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SubjectRE: [linux-pm] Power management for SCSI
Being able to drop power on the disk on demand is a useful concept.

We do it, but need a number of custom patches in a number of places.

When the system WANTS to access the disk, it does what is necessary to
get the disk to spin up...

I'm not sure dropping disk power in a control way should trigger a
event --if everyone EXPECTS it.

I'm just looking for a more generic way to enable this...I'm going to be
looking a 2.6.26/27 for this soon...


> -----Original Message-----
> From: Alan Stern []
> Sent: Wednesday, August 13, 2008 4:39 PM
> To: Leisner, Martin
> Cc: Oliver Neukum; Linux-pm mailing list; kernel list;;
>; Pavel Machek; Stefan Richter
> Subject: RE: [linux-pm] Power management for SCSI
> On Wed, 13 Aug 2008, Leisner, Martin wrote:
> > Regarding these scsi suspend patches, there's a general
> > problem to drop power on disk devices on a running system.
> > I discussed it in:
> >
> >
> There's a much worse problem which that thread completely ignored:
> When you turn off power to a disk device, to the system it looks
like a
> hot-unplug event. Any mounted filesystems or memory mappings on
> disk will be lost.
> Alan Stern

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