Re: 3.4.4: disabling irq

[Alan Stern]

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

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