Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759526AbXE0Ups (ORCPT ); Sun, 27 May 2007 16:45:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753693AbXE0Upk (ORCPT ); Sun, 27 May 2007 16:45:40 -0400 Received: from ppsw-4.csi.cam.ac.uk ([131.111.8.134]:54865 "EHLO ppsw-4.csi.cam.ac.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753571AbXE0Upk (ORCPT ); Sun, 27 May 2007 16:45:40 -0400 X-Cam-SpamDetails: Not scanned X-Cam-AntiVirus: No virus found X-Cam-ScannerInfo: http://www.cam.ac.uk/cs/email/scanner/ In-Reply-To: <200705272231.54535.rjw@sisk.pl> References: <200705272229.21263.rjw@sisk.pl> <200705272231.54535.rjw@sisk.pl> Mime-Version: 1.0 (Apple Message framework v752.2) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: <6BD5252F-96CD-49D9-86C7-18115294D913@cam.ac.uk> Cc: pm list , LKML , Matthew Garrett , Nigel Cunningham , Pavel Machek , Alan Stern , Oliver Neukum Content-Transfer-Encoding: 7bit From: Michael-Luke Jones Subject: Re: [RFC][PATCH -mm 3/3] PM: Disable _request_firmware before hibernation/suspend Date: Sun, 27 May 2007 21:45:35 +0100 To: "Rafael J. Wysocki" X-Mailer: Apple Mail (2.752.2) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1600 Lines: 40 On 27 May 2007, at 21:31, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > Use a hibernation and suspend notifier to disable the firmware > requesting > mechanism before a hibernation/suspend and enable it after the > operation. > > Signed-off-by: Rafael J. Wysocki > > drivers/base/firmware_class.c | 36 ++++++++++++++++++++++++++++++ > ++++++ > 1 file changed, 36 insertions(+) I don't like this approach, as I feel that the firmware loading interface should be able to detect if a firmware load request is not being handled, due to absence of userspace / hotplug handler presence. Other circumstances in which this can be a problem is during bootup when request_firmware() calls can be made before userspace is up and init has run (even in the presence of an initramfs). (Slightly OT: A particularly nasty race is when an initramfs userspace is present, but firmware loading cannot occur because init has not run, so proc hasn't been mounted, so a hotplug event handler cannot be registered, despite the fact that the firmware is sitting on the ramdisk mounted correctly...) In short, a more general solution would be preferred, and preferably one which allows firmware loading to *actually* occur once userspace has actually turned up and registered a handler :) Michael-Luke Jones - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/