From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Richter Subject: Re: Power management for SCSI Date: Wed, 13 Aug 2008 17:44:00 +0200 Message-ID: <48A30140.9040704@s5r6.in-berlin.de> References: <200808131724.52461.oneukum@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200808131724.52461.oneukum@suse.de> Sender: linux-kernel-owner@vger.kernel.org To: Oliver Neukum Cc: Alan Stern , Pavel Machek , kernel list , Linux-pm mailing list , James.Bottomley@hansenpartnership.com, teheo@novell.com List-Id: linux-pm@vger.kernel.org Oliver Neukum wrote: > Am Mittwoch 13 August 2008 16:59:23 schrieb Alan Stern: [Quoting Oliver: true SCSI busses can be shared. So are we using the correct approach?] >> This is a good question. Most USB mass-storage devices do not act as a >> true SCSI bus, but I believe there are a few non-standard ones that do >> -- the USB device really contains a SCSI host and arbitrary SCSI > > OK, but does it make sense to have SCSI autosuspend? Or should autosuspend > operate on the bus the _host_ is connected to (usb, pci, ...)? In Alan's patch, SCSI calls scsi_host_template methods (if the LLD provides ones) to suspend and resume a Scsi_Host. The LLD can use them to work with the underlying infrastructure to determine what can be done at that time. I.e. are there other protocols or other initiator-like nodes sharing the link? If yes or if "maybe yes", the infrastructure keeps the link up. If not, it can move it into a low-power state. -- Stefan Richter -=====-==--- =--- -==-= http://arcgraph.de/sr/