From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751291AbVHVXdF (ORCPT ); Mon, 22 Aug 2005 19:33:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751309AbVHVXdE (ORCPT ); Mon, 22 Aug 2005 19:33:04 -0400 Received: from b3162.static.pacific.net.au ([203.143.238.98]:56788 "EHLO cunningham.myip.net.au") by vger.kernel.org with ESMTP id S1751303AbVHVXdD (ORCPT ); Mon, 22 Aug 2005 19:33:03 -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: <20050822081528.GA4418@elf.ucw.cz> References: <20050822081528.GA4418@elf.ucw.cz> Content-Type: text/plain Organization: Cyclades Message-Id: <1124753566.5093.8.camel@localhost> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6-1mdk Date: Tue, 23 Aug 2005 09:32:46 +1000 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi. On Mon, 2005-08-22 at 18:15, Pavel Machek wrote: > Update suspend documentation. Warnings were a bit overstated, and did > not point out important stuff. > > --- > commit 790df7223ac29afec81e7201adc879973311f27e > tree 97fa2017f8f5aded0c44cfc75ba4903fbdb7f0a4 > parent 63393fcbf056a6fd68142a49ed4e1258560dce2c > author Mon, 22 Aug 2005 10:13:51 +0200 > committer Mon, 22 Aug 2005 10:13:51 +0200 > > Documentation/power/swsusp.txt | 60 ++++++++++++++++++++++++++++++++-------- > Documentation/power/video.txt | 9 +++++- > 2 files changed, 56 insertions(+), 13 deletions(-) > > diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt > --- a/Documentation/power/swsusp.txt > +++ b/Documentation/power/swsusp.txt > @@ -1,22 +1,20 @@ > -From kernel/suspend.c: > +Some warnings, first. > > * BIG FAT WARNING ********************************************************* > * > - * If you have unsupported (*) devices using DMA... > - * ...say goodbye to your data. > - * > * If you touch anything on disk between suspend and resume... > * ...kiss your data goodbye. > * > - * If your disk driver does not support suspend... (IDE does) > - * ...you'd better find out how to get along > - * without your data. > - * > - * If you change kernel command line between suspend and resume... > - * ...prepare for nasty fsck or worse. > + * If you do resume from initrd after your filesystems are mounted... > + * ...bye bye root partition. > + * [this is actually same case as above] > * > - * If you change your hardware while system is suspended... > - * ...well, it was not good idea. > + * 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. Perhaps the 'changing your hardware' could mention that replacing faulty hardware may be safe. Regards, Nigel > * > * (*) suspend/resume support is needed to make it safe. > -- Evolution. Enumerate the requirements. Consider the interdependencies. Calculate the probabilities.