USB: EHCI: improvements to unlink_empty_async_suspended()

unlink_empty_async_suspended() is marked __maybe_unused.  This is
because its caller, ehci_bus_suspend(), is protected by "#ifdef
CONFIG_PM".  We should use the same protection here instead of
__maybe_unused.

unlink_empty_async_suspended() gets called only when the root hub is
suspended.  It's silly for it to call start_iaa_cycle() at such a
time; the IAA mechanism doesn't work when the root hub isn't running.
It should call end_unlink_async() instead.  But even this isn't
necessary, since there already is a call to end_iaa_cycle() right
before the call to unlink_empty_async_suspended().  All we have to do
is interchange the two subroutine calls.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-hub.c

@@ -347,9 +347,10 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
 		goto done;
 	ehci->rh_state = EHCI_RH_SUSPENDED;
 
+	unlink_empty_async_suspended(ehci);
+
 	/* Any IAA cycle that started before the suspend is now invalid */
 	end_iaa_cycle(ehci);
-	unlink_empty_async_suspended(ehci);
 	ehci_handle_start_intr_unlinks(ehci);
 	ehci_handle_intr_unlinks(ehci);
 	end_free_itds(ehci);

drivers/usb/host/ehci-q.c

@@ -1459,8 +1459,10 @@ static void unlink_empty_async(struct ehci_hcd *ehci)
 	}
 }
 
+#ifdef	CONFIG_PM
+
 /* The root hub is suspended; unlink all the async QHs */
-static void __maybe_unused unlink_empty_async_suspended(struct ehci_hcd *ehci)
+static void unlink_empty_async_suspended(struct ehci_hcd *ehci)
 {
 	struct ehci_qh		*qh;
 
@@ -1469,9 +1471,10 @@ static void __maybe_unused unlink_empty_async_suspended(struct ehci_hcd *ehci)
 		WARN_ON(!list_empty(&qh->qtd_list));
 		single_unlink_async(ehci, qh);
 	}
-	start_iaa_cycle(ehci);
 }
 
+#endif
+
 /* makes sure the async qh will become idle */
 /* caller must own ehci->lock */