Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932515Ab2FGRg4 (ORCPT ); Thu, 7 Jun 2012 13:36:56 -0400 Received: from g4t0017.houston.hp.com ([15.201.24.20]:21193 "EHLO g4t0017.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759742Ab2FGRgy (ORCPT ); Thu, 7 Jun 2012 13:36:54 -0400 Subject: Re: [PATCH] Disable Bus Master on PCI device shutdown From: Khalid Aziz To: Andi Kleen Cc: Alan Cox , Matthew Garrett , linux-kernel@vger.kernel.org, bhelgaas@google.com, linux-pci@vger.kernel.org In-Reply-To: References: <20120427190033.GA17588@ldl.usa.hp.com> <20120606135009.GB1517@srcf.ucam.org> <20120606215034.257d7549@pyramind.ukuu.org.uk> Content-Type: text/plain; charset="UTF-8" Date: Thu, 07 Jun 2012 11:36:53 -0600 Message-ID: <1339090613.25761.888.camel@lyra> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1430 Lines: 38 On Thu, 2012-06-07 at 10:07 -0700, Andi Kleen wrote: > Alan Cox writes: > > >> This protects against the case where a piece of hardware is continuing > >> to DMA even after the driver shutdown method has been called? I'm not > > > > It doesn't. We also have hardware which craps itself if you clear the bus > > mastering bit and we have platforms where the BIOS gets most upset if you > > do that on suspend paths. There are also lots of devices that simply > > ignore the bus mastering bit ! > > But it also makes my system do kexec successfully for the first time. > > Maybe can make it an option. > > n-Andi > Hi Andi, That makes my day :) It will be very helpful to see which PCI devices your system has. I was thinking about kernel command line option this morning and had started looking at reset_devices option to see if I could leverage that one in any way. -- ==================================================================== Khalid Aziz Unix Systems Lab (970)898-9214 Hewlett-Packard khalid.aziz@hp.com Fort Collins, CO -- 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/