Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261424AbVDZQkx (ORCPT ); Tue, 26 Apr 2005 12:40:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261696AbVDZQgU (ORCPT ); Tue, 26 Apr 2005 12:36:20 -0400 Received: from colo.lackof.org ([198.49.126.79]:9948 "EHLO colo.lackof.org") by vger.kernel.org with ESMTP id S261678AbVDZQfC (ORCPT ); Tue, 26 Apr 2005 12:35:02 -0400 Date: Tue, 26 Apr 2005 10:37:34 -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: <20050426163734.GF2612@colo.lackof.org> References: <20050426154942.GB2612@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: 1284 Lines: 25 On Tue, Apr 26, 2005 at 12:04:00PM -0400, Alan Stern wrote: > > Sure there is. Every IRQ line goes to an IRQ controller. > > Arch specific code deals with programming the controller and can > > mask all interrupts (or not). Historically, they've been left unmasked > > for ISA IRQ discovery and debugging misrouted IRQ lines. > > This doesn't help. Consider what happens when two devices share an IRQ > line. Suppose device B is generating interrupt requests when the driver > for device A is probed. The driver registers its handler, which causes > the IRQ line to be unmasked. Then a multitude of IRQs arrive from B, none > of which can be handled by A's driver. So the kernel shuts the IRQ line > down permanently... 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? 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/