From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH] sd: implement stop_on_shutdown Date: Sat, 20 Jan 2007 04:50:11 -0500 Message-ID: <45B1E5D3.90101@pobox.com> References: <20070119170122.GS10987@htj.dyndns.org> <45B1574D.1090502@us.ibm.com> <45B18AE2.3010503@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <45B18AE2.3010503@gmail.com> Sender: linux-scsi-owner@vger.kernel.org To: Tejun Heo Cc: "Darrick J. Wong" , James.Bottomley@SteelEye.com, hmh@hmh.eng.br, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org List-Id: linux-ide@vger.kernel.org Tejun Heo wrote: > 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. There is always the open question for multi-initiator SCSI devices, as to who "owns" the SCSI device. Some devices should be suspended/stopped when the machine is suspended/stopped, others not. Jeff