From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH] ACPI:remove panic in case hardware has changed after S4 Date: Thu, 18 Jul 2013 00:09:16 +0200 Message-ID: <5649055.6Xlqb8sv3m@vostro.rjw.lan> References: <1373888637-20737-1-git-send-email-oliver@neukum.org> <4740878.DpcUBhhgIN@linux-5eaq.site> <1454582.aQCRT2GPRY@skinner.arch.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7Bit Return-path: Received: from hydra.sisk.pl ([212.160.235.94]:47699 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755340Ab3GQV7U (ORCPT ); Wed, 17 Jul 2013 17:59:20 -0400 In-Reply-To: <1454582.aQCRT2GPRY@skinner.arch.suse.de> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Thomas Renninger Cc: Oliver Neukum , Henrique de Moraes Holschuh , lenb@kernel.org, linux-acpi@vger.kernel.org, Joey Lee On Wednesday, July 17, 2013 04:58:34 PM Thomas Renninger wrote: > On Monday, July 15, 2013 05:35:23 PM Oliver Neukum wrote: > > On Monday 15 July 2013 12:06:11 Henrique de Moraes Holschuh wrote: > > > On Mon, 15 Jul 2013, Thomas Renninger wrote: > > > > I would not make it too complicated. > > > > Sticking to the latest Windows version should be enough for this one. > > > > What bad should happen if we still try to resume and fail... > > > > > > Hmm, why was that check added in the first place? > > > > Safety. > > I expect it is there, because it is stated rather clear in the specs. > > > > If it is useless, > > > removing it for good is fine. If it is _not_ useless, we should still do > > > the checking when not operating in windows-8 firmware mode. > > > > Firmware will only be tested against Windows 8 pretty soon. > > We'd end up with a gigantic list of exceptions. > > Joey found an interessting paper about Win8 behavior: > http://bizsupport2.austin.hp.com/bc/docs/support/SupportManual/c03654081/c03654081.pdf > > It looks like Win8 behaves rather different compared to Linux and is providing > "Hybrid Boot" where the user has to end all his apps. They have no big problem > when resume fails as the user will not lose any data or work he had done > before. > > Joey also found the rather hidden acpi_sleep=s4_nohwsig boot option > which helps as well. > So Linux could do: > 1) Invalidate suspend image and reboot (disadvantage: message is gone) > 2) Panic (current behavior) -> above boot param helps > 3) Still try to resume with a "not so offending message" > 4) ? > > 1. seem to be what Win8 is doing > 3. sounds best to me. It could be ugly if suspend fails and > it always worked before and all your work/data is gone. So trying > hard to resume sounds like a good idea We can also blacklist systems that need acpi_sleep=s4_nohwsig due to idiotic hardware/BIOS design choices. In any case, if we remove the panic, we should also drop s4_nohwsig and since we have that (which I forgot about, by bad), the whole issue isn't so urgent, so I'm dropping the patch for the time being. Thanks, Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.