usb hub:

	- fix problem with us not delaying for any ammount of time after a new device
	  has been powered up, as the USB spec indicates should happen.

diff --git a/drivers/usb/hub.c b/drivers/usb/hub.c
index bc89ba9701639d3f2d77964fec7cbec584c970fa..91bdb634558725188c696c21edcd4656469ad328 100644 (file)
--- a/drivers/usb/hub.c
+++ b/drivers/usb/hub.c
@@ -644,6 +644,49 @@ void usb_hub_port_disable(struct usb_device *hub, int port)
                        port + 1, hub->devpath, ret);
 }
 
+/* USB 2.0 spec, 7.1.7.3 / fig 7-29:
+ *
+ * Between connect detection and reset signaling there must be a delay
+ * of 100ms at least for debounce and power-settling. The corresponding
+ * timer shall restart whenever the downstream port detects a disconnect.
+ * 
+ * Apparently there are some bluetooth and irda-dongles and a number
+ * of low-speed devices which require longer delays of about 200-400ms.
+ * Not covered by the spec - but easy to deal with.
+ *
+ * This implementation uses 400ms minimum debounce timeout and checks
+ * every 10ms for transient disconnects to restart the delay.
+ */
+
+#define HUB_DEBOUNCE_TIMEOUT   400
+#define HUB_DEBOUNCE_STEP      10
+
+/* return: -1 on error, 0 on success, 1 on disconnect.  */
+static int usb_hub_port_debounce(struct usb_device *hub, int port)
+{
+       int ret;
+       unsigned delay_time;
+       u16 portchange, portstatus;
+
+       for (delay_time = 0; delay_time < HUB_DEBOUNCE_TIMEOUT; /* empty */ ) {
+
+               /* wait debounce step increment */
+               wait_ms(HUB_DEBOUNCE_STEP);
+
+               ret = usb_hub_port_status(hub, port, &portstatus, &portchange);
+               if (ret < 0)
+                       return -1;
+
+               if ((portchange & USB_PORT_STAT_C_CONNECTION)) {
+                       usb_clear_port_feature(hub, port+1, USB_PORT_FEAT_C_CONNECTION);
+                       delay_time = 0;
+               }
+               else
+                       delay_time += HUB_DEBOUNCE_STEP;
+       }
+       return ((portstatus&USB_PORT_STAT_CONNECTION)) ? 0 : 1;
+}
+
 static void usb_hub_port_connect_change(struct usb_hub *hubstate, int port,
                                        u16 portstatus, u16 portchange)
 {
@@ -671,12 +714,16 @@ static void usb_hub_port_connect_change(struct usb_hub *hubstate, int port,
                return;
        }
 
+       if (usb_hub_port_debounce(hub, port)) {
+               err("connect-debounce failed, port %d disabled", port+1);
+               usb_hub_port_disable(hub, port);
+               return;
+       }
+
        /* Some low speed devices have problems with the quick delay, so */
        /*  be a bit pessimistic with those devices. RHbug #23670 */
-       if (portstatus & USB_PORT_STAT_LOW_SPEED) {
-               wait_ms(400);
+       if (portstatus & USB_PORT_STAT_LOW_SPEED)
                delay = HUB_LONG_RESET_TIME;
-       }
 
        down(&usb_address0_sem);