USB: don't explicitly reenable root-hub status interrupts

This patch (as1069b) changes the way OHCI root-hub status-change
interrupts are enabled.  Currently a special HCD method,
hub_irq_enable(), is called when the hub driver is finished using a
root hub.  This approach turns out to be subject to races, resulting
in unnecessary polling.

The patch does away with the method entirely.  Instead, the driver
automatically enables the RHSC interrupt when no more status changes
are present.  This scheme is safe with controllers using
level-triggered semantics for their interrupt flags.

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

3 files changed, 0 insertions, 20 deletions

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index e68fef5..bf10e9c 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -924,15 +924,6 @@ static int register_root_hub(struct usb_hcd *hcd)
 	return retval;
 }
 
-void usb_enable_root_hub_irq (struct usb_bus *bus)
-{
-	struct usb_hcd *hcd;
-
-	hcd = container_of (bus, struct usb_hcd, self);
-	if (hcd->driver->hub_irq_enable && hcd->state != HC_STATE_HALT)
-		hcd->driver->hub_irq_enable (hcd);
-}
-
 
 /*-------------------------------------------------------------------------*/
 
diff --git a/drivers/usb/core/hcd.h b/drivers/usb/core/hcd.h
index 3ba258e..1e4b81e 100644
--- a/drivers/usb/core/hcd.h
+++ b/drivers/usb/core/hcd.h
@@ -210,8 +210,6 @@ struct hc_driver {
 	int	(*bus_suspend)(struct usb_hcd *);
 	int	(*bus_resume)(struct usb_hcd *);
 	int	(*start_port_reset)(struct usb_hcd *, unsigned port_num);
-	void	(*hub_irq_enable)(struct usb_hcd *);
-		/* Needed only if port-change IRQs are level-triggered */
 
 		/* force handover of high-speed port to full-speed companion */
 	void	(*relinquish_port)(struct usb_hcd *, int);
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 1e23e36..5a338a5 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2001,8 +2001,6 @@ int usb_port_resume(struct usb_device *udev)
 	}
 
 	clear_bit(port1, hub->busy_bits);
-	if (!hub->hdev->parent && !hub->busy_bits[0])
-		usb_enable_root_hub_irq(hub->hdev->bus);
 
 	if (status == 0)
 		status = finish_port_resume(udev);
@@ -2918,11 +2916,6 @@ static void hub_events(void)
 
 		hub->activating = 0;
 
-		/* If this is a root hub, tell the HCD it's okay to
-		 * re-enable port-change interrupts now. */
-		if (!hdev->parent && !hub->busy_bits[0])
-			usb_enable_root_hub_irq(hdev->bus);
-
 loop_autopm:
 		/* Allow autosuspend if we're not going to run again */
 		if (list_empty(&hub->event_list))
@@ -3148,8 +3141,6 @@ int usb_reset_device(struct usb_device *udev)
 			break;
 	}
 	clear_bit(port1, parent_hub->busy_bits);
-	if (!parent_hdev->parent && !parent_hub->busy_bits[0])
-		usb_enable_root_hub_irq(parent_hdev->bus);
 
 	if (ret < 0)
 		goto re_enumerate;