[PATCH] USB: fix usbfs iso interval problem

In 2.6, ISO transfers on USB require a value for urb->interval ... which
usbfs didn't provide (until this patch), or let user mode drivers specify.

This patch initializes the urb->interval from the endpoint's descriptor,
so ISO transfers should now work from userspace.  It also fixes a related
problem for interrupt transfers.

drivers/usb/core/devio.c

@@ -873,6 +873,9 @@ static int proc_submiturb(struct dev_state *ps, void __user *arg)
 		/* arbitrary limit */
 		if (uurb.number_of_packets < 1 || uurb.number_of_packets > 128)
 			return -EINVAL;
+		if (!(ep_desc = usb_epnum_to_ep_desc(ps->dev, uurb.endpoint)))
+			return -ENOENT;
+		interval = 1 << min ((u8)15, ep_desc->bInterval - 1);
 		isofrmlen = sizeof(struct usbdevfs_iso_packet_desc) * uurb.number_of_packets;
 		if (!(isopkt = kmalloc(isofrmlen, GFP_KERNEL)))
 			return -ENOMEM;
@@ -898,6 +901,9 @@ static int proc_submiturb(struct dev_state *ps, void __user *arg)
 		uurb.number_of_packets = 0;
 		if (!(ep_desc = usb_epnum_to_ep_desc(ps->dev, uurb.endpoint)))
 			return -ENOENT;
+		if (ps->dev->speed == USB_SPEED_HIGH)
+			interval = 1 << min ((u8)15, ep_desc->bInterval - 1);
+		else
 			interval = ep_desc->bInterval;
 		if (uurb.buffer_length > 16384)
 			return -EINVAL;