Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261736AbVDZRkn (ORCPT ); Tue, 26 Apr 2005 13:40:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261505AbVDZRk1 (ORCPT ); Tue, 26 Apr 2005 13:40:27 -0400 Received: from colo.lackof.org ([198.49.126.79]:56540 "EHLO colo.lackof.org") by vger.kernel.org with ESMTP id S261417AbVDZRiq (ORCPT ); Tue, 26 Apr 2005 13:38:46 -0400 Date: Tue, 26 Apr 2005 11:41:16 -0600 From: Grant Grundler To: Alan Stern Cc: Grant Grundler , Alexander Nyberg , Greg KH , Amit Gud , linux-kernel@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz, akpm@osdl.org, jgarzik@pobox.com, cramerj@intel.com, USB development list Subject: Re: [PATCH] PCI: Add pci shutdown ability Message-ID: <20050426174116.GG2612@colo.lackof.org> References: <20050426163734.GF2612@colo.lackof.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Home-Page: http://www.parisc-linux.org/ User-Agent: Mutt/1.5.6+20040907i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1336 Lines: 28 On Tue, Apr 26, 2005 at 01:14:38PM -0400, Alan Stern wrote: > On Tue, 26 Apr 2005, Grant Grundler wrote: > > > Agreed - but this is a different problem than "shutting down IRQs". > > My point was arch specific code knows how to mask all IRQs. > > irq_disable() is expected to work regardless of what state the > > driver is in. On kexec "reboot", kernel drivers can unmask IRQs > > as they normally would during initialization. No? > > One has to be careful when talking about enabling/disable IRQs, because > there are (at least) two choke points: one on the device and one on the > computer's interrupt controller. Masking IRQs takes place on the > controller, but I was talking about stopping interrupt requests at their > source on the device. It's the only way to avoid problems when IRQ lines > are shared. Yes, got it. I wouldn't object if someone said kexec can not support shared IRQs unless both drivers sharing the IRQ implement PCI "suspend" hook (and disable IRQ on the respective devices). We really don't have many options to fix Shared IRQ problems. thanks, grant - 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/