From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265086AbUELAlr (ORCPT ); Tue, 11 May 2004 20:41:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265080AbUELAlq (ORCPT ); Tue, 11 May 2004 20:41:46 -0400 Received: from gateway-1237.mvista.com ([12.44.186.158]:21756 "EHLO av.mvista.com") by vger.kernel.org with ESMTP id S265086AbUELAjw (ORCPT ); Tue, 11 May 2004 20:39:52 -0400 Message-ID: <40A17251.2000500@mvista.com> Date: Tue, 11 May 2004 17:39:45 -0700 From: Todd Poynor User-Agent: Mozilla Thunderbird 0.6 (X11/20040502) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Greg KH CC: mochel@digitalimplant.org, linux-hotplug-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: Hotplug events for system suspend/resume References: <20040511010015.GA21831@dhcp193.mvista.com> <20040511230001.GA26569@kroah.com> In-Reply-To: <20040511230001.GA26569@kroah.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Greg KH wrote: > I still do not see the need for this. As a user, you caused the > suspend/resume event to happen, why get notified of it again? :) The idea is to notify the "power management application" of impending suspend and just-completed resume, regardless of who or what asked for the suspend. Actions taken at suspend might include dropping network connections and saving application state to stable storage. The reasons for which this was requested of me as a kernel-to-userspace notifier, that I am aware of, are: (a) some embedded platforms currently trigger suspend within kernel drivers (in response to a button press or some sort of device timeout). (b) the system designer wants to make sure certain actions are always taken regardless of the interface used to suspend (not only in the case of a certain application that incorporates these actions and triggers the suspend via the standard interfaces at the appropriate time). For example, a user manually enters a command from a shell prompt. But again, I'll let the embedded system designers jump in here if they'd like to add some insight. In both of the above cases, some ad-hoc method of kernel-to-userspace notification could be used, but I am trying to gauge interest in using hotplug as a generic notifier for these. Thanks -- Todd