From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755857Ab0ERBEs (ORCPT ); Mon, 17 May 2010 21:04:48 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:41089 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753255Ab0ERBEr (ORCPT ); Mon, 17 May 2010 21:04:47 -0400 Date: Mon, 17 May 2010 18:02:10 -0700 (PDT) From: Linus Torvalds To: Robert Hancock cc: Andreas Herrmann , Yuhong Bao , venkatesh.pallipadi@intel.com, markh@compro.net, dmarkh@cfl.rr.com, andi@firstfloor.org, alain@knaff.lu, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86: Disable HPET MSI on ATI SB700/SB800 In-Reply-To: <4BF1E5BE.9010000@gmail.com> Message-ID: References: <87bphpd4rt.fsf@basil.nowhere.org> <4B32565E.6000501@compro.net> <20091223191806.GA3336@linux-os.sc.intel.com> <4B3270FE.5090607@compro.net> <1261600243.16916.56.camel@localhost.localdomain> <4B476E8D.1030308@compro.net> <20100121190952.GA32523@linux-os.sc.intel.com> <20100125171059.GB5041@alberich.amd.com> <20100517145943.GV5888@alberich.amd.com> <4BF1E5BE.9010000@gmail.com> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 17 May 2010, Robert Hancock wrote: > > If one wanted, you could disable HPET MSI on this chipset only when a driver > requests an ISA DMA channel. Then if there's no floppy or other LPC DMA device > present, it can stay enabled. I don't know if it's worth the trouble, though. Nope, that wouldn't work. Imagine a driver that already loaded, and is already using MSI (say, network device). What happens now if you want to access the floppy and load the floppy module? Oh, you can't? Need to bring down the network interface, unload that module first? Not practical. Sure, in theory we can do some crazy callback for "you now need to re-do your interrupt registration" for all devices. In practice, I can onyl say "not going to happen". Linus