From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756419AbYAGPjW (ORCPT ); Mon, 7 Jan 2008 10:39:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754041AbYAGPjO (ORCPT ); Mon, 7 Jan 2008 10:39:14 -0500 Received: from iolanthe.rowland.org ([192.131.102.54]:36539 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753120AbYAGPjO (ORCPT ); Mon, 7 Jan 2008 10:39:14 -0500 Date: Mon, 7 Jan 2008 10:39:13 -0500 (EST) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Pavel Machek cc: Oliver Neukum , Raymano Garibaldi , Andrew Morton , Denys Vlasenko , Kernel development list , USB development list Subject: Re: [linux-usb-devel] [FEATURE REQUEST] Transparent hot plugging of root file system on portable storage devices. In-Reply-To: <20080106224429.GA1664@elf.ucw.cz> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 6 Jan 2008, Pavel Machek wrote: > On Sun 2008-01-06 17:26:17, Alan Stern wrote: > > On Sun, 6 Jan 2008, Oliver Neukum wrote: > > > > > Am Sonntag 06 Januar 2008 schrieb Alan Stern: > > > > What about people who want to suspend to RAM instead of hibernating and > > > > _do_ want to unplug the USB device containing their root filesystem > > > > while the machine is asleep? > > Ok, I guess I'm lost here. That sounds like a nice way to do > self-leg-shooting. Are there such people? Yes. People with small systems having extremely limited rw storage (no swap space), using removable read-only media as their root fs. You can find the thread leading up to this request here: http://marc.info/?t=119544588400002&r=1&w=2 > > > Would it be hard to force the persist feature on for a replugged device? > > > > Right now the persist feature is enabled by a per-device boolean flag. > > In theory the flag could accept 3 values: off, on if power was lost, > > or on for any resume transition. This would not be a hard change. > > But do we need it? That depends on whom you ask! :-) > Did you progress on "usb-storage-autosuspend"? Yes; the first round of patches will be posted later today. > Here are my hacks to try to get SATA to survive autosuspend; > unfortunately they do not work :-(. You should start off with minimal support for manual runtime suspend (through a sysfs attribute). When that's working, autosuspend will be easier to add in. Alan Stern