... crap, so acpi wants to sync cache on shutdown.  I wonder whether
> > >> it spins down the disk correctly.  Does emergency unload count increase
> > >> after each power down?  Also, please post the result of 'dmidecode'.
> > > 
> > > I know that my Compaq X1000-series laptop does do some kind of ACPI
> > > games with the disk on ACPI power off (I assume it is putting the disk
> > > in standby before power-off at least). It also does this if you boot
> > > into DOS, GRUB, etc. and then hit the power button. Could be if the disk
> > > is dumb enough to spin up for sync cache and standby when there is
> > > nothing to flush, and the kernel does its own standby, this could cause
> > > an extra spinup/down..
> > 
> > Yeah, that seems to be what's going on.  I don't think we have any other
> > choice than blacklisting those notebooks.  This is a mess.  How does the
> > other OS cope with this?
> > 
> > I'm thinking about using DMI vendor/product match to detect the affected
> > systems but I think it would be better to match the ACPI implementation
> > directly.  Is there a way to match specific ACPI implementation?
> 
> Well.. unless they use some SMM trick, it is ACPI AML code telling
> kernel to spin the disk down. I guess we could detect that, and simply
> ignore the request.

Please see: http://lkml.org/lkml/2007/8/8/187

Greetings,
Rafael
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