From: Russell King <rmk+lkml@arm.linux.org.uk>
To: Jeff Garzik <jeff@garzik.org>
Cc: Tejun Heo <htejun@gmail.com>,
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
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 [thread overview]
Message-ID: <20070314225818.GB7194@flint.arm.linux.org.uk> (raw)
In-Reply-To: <45F87863.9040408@garzik.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:
next prev parent reply other threads:[~2007-03-14 22:58 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-14 15:23 [PATCH/RFC] PCI prepare/activate instead of enable to avoid IRQ storm and rogue DMA access Tejun Heo
2007-03-14 17:04 ` Alan Stern
2007-03-14 17:07 ` Stephen Hemminger
2007-03-15 2:37 ` Tejun Heo
2007-03-15 6:45 ` Grant Grundler
2007-03-16 21:21 ` Stephen Hemminger
2007-03-14 21:46 ` Andi Kleen
2007-03-15 2:39 ` Tejun Heo
2007-03-15 10:17 ` Andi Kleen
2007-03-15 11:41 ` Vivek Goyal
2007-03-14 21:56 ` Russell King
2007-03-14 22:34 ` Jeff Garzik
2007-03-14 22:58 ` Russell King [this message]
2007-03-14 23:16 ` Jeff Garzik
2007-03-15 5:47 ` Tejun Heo
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