From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Neukum Subject: Re: [linux-pm] Power management for SCSI Date: Thu, 14 Aug 2008 23:43:55 +0200 Message-ID: <200808142343.56505.oneukum@suse.de> References: Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org To: Alan Stern Cc: Pavel Machek , linux-pm@lists.linux-foundation.org, James.Bottomley@hansenpartnership.com, Linux-pm mailing list , kernel list , teheo@novell.com List-Id: linux-pm@vger.kernel.org Am Donnerstag 14 August 2008 17:47:02 schrieb Alan Stern: > > I don't really argue against flushing the caches. But I cannot that= this would > > demand that we should implement autopsuspend for SCSI. It seems lik= e > > overengineering to me. >=20 > Think of it in two parts: idle-timeout detection and autosuspend. =A0 > Presumably you don't object to the idle-timeout detection (which is=20 > needed for powering down links in general), and you don't argue again= st=20 > the cache-flushing part of autosuspend. =A0Taken together, that's abo= ut=20 > 90% of my proposal. =A0So what is the objectionable 10%? The core problem is that you insist on a rigid bottom-to-top flow of autosuspensions. That's good for systems like USB and PCI which are trees for PM purposes. It makes no sense for true busses with equal members on the bus. Regards Oliver