From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?utf-8?Q?Peter_M=C3=BCnster?= Subject: Re: prevent disk from spinning up at system resume Date: Mon, 23 Mar 2015 15:36:20 +0100 Message-ID: <877fu7hjbv.fsf@roche-blanche.net> References: <871tkfiz8q.fsf@free.fr> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from plane.gmane.org ([80.91.229.3]:43375 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752100AbbCWOgq (ORCPT ); Mon, 23 Mar 2015 10:36:46 -0400 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1Ya3T2-0005eT-Fu for linux-pm@vger.kernel.org; Mon, 23 Mar 2015 15:36:36 +0100 Received: from arennes-651-1-273-185.w2-2.abo.wanadoo.fr ([2.2.240.185]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 23 Mar 2015 15:36:36 +0100 Received: from pmlists by arennes-651-1-273-185.w2-2.abo.wanadoo.fr with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 23 Mar 2015 15:36:36 +0100 Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: linux-pm@vger.kernel.org On Mon, Mar 23 2015, Alan Stern wrote: > Why does the disk need to be mounted if you aren't using it more than > once a week or so? Why not mount it only while it is in use? The workflow would be quite different: normal workflow: - application needs file on sdb - sdb spins up - application can open the file workflow with unmounted sdb: - application needs file on sdb - error message: no such file (or similar) - user sees error message: "oh dear, the file is on sdb..." - superuser needs to "add-single-device" and mount it - user can continue with application > The kernel wakes up _every_ device during system resume, even ones that > were in runtime suspend when the system suspend started. With only a > few exceptions, there is no way around this in the current kernel. Even after "echo 0 >/sys/block/sdb/device/scsi_disk/2:0:0:0/manage_start_stop" ? If there wasn't the "Synchronizing SCSI cache" at system resume, would the disk spin up nevertheless? -- Peter