The disable state isn't tracked at the moment, instead the state is
directly passed to the hub driver. Change this behavior to only trigger
the hub if a state change happened. Exit early in case of no state
changes but don't return an error.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
---
 drivers/usb/core/hub.h  | 2 ++
 drivers/usb/core/port.c | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
index 9ebc5ef54a325d63e01b0deb59a1853d2b13c8d5..297adf2c6078809ca582104f228e5222c464f999 100644
--- a/drivers/usb/core/hub.h
+++ b/drivers/usb/core/hub.h
@@ -97,6 +97,7 @@ struct usb_hub {
  * @usb3_lpm_u2_permit: whether USB3 U2 LPM is permitted.
  * @early_stop: whether port initialization will be stopped earlier.
  * @ignore_event: whether events of the port are ignored.
+ * @disabled: whether the port is disabled
  */
 struct usb_port {
 	struct usb_device *child;
@@ -118,6 +119,7 @@ struct usb_port {
 	unsigned int is_superspeed:1;
 	unsigned int usb3_lpm_u1_permit:1;
 	unsigned int usb3_lpm_u2_permit:1;
+	unsigned int disabled:1;
 };
 
 #define to_usb_port(_dev) \
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index f54198171b6a3fb49c5f74f4a8a303b422d099eb..cae08a9a71e65c42fb9a8f5369060bd82b8daebb 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -117,6 +117,10 @@ static ssize_t disable_store(struct device *dev, struct device_attribute *attr,
 	if (rc)
 		return rc;
 
+	/* Early quit if no change was detected */
+	if (port_dev->disabled == disabled)
+		return count;
+
 	hub_get(hub);
 	rc = usb_autopm_get_interface(intf);
 	if (rc < 0)
@@ -148,6 +152,8 @@ static ssize_t disable_store(struct device *dev, struct device_attribute *attr,
 			usb_clear_port_feature(hdev, port1, USB_PORT_FEAT_C_ENABLE);
 	}
 
+	port_dev->disabled = disabled;
+
 	if (!rc)
 		rc = count;
 

-- 
2.47.3