Re: Power management for SCSI

[Stefan Richter <stefanr@s5r6.in-berlin.de>]

Pavel Machek wrote:
>> https://lists.linux-foundation.org/pipermail/linux-pm/2008-March/016849.html
...
> First the general comments/questions:
> 
> #
> #1. It's done at the wrong level: suspend "device" is actually a target
> #function.  There's no way on a multi-lun device we want to keep the
> #flags and last_busy anywhere but in the target
> 
> So... if there's one device with Lun0==cdrom1 and Lun1==cdrom2, it is a
> single target, and we want to keep flags/last busy common to all that?

Actually a command set driver like sd surely wants last_busy (time of 
last use) separate for each LU for auto-spindown, doesn't it?

I'm not sure about the rest, i.e. delay, counter, flags.

> What is good data structure to add? I see scsi_tgt*.h, but it is very
> short, and there does not seem to be good structure to hook into.

include/scsi/scsi_tgt*.h are for local target implementations.  The 
representation of "remote" targets, as seen by local initiators, is 
include/scsi/scsi_device.h's struct scsi_target.
-- 
Stefan Richter
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http://arcgraph.de/sr/