Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753426AbYAPSUm (ORCPT ); Wed, 16 Jan 2008 13:20:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751542AbYAPSUe (ORCPT ); Wed, 16 Jan 2008 13:20:34 -0500 Received: from smtpq2.groni1.gr.home.nl ([213.51.130.201]:55659 "EHLO smtpq2.groni1.gr.home.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751208AbYAPSUe (ORCPT ); Wed, 16 Jan 2008 13:20:34 -0500 Message-ID: <478E4A07.1050803@keyaccess.nl> Date: Wed, 16 Jan 2008 19:16:39 +0100 From: Rene Herman User-Agent: Thunderbird 2.0.0.9 (X11/20071031) MIME-Version: 1.0 To: Bjorn Helgaas CC: Jaroslav Kysela , Andrew Morton , "Rafael J. Wysocki" , Pierre Ossman , Pavel Machek , Ondrej Zary , ALSA development , Linux Kernel , Takashi Iwai , linux-pm@lists.linux-foundation.org Subject: Re: -mm: pnp-do-not-stop-start-devices-in-suspend-resume-path.patch breaks resuming isapnp cards References: <200801092343.48726.linux@rainbow-software.org> <200801141526.57744.bjorn.helgaas@hp.com> <200801161046.05174.bjorn.helgaas@hp.com> In-Reply-To: <200801161046.05174.bjorn.helgaas@hp.com> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -1.0 (-) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2180 Lines: 51 On 16-01-08 18:46, Bjorn Helgaas wrote: > On Tuesday 15 January 2008 12:51:35 am Jaroslav Kysela wrote: >> Ok, something to explain. These flags exists to allow drivers to >> manually configure (override) PnP resources at init time - we know - for >> example in ALSA - that some combinations simply does not work for all >> soundcards. >> >> The DISABLE flags simply tells core PnP layer - driver will handle >> resource allocation itself, don't do anything, just disable hw physically >> and do not change (allocate) any resources. Value 0x03 is valid in this >> semantics. > > It looks like sound drivers use PNP_DRIVER_RES_DISABLE to say "ignore > what PNP tells us about resource usage and we'll just use the compiled- > in or command-line-specified resources". > > The main reason to do that would be to work around BIOS defects or > to work around deficiencies in the Linux PNP infrastructure (e.g., > maybe we erroneously place another device on top of the sound card > or something). > > I'm just suspicious because PNP_DRIVER_RES_DISABLE is only used in > sound drivers. If it's to work around BIOS defects, why wouldn't > other PNP drivers need it sometimes, too? And wouldn't it be better > to use PNP quirks for BIOS workarounds? Yes. The manual resource setting was recently removed from the ALSA drivers and I'd expect this can now go as a package-deal. >> Unfortunately, suspend / resume complicates things a bit, but PnP core can >> handle DO_NOT_CHANGE flag. But it will just mean - _preserve_ resource >> allocation from last suspend state for this device and enable hw >> physically before calling resume() callback. > > When resuming, wouldn't we *always* want to preserve the resource > allocation from the last suspend, regardless of whether > PNP_DRIVER_RES_DO_NOT_CHANGE is specified? Yes. > Linux PNP definitely has issues with suspend/resume, and I suspect > this is one of them. Rene. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/