Re: [patch]ratelimit debounce error messages

Am Dienstag, 27. Februar 2007 17:03 schrieb Alan Stern:

> Oliver, I've noticed in the past that khubd tries too hard to enumerate a
> new connection.  The new scheme and the old scheme are both tried twice,
> and each try has two attempts to read the device descriptor, where each 
> attempt can loop twice, each loop with up to three calls to 
> usb_control_msg() and a device reset, with timeouts as long as 1 second.
> 
> In really bad cases this can tie things up for close to a minute.  We
> ought to be able to do better.  Some of the loops should be eliminated and
> some of the timeouts decreased.

Something like this?

	Regards
		Oliver

--- a/drivers/usb/core/hub.c	2007-03-01 11:17:53.000000000 +0100
+++ b/drivers/usb/core/hub.c	2007-03-01 12:13:08.000000000 +0100
@@ -70,6 +70,7 @@
 
 	unsigned		has_indicators:1;
 	u8			indicator[USB_MAXCHILDREN];
+	unsigned long		last_failed[USB_MAXCHILDREN];
 	struct delayed_work	leds;
 };
 
@@ -2419,7 +2420,7 @@
 	struct usb_device *hdev = hub->hdev;
 	struct device *hub_dev = hub->intfdev;
 	u16 wHubCharacteristics = le16_to_cpu(hub->descriptor->wHubCharacteristics);
-	int status, i;
+	int status, i, retries;
  
 	dev_dbg (hub_dev,
 		"port %d, status %04x, change %04x, %s\n",
@@ -2447,7 +2448,7 @@
 			dev_err (hub_dev,
 				"connect-debounce failed, port %d disabled\n",
 				port1);
-			goto done;
+			goto failed;
 		}
 		portstatus = status;
 	}
@@ -2461,7 +2462,7 @@
 			set_port_feature(hdev, port1, USB_PORT_FEAT_POWER);
  
 		if (portstatus & USB_PORT_STAT_ENABLE)
-  			goto done;
+  			goto failed;
 		return;
 	}
 
@@ -2478,7 +2479,11 @@
 	}
 #endif
 
-	for (i = 0; i < SET_CONFIG_TRIES; i++) {
+	/* we give short shrift if we had a failure within the last 2 hours */
+	retries = hub->last_failed[port1 - 1] &&
+		time_after(hub->last_failed[port1 - 1] + HZ * 60 * 60 * 2, jiffies) ?
+		1 : SET_CONFIG_TRIES;
+	for (i = 0; i < retries; i++) {
 		struct usb_device *udev;
 
 		/* reallocate for each attempt, since references
@@ -2580,6 +2585,7 @@
 		if (status)
 			dev_dbg(hub_dev, "%dmA power budget left\n", status);
 
+		hub->last_failed[port1 - 1] = 0; /*all former errors forgiven */
 		return;
 
 loop_disable:
@@ -2591,7 +2597,9 @@
 		if (status == -ENOTCONN)
 			break;
 	}
- 
+
+failed:
+	hub->last_failed[port1 - 1] = jiffies;
 done:
 	hub_port_disable(hub, port1, 1);
 }

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