@@ -888,6 +888,7 @@ static irqreturn_t ohci_irq (struct usb_hcd *hcd)
/* Check for an all 1's result which is a typical consequence
* of dead, unclocked, or unplugged (CardBus...) devices
*/
+again:
if (ints == ~(u32)0) {
ohci->rh_state = OHCI_RH_HALTED;
ohci_dbg (ohci, "device removed!\n");
@@ -982,6 +983,13 @@ static irqreturn_t ohci_irq (struct usb_hcd *hcd)
}
spin_unlock(&ohci->lock);
+ /* repeat until all enabled interrupts are handled */
+ if (ohci->rh_state != OHCI_RH_HALTED) {
+ ints = ohci_readl(ohci, ®s->intrstatus);
+ if (ints && (ints & ohci_readl(ohci, ®s->intrenable)))
+ goto again;
+ }
+
return IRQ_HANDLED;
}
Testing ohci functionality with qemu's pci-ohci emulation often results in ohci interface stalls, resulting in hung task timeouts. The problem is caused by lost interrupts between the emulation and the Linux kernel code. Additional interrupts raised while the ohci interrupt handler in Linux is running and before the handler clears the interrupt status are not handled. The fix for a similar problem in ehci suggests that the problem is likely caused by edge-triggered MSI interrupts. See commit 0b60557230ad ("usb: ehci: Prevent missed ehci interrupts with edge-triggered MSI") for details. Ensure that the ohci interrupt code handles all pending interrupts before returning to solve the problem. Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: David Laight <David.Laight@aculab.com> Cc: stable@vger.kernel.org Fixes: 306c54d0edb6 ("usb: hcd: Try MSI interrupts on PCI devices") Signed-off-by: Guenter Roeck <linux@roeck-us.net> --- v3: Check if any interrupts are pending before reading intrenable Add 'Cc: stable@vger.kernel.org' v2: Only repeat if the interface is still active Note that I did not apply Alan's Reviewed-by: tag since I was not sure if that was appropriate after the code change. drivers/usb/host/ohci-hcd.c | 8 ++++++++ 1 file changed, 8 insertions(+)