Re: [PATCH/RFC] PCI prepare/activate instead of enable to avoid IRQ storm and rogue DMA access

Jeff Garzik
2007-03-14T22:34:11Z

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

No idea about ARM, but almost all PCI devices made in the past few years
support that bit.

Unless you are using a PCI Express device (maybe PCI-X too?), though,
you cannot count on the bit's presence. It was added in PCI 2.3 I
think. Older PCI devices certainly do not have this standardized bit.

Jeff