From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Neukum Subject: Re: question on flushing buffers and spinning down disk Date: Tue, 18 Sep 2007 16:15:46 +0200 Message-ID: <200709181615.46537.oliver@neukum.org> References: <200709181032.29864.oliver@neukum.org> <1190124061.3375.5.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from smtp-out002.kontent.com ([81.88.40.216]:60594 "EHLO smtp-out.kontent.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753416AbXIROPQ (ORCPT ); Tue, 18 Sep 2007 10:15:16 -0400 In-Reply-To: <1190124061.3375.5.camel@localhost.localdomain> Content-Disposition: inline Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: linux-scsi@vger.kernel.org Am Dienstag 18 September 2007 schrieb James Bottomley: > On Tue, 2007-09-18 at 10:32 +0200, Oliver Neukum wrote: > > which function should a lldd call to make the scsi layer flush > > a device's buffers and spin it down? Which kind of locking is > > required? > > Depends on the context. Is this for suspend? If so it's done > automatically by the sd driver, but the device has to be marked for it > in the manage_start_stop attributes. It is for runtime power management. We've gotten a bug report about a drive enclosure that doesn't properly park heads if the usb device is simply suspended. Apparently it simply cuts power so the cache can be lost, too. Regards Oliver