From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261296AbUDBXOP (ORCPT ); Fri, 2 Apr 2004 18:14:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261298AbUDBXOP (ORCPT ); Fri, 2 Apr 2004 18:14:15 -0500 Received: from gateway-1237.mvista.com ([12.44.186.158]:10232 "EHLO av.mvista.com") by vger.kernel.org with ESMTP id S261296AbUDBXOO (ORCPT ); Fri, 2 Apr 2004 18:14:14 -0500 Message-ID: <406DF3B0.4030300@mvista.com> Date: Fri, 02 Apr 2004 15:13:52 -0800 From: Todd Poynor User-Agent: Mozilla Thunderbird 0.5 (X11/20040208) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Patrick Mochel CC: linux-kernel@vger.kernel.org Subject: Re: [PATCH] Device suspend/resume fixes References: <20040402222838.GB2423@dhcp193.mvista.com> In-Reply-To: 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 Patrick Mochel wrote: >>(3) Flush signals between resume handlers in case a resume function >>causes, for example, an ECHILD from modprobe or hotplug, so >>interruptible APIs for the next handler aren't affected. > > > Are there really cases in which you see this as an issue? Ugh, I meant SIGCHILD, not ECHILD. We have seen this in the past on a 2.4 backport, although perhaps in a different environment than is normally used (this was on a PowerPC embedded platform that powers off the I/O ring during suspend). For certain hotpluggable devices such as USB we've found it best to completely de-init and re-init the controller and re-sense plugged cards at suspend/resume time, which is when we saw troublesome signals (I2C setup then "timed out" before the controller was ready because a SIGCHILD was waiting). I admit I don't know that much about the hotplug handlers, maybe I just didn't have things setup properly. So if this seems bizarre then I'll withdraw it and try things again later when I have such hardware running in 2.6. Thanks, -- Todd Poynor MontaVista Software