From stern@rowland.harvard.edu Mon May 22 13:47:15 2006
Date: Mon, 22 May 2006 16:47:13 -0400 (EDT)
From: Alan Stern <stern@rowland.harvard.edu>
To: Greg KH <greg@kroah.com>, David Brownell <david-b@pacbell.net>
cc: USB development list <linux-usb-devel@lists.sourceforge.net>
Subject: usbtest: report errors in iso tests
Message-ID: <Pine.LNX.4.44L0.0605221643560.5848-100000@iolanthe.rowland.org>

This patch (as693b) makes the usbtest driver report errors in the
isochronous bulk transfer tests instead of always returning 0.  As an
arbitrary cutoff, an error is returned if more than 10% of the packet
transfers fail.  It also stops a test immediately upon receiving an URB
submission error.

For a test harness, it's especially important to report when errors occur!

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

---
 drivers/usb/misc/usbtest.c |   36 +++++++++++++++++++++++++++++-------
 1 file changed, 29 insertions(+), 7 deletions(-)

--- gregkh-2.6.orig/drivers/usb/misc/usbtest.c
+++ gregkh-2.6/drivers/usb/misc/usbtest.c
@@ -1337,7 +1337,9 @@ struct iso_context {
 	unsigned		pending;
 	spinlock_t		lock;
 	struct completion	done;
+	int			submit_error;
 	unsigned long		errors;
+	unsigned long		packet_count;
 	struct usbtest_dev	*dev;
 };
 
@@ -1348,10 +1350,14 @@ static void iso_callback (struct urb *ur
 	spin_lock(&ctx->lock);
 	ctx->count--;
 
+	ctx->packet_count += urb->number_of_packets;
 	if (urb->error_count > 0)
 		ctx->errors += urb->error_count;
+	else if (urb->status != 0)
+		ctx->errors += urb->number_of_packets;
 
-	if (urb->status == 0 && ctx->count > (ctx->pending - 1)) {
+	if (urb->status == 0 && ctx->count > (ctx->pending - 1)
+			&& !ctx->submit_error) {
 		int status = usb_submit_urb (urb, GFP_ATOMIC);
 		switch (status) {
 		case 0:
@@ -1362,6 +1368,8 @@ static void iso_callback (struct urb *ur
 					status);
 			/* FALLTHROUGH */
 		case -ENODEV:			/* disconnected */
+		case -ESHUTDOWN:		/* endpoint disabled */
+			ctx->submit_error = 1;
 			break;
 		}
 	}
@@ -1371,8 +1379,8 @@ static void iso_callback (struct urb *ur
 	if (ctx->pending == 0) {
 		if (ctx->errors)
 			dev_dbg (&ctx->dev->intf->dev,
-				"iso test, %lu errors\n",
-				ctx->errors);
+				"iso test, %lu errors out of %lu\n",
+				ctx->errors, ctx->packet_count);
 		complete (&ctx->done);
 	}
 done:
@@ -1433,15 +1441,14 @@ test_iso_queue (struct usbtest_dev *dev,
 	struct usb_device	*udev;
 	unsigned		i;
 	unsigned long		packets = 0;
-	int			status;
+	int			status = 0;
 	struct urb		*urbs[10];	/* FIXME no limit */
 
 	if (param->sglen > 10)
 		return -EDOM;
 
+	memset(&context, 0, sizeof context);
 	context.count = param->iterations * param->sglen;
-	context.pending = param->sglen;
-	context.errors = 0;
 	context.dev = dev;
 	init_completion (&context.done);
 	spin_lock_init (&context.lock);
@@ -1473,6 +1480,7 @@ test_iso_queue (struct usbtest_dev *dev,
 
 	spin_lock_irq (&context.lock);
 	for (i = 0; i < param->sglen; i++) {
+		++context.pending;
 		status = usb_submit_urb (urbs [i], SLAB_ATOMIC);
 		if (status < 0) {
 			ERROR (dev, "submit iso[%d], error %d\n", i, status);
@@ -1483,12 +1491,26 @@ test_iso_queue (struct usbtest_dev *dev,
 
 			simple_free_urb (urbs [i]);
 			context.pending--;
+			context.submit_error = 1;
+			break;
 		}
 	}
 	spin_unlock_irq (&context.lock);
 
 	wait_for_completion (&context.done);
-	return 0;
+
+	/*
+	 * Isochronous transfers are expected to fail sometimes.  As an
+	 * arbitrary limit, we will report an error if any submissions
+	 * fail or if the transfer failure rate is > 10%.
+	 */
+	if (status != 0)
+		;
+	else if (context.submit_error)
+		status = -EACCES;
+	else if (context.errors > context.packet_count / 10)
+		status = -EIO;
+	return status;
 
 fail:
 	for (i = 0; i < param->sglen; i++) {