On Tue, 2007-05-29 at 18:39 -0400, Jeff Garzik wrote:

We check for 0xffffffff because that is often how a fault is indicated, 
when the memory location is read during or immediately after hotplug (or 
if the PCI bus is truly faulty).  So for most hardware, you see

tmp = read(irq status)
if (!tmp)
	return irq-none		/* no irq events raised */
if (tmp == 0xffffffff)
	return irq-none		/* hot unplug or h/w fault */

and the method that determines no interrupt handling is needed.

I guess you are right, but then shouldn't the driver be checking for
faults in other parts of the code too? What if a fault/hotplug occurs
immediately after an interrupt, but before a tx?
Thanks,
Gary