On Tue, 16 Oct 2012, Don Zickus wrote: > > I dislike adding an extra test to a hot path, but there doesn't seem to > > be any way around it. Some of the other HCDs may need a similar > > change. > > I understand your concern. I was curious in uhci_irq, I see the following > fragment: > > status = uhci_readw(uhci, USBSTS); > if (!(status & ~USBSTS_HCH)) /* shared interrupt, not mine */ > return IRQ_NONE; > uhci_writew(uhci, status, USBSTS); /* Clear it */ > > Should that be helping in filtering out shared interrupts or not in this > case?
If it did help, your system wouldn't have crashed. :-) What must have happened is that one of the bits in the USBSTS register was set. It didn't cause an IRQ because the USBINTR register was clear, but an IRQ arrived anyway from some other device sharing the IRQ line. Since USBSTS had bits set, the test above did not filter out the interrupt. In other words, even though it really was a shared interrupt it didn't look that way, because the UHCI controller would have generated an interrupt request if it had been allowed to. > I did not get a chance to test the patch yet. Let me know what happens. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
