lkml.org 
[lkml]   [2008]   [Aug]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRE: [linux-pm] Power management for SCSI
Date
From
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
hot-plug
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...

marty

> -----Original Message-----
> From: Alan Stern [mailto:stern@rowland.harvard.edu]
> Sent: Wednesday, August 13, 2008 4:39 PM
> To: Leisner, Martin
> Cc: Oliver Neukum; Linux-pm mailing list; kernel list;
teheo@novell.com;
> James.Bottomley@hansenpartnership.com; 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:
> >
> > http://www.gossamer-threads.com/lists/linux/kernel/811598
>
> 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
that
> disk will be lost.
>
> Alan Stern



\
 
 \ /
  Last update: 2008-08-19 23:13    [W:0.045 / U:7.240 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site