Re: 3.4.4: disabling irq

Alan Stern
2012-11-19T16:41:35Z

On Sat, 17 Nov 2012, Udo van den Heuvel wrote:

> The problem still happens. irq 18 is dsiabled every now and then.
> This time on different, new hardware.
> The motherboard is now a Gigabyte F2A85X-UP4.
> Camera is the same pwc cam.
>
> Recently I removed the USB printer that was attached to the same USB
> controller.
> So probably it is not a hardware issue related to board or printer.
>
> How to proceed next?

Firstly, what does /proc/interrupts say?

Secondly, try building a kernel with the patch below and
CONFIG_USB_DEBUG enabled. Let's see what the dmesg log says when the
problem occurs.

Alan Stern

Index: usb-3.7/drivers/usb/host/ohci-hcd.c
===================================================================
--- usb-3.7.orig/drivers/usb/host/ohci-hcd.c
+++ usb-3.7/drivers/usb/host/ohci-hcd.c
@@ -777,6 +777,7 @@ static irqreturn_t ohci_irq (struct usb_
struct ohci_hcd *ohci = hcd_to_ohci (hcd);
struct ohci_regs __iomem *regs = ohci->regs;
int ints;
+ int i, j;

/* Read interrupt status (and flush pending writes). We ignore the
* optimization of checking the LSB of hcca->done_head; it doesn't
@@ -795,11 +796,15 @@ static irqreturn_t ohci_irq (struct usb_
}

/* We only care about interrupts that are enabled */
- ints &= ohci_readl(ohci, &regs->intrenable);
+ i = ints;
+ j = ohci_readl(ohci, &regs->intrenable);
+ ints &= j;

/* interrupt for some other device? */
- if (ints == 0 || unlikely(ohci->rh_state == OHCI_RH_HALTED))
+ if (ints == 0 || unlikely(ohci->rh_state == OHCI_RH_HALTED)) {
+ ohci_dbg(ohci, "IRQ: %x %x\n", i, j);
return IRQ_NOTMINE;
+ }

if (ints & OHCI_INTR_UE) {
// e.g. due to PCI Master/Target Abort