RE: additional debug output for autosuspend in cdc-ether

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On Fri, 30 Oct 2009, Rickard Bellini wrote:

> 
> Hi,
> 
> I can readily recreate this issue with our device within a few hours of
> usage.
> I've seen this issue on kernels 2.6.24 and newer. The one I'm currently
> running
> is 2.6.32-rc3 with the aggressive autosuspend patch for cdc_ether.
> 
> Thank you for spending time on this since it is becoming an issue for
> us.
> Please let me know when you have something you want me to test.

Here's a patch you can try out.  This approach was suggested by the 
guys at Motorola; let's see if it works.

Alan Stern


Index: usb-2.6/drivers/usb/host/ehci-hub.c
===================================================================
--- usb-2.6.orig/drivers/usb/host/ehci-hub.c
+++ usb-2.6/drivers/usb/host/ehci-hub.c
@@ -120,9 +120,26 @@ static int ehci_bus_suspend (struct usb_
 	del_timer_sync(&ehci->watchdog);
 	del_timer_sync(&ehci->iaa_watchdog);
 
-	port = HCS_N_PORTS (ehci->hcs_params);
 	spin_lock_irq (&ehci->lock);
 
+	/* Once the controller is stopped, port resumes that are already
+	 * in progress won't complete.  Hence if remote wakeup is enabled
+	 * for the root hub and any ports are in the middle of a resume or
+	 * remote wakeup, we must fail the suspend.
+	 */
+	if (hcd->self.root_hub->do_remote_wakeup) {
+		port = HCS_N_PORTS(ehci->hcs_params);
+		while (port--) {
+			if (ehci->reset_done[port] != 0) {
+				spin_unlock_irq(&ehci->lock);
+				ehci_dbg(ehci, "suspend failed because "
+						"port %d is resuming\n",
+						port + 1);
+				return -EBUSY;
+			}
+		}
+	}
+
 	/* stop schedules, clean any completed work */
 	if (HC_IS_RUNNING(hcd->state)) {
 		ehci_quiesce (ehci);
@@ -138,6 +155,7 @@ static int ehci_bus_suspend (struct usb_
 	 */
 	ehci->bus_suspended = 0;
 	ehci->owned_ports = 0;
+	port = HCS_N_PORTS(ehci->hcs_params);
 	while (port--) {
 		u32 __iomem	*reg = &ehci->regs->port_status [port];
 		u32		t1 = ehci_readl(ehci, reg) & ~PORT_RWC_BITS;

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