From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Neukum Subject: Re: question on flushing buffers and spinning down disk Date: Mon, 24 Sep 2007 17:21:50 +0200 Message-ID: <200709241721.50887.oliver@neukum.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from smtp-out002.kontent.com ([81.88.40.216]:44392 "EHLO smtp-out.kontent.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752701AbXIXPU6 (ORCPT ); Mon, 24 Sep 2007 11:20:58 -0400 In-Reply-To: Content-Disposition: inline Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Alan Stern Cc: James Bottomley , linux-usb-devel@lists.sourceforge.net, linux-scsi@vger.kernel.org Am Montag 24 September 2007 schrieb Alan Stern: > On Mon, 24 Sep 2007, Oliver Neukum wrote: > > > Am Dienstag 18 September 2007 schrieb James Bottomley: > > > On Tue, 2007-09-18 at 16:15 +0200, Oliver Neukum wrote: > > > > > 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. > > > > > > But even for runtime, if you want to suspend the device, shouldn't you > > > be calling the suspend methods in the device tree? > > > > Very good question. It seems to that yes indeed, we should. But we don't > > in case of autosuspend. We simply suspend the interfaces: > > It's a loaded question. The fact is, the existing suspend methods in > the device tree are intended for system-wide suspend, not for runtime Unfortunately true. > suspend. The PM and driver cores don't include _any_ provision for > runtime suspend; it has to be managed separately by each subsystem. There we have a problem. We'd have to solve it for each subsystem transition. Storage has this type of children, other devices will have to care for other types of child devices. If we have a device tree, we should use it. Regards Oliver