From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932076AbVHWMxd (ORCPT ); Tue, 23 Aug 2005 08:53:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932159AbVHWMxd (ORCPT ); Tue, 23 Aug 2005 08:53:33 -0400 Received: from [203.171.93.254] ([203.171.93.254]:31702 "EHLO cunningham.myip.net.au") by vger.kernel.org with ESMTP id S932076AbVHWMxc (ORCPT ); Tue, 23 Aug 2005 08:53:32 -0400 Subject: Re: [patch] suspend: update warnings From: Nigel Cunningham Reply-To: ncunningham@cyclades.com To: Pavel Machek Cc: Andrew Morton , Linux Kernel Mailing List In-Reply-To: <20050823125017.GB3664@elf.ucw.cz> References: <20050822081528.GA4418@elf.ucw.cz> <1124753566.5093.8.camel@localhost> <20050823125017.GB3664@elf.ucw.cz> Content-Type: text/plain Organization: Cyclades Message-Id: <1124801595.4602.18.camel@localhost> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6-1mdk Date: Tue, 23 Aug 2005 22:53:16 +1000 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi. On Tue, 2005-08-23 at 22:50, Pavel Machek wrote: > Hi! > > > > + * If you have unsupported (*) devices using DMA, you may have some > > > + * problems. If your disk driver does not support suspend... (IDE does), > > > + * it may cause some problems, too. If you change kernel command line > > > + * between suspend and resume, it may do something wrong. If you change > > > + * your hardware while system is suspended... well, it was not good idea; > > > + * but it wil probably only crash. > > > > The most common driver issues I see involve: > > - USB being built in or as modules that are still loaded while > > suspending (getting better, but not there yet) > > - DRI being used in X where the drivers don't properly support > > suspend/resume (NVidia esp) > > - Firewire > > - CPU Freq (improving too) > > > > It might be good to mention these areas too. > > Well, right; but those 'only' cause system to crash during suspend. I > was talking about really dangerous stuff. > > Both usb and cpufreq seems to work okay here. It depends on what you're using. I believe one of the usb root hub drivers is okay, the others aren't. Similar for cpufreq. USB certainly accounts for a high percentage of the failures I see. > I've added FAQ entry at the end: > > Q: What information is usefull for debugging suspend-to-disk problems? > > A: Well, last messages on the screen are always useful. If something > is broken, it is usually some kernel driver, therefore trying with as > little as possible modules loaded helps a lot. I also prefer people to > suspend from console, preferably without X running. Booting with > init=/bin/bash, then swapon and starting suspend sequence manually > usually does the trick. Then it is good idea to try with latest > vanilla kernel. > > "Known problematic" modules are; be sure to unload them before > suspend: > - DRI being used in X where the drivers don't properly support > suspend/resume (NVidia esp) > - Firewire > - SCSI > > > > Perhaps the 'changing your hardware' could mention that replacing faulty > > hardware may be safe. > > I do not want to encourage people to do that. Yep, its probably safe, > no, I do not want them to know. :> Thanks Nigel -- Evolution. Enumerate the requirements. Consider the interdependencies. Calculate the probabilities.