From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH] sd: implement stop_on_shutdown Date: Sat, 20 Jan 2007 12:22:10 +0900 Message-ID: <45B18AE2.3010503@gmail.com> References: <20070119170122.GS10987@htj.dyndns.org> <45B1574D.1090502@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <45B1574D.1090502@us.ibm.com> Sender: linux-scsi-owner@vger.kernel.org To: "Darrick J. Wong" Cc: James.Bottomley@SteelEye.com, Jeff Garzik , hmh@hmh.eng.br, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org List-Id: linux-ide@vger.kernel.org Darrick J. Wong wrote: > Tejun Heo wrote: >> sd doesn't stop (unload head) on shutdown. This behavior is necessary >> for multi initiator cases. Unloading head by powering off stresses >> the drive and sometimes produces distinct clunking noise which >> apparently disturbs users considering multiple reports on different >> distributions. halt(8) usually puts the drives to sleep prior to >> shutdown but the implementation is fragile and it doesn't work with >> sleep-to-disk. > > I wonder if this sort of thing (cache flush + spin down) is the sort of > thing that ought to be done to near-line storage at suspend time too, > though one would want allow_restart = 1 before doing such a thing. For ATA, it's currently being done inside libata proper (a bit ugly). It would be nice to have those implemented at sd layer but I wonder how useful it's going to be for actual SCSI devices. Do people actually suspend using SCSI? If it's useful at the SCSI layer, I can implement and test it with SATA devices here. Thanks. -- tejun