Re: [PATCH V2 05/10] USB: OHCI: Properly handle ohci-exynos suspend

On Tue, 18 Jun 2013, Manjunath Goudar wrote:

After Alan explanation I am writing below code end of ohci_suspend() routine.is it correct Alan.

   if (do_wakeup && HCD_WAKEUP_PENDING(hcd)) {
            ohci_resume(hcd, false);
            rc = -EBUSY;
    }

I'm glad you asked, because there is an important part I forgot about. Just before the code above, it is also necessary to add:

synchronize_irq(hcd->irq);

The reason is because a wakeup interrupt might race with the suspend call. If the suspend finishes first, we need to wait until the interrupt has been handled before checking whether there is a pending wakeup. That's what synchronize_irq() does; it waits until all the outstanding interrupt requests have been handled.

(Also, as Sachin pointed out, you have to return rc instead of 0.)

Alan Stern