Re: Power management for SCSI

[Alan Stern]

On Wed, 13 Aug 2008, Stefan Richter wrote:

> > For transports which are like USB, we should do autosuspend at the
> > target (not device) level.  This means invoking the suspend/resume 
> > routines of the ULDs like sd and sr.  The transport gets notified when 
> > all of the targets are suspended.  (Or maybe the host driver gets 
> > notified instead; there probably isn't any advantage to using the 
> > transport class here.)
> > 
> > For other transports, we should only do idle-timeout detection.  The
> > transport gets notified when any target has been idle for sufficiently 
> > long, so that it can power down the link.  The ULDs are not involved.
> > 
> > Does that sound okay?
> 
> Minor correction:  The ULD suspend/resume methods necessarily work on
> logical units, not targets.

Yes; I should said that the suspend/resume methods of the ULD for each 
of the target's LUNs gets invoked.

Alan Stern

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