[patch] increase usbdevfs max isoc buffer size

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The current limit only allows isochronous transfers up to 32kbyte/urb,
updating this to 192 kbyte/urb improves the reliability of the
transfer. USB 2.0 transfer is possible with 32kbyte but increases the
chance of corrupted/incomplete data when the system is performing some
other tasks in the background.

http://www.spinics.net/lists/linux-usb/msg19955.html

Signed-off-by: Markus Rechberger <mrechberger@xxxxxxxxx>
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 4247ecc..d653787 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1097,7 +1097,8 @@ static int proc_do_submiturb(struct dev_state *ps, struct usbdevfs_urb *uurb,
 			}
 			totlen += isopkt[u].length;
 		}
-		if (totlen > 32768) {
+		/* 3072 * 64 microframes */
+		if (totlen > 196608) {
 			kfree(isopkt);
 			return -EINVAL;
 		}

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