USB: OHCI: fix root-hub resume bug

When a suspended OHCI controller sees a port's status change, it sets
both the Root-Hub-Status-Change and the Resume-Detect bits in the
Interrupt Status register.  Processing both these bits, the driver
tries to resume the root hub twice!

This patch (as807) fixes the bug by ignoring RD if RHSC is set.  It
also prints a slightly more informative log message when a
remote-wakeup event occurs.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/ohci-hcd.c

@@ -715,13 +715,6 @@ static irqreturn_t ohci_irq (struct usb_hcd *hcd)
 		return IRQ_NOTMINE;
 	}
 
-	if (ints & OHCI_INTR_RHSC) {
-		ohci_vdbg (ohci, "rhsc\n");
-		ohci->next_statechange = jiffies + STATECHANGE_DELAY;
-		ohci_writel (ohci, OHCI_INTR_RHSC, &regs->intrstatus);
-		usb_hcd_poll_rh_status(hcd);
-	}
-
 	if (ints & OHCI_INTR_UE) {
 		disable (ohci);
 		ohci_err (ohci, "OHCI Unrecoverable Error, disabled\n");
@@ -731,9 +724,21 @@ static irqreturn_t ohci_irq (struct usb_hcd *hcd)
 		ohci_usb_reset (ohci);
 	}
 
-	if (ints & OHCI_INTR_RD) {
-		ohci_vdbg (ohci, "resume detect\n");
-		ohci_writel (ohci, OHCI_INTR_RD, &regs->intrstatus);
+	if (ints & OHCI_INTR_RHSC) {
+		ohci_vdbg(ohci, "rhsc\n");
+		ohci->next_statechange = jiffies + STATECHANGE_DELAY;
+		ohci_writel(ohci, OHCI_INTR_RD | OHCI_INTR_RHSC,
+				&regs->intrstatus);
+		usb_hcd_poll_rh_status(hcd);
+	}
+
+	/* For connect and disconnect events, we expect the controller
+	 * to turn on RHSC along with RD.  But for remote wakeup events
+	 * this might not happen.
+	 */
+	else if (ints & OHCI_INTR_RD) {
+		ohci_vdbg(ohci, "resume detect\n");
+		ohci_writel(ohci, OHCI_INTR_RD, &regs->intrstatus);
 		hcd->poll_rh = 1;
 		if (ohci->autostop) {
 			spin_lock (&ohci->lock);

drivers/usb/host/ohci-hub.c

@@ -169,7 +169,8 @@ __acquires(ohci->lock)
 		break;
 	case OHCI_USB_RESUME:
 		/* HCFS changes sometime after INTR_RD */
-		ohci_info (ohci, "wakeup\n");
+		ohci_info(ohci, "%swakeup\n",
+				autostopped ? "auto-" : "");
 		break;
 	case OHCI_USB_OPER:
 		/* this can happen after resuming a swsusp snapshot */