From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King Subject: Re: [PATCH/RFC] PCI prepare/activate instead of enable to avoid IRQ storm and rogue DMA access Date: Wed, 14 Mar 2007 22:58:18 +0000 Message-ID: <20070314225818.GB7194@flint.arm.linux.org.uk> References: <20070314152302.GB15600@htj.dyndns.org> <20070314215605.GA7194@flint.arm.linux.org.uk> <45F87863.9040408@garzik.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <45F87863.9040408@garzik.org> Sender: linux-ide-owner@vger.kernel.org To: Jeff Garzik Cc: Tejun Heo , gregkh@suse.de, linux-kernel@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz, michal.k.k.piotrowski@gmail.com, linux-ide@vger.kernel.org, tglx@linutronix.de, shemminger@linux-foundation.org, mlord@pobox.com, linux-pm@lists.osdl.org List-Id: linux-pm@vger.kernel.org On Wed, Mar 14, 2007 at 06:34:11PM -0400, Jeff Garzik wrote: > Russell King wrote: > >pci_enable_device() doesn't deal with this; in most PCI setups I've > >seen, there is no control at PCI level over whether a device generates > >an interrupt on the bus. Certainly the memory and io command enables > > PCI grew an interrupt enable while you weren't looking: > PCI_COMMAND_INTX_DISABLE That's fine for devices which conform to the later PCI specs, but not all do. > It was added in PCI 2.3 I think. Correct. > Older PCI devices certainly do not have this standardized bit. No PCI device that I have has that bit - including the raid card I bought last year... In any case, relying on such a new control bit to implement this kind of functionality would result in a very hit and miss result; Linux tends to get used on things other than the bleeding edge of hardware technology. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: