On Thu, 3 Mar 2011, Mark Lord wrote: > Okay, dug out a UHCI 1.1 spec, and the indication from there > is that uhci_irq() can return IRQ_HANDLED in some cases where IRQ_NONE > is more appropriate. What cases are those? > Also, it is not masking the "Reserved" bits from the status register. > Presumably most implementations "read zero" for those bits, > but perhaps not all do. Perhaps not, but I've never come across one that does. This essentially amounts to saying that the only reasons a UHCI controller generates an interrupt request are the documented ones. Suppose the driver did mask out the reserved bits and return IRQ_NONE when none of the defined bits were set. An implementation that did set one of the reserved bits would then create an interrupt storm. > Dunno if this is the cause the XT-PIC errors from earlier in this thread though. It seems most unlikely. If the driver had a bug like that, it would have shown up many years ago. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
