Messages in this thread | | | Date | Wed, 14 Mar 2007 22:58:18 +0000 | From | Russell King <> | Subject | Re: [PATCH/RFC] PCI prepare/activate instead of enable to avoid IRQ storm and rogue DMA access |
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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: - 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/
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