USB: allow interrupt transfers to WUSB devices

Check urb->interval on interrupt transfers and allow those with valid
values (6 <= interval <= 16).

Signed-off-by: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 18 insertions, 4 deletions

diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c
index 0885d4abdc62..e7cae1334693 100644
--- a/drivers/usb/core/urb.c
+++ b/drivers/usb/core/urb.c
@@ -429,8 +429,16 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
         case USB_ENDPOINT_XFER_ISOC:
         case USB_ENDPOINT_XFER_INT:
                 /* too small? */
-                if (urb->interval <= 0)
-                        return -EINVAL;
+                switch (dev->speed) {
+                case USB_SPEED_VARIABLE:
+                        if (urb->interval < 6)
+                                return -EINVAL;
+                        break;
+                default:
+                        if (urb->interval <= 0)
+                                return -EINVAL;
+                        break;
+                }
                 /* too big? */
                 switch (dev->speed) {
                 case USB_SPEED_SUPER:   /* units are 125us */
@@ -438,6 +446,10 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
                         if (urb->interval > (1 << 15))
                                 return -EINVAL;
                         max = 1 << 15;
+                case USB_SPEED_VARIABLE:
+                        if (urb->interval > 16)
+                                return -EINVAL;
+                        break;
                 case USB_SPEED_HIGH:    /* units are microframes */
                         /* NOTE usb handles 2^15 */
                         if (urb->interval > (1024 * 8))
@@ -461,8 +473,10 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
                 default:
                         return -EINVAL;
                 }
-                /* Round down to a power of 2, no more than max */
-                urb->interval = min(max, 1 << ilog2(urb->interval));
+                if (dev->speed != USB_SPEED_VARIABLE) {
+                        /* Round down to a power of 2, no more than max */
+                        urb->interval = min(max, 1 << ilog2(urb->interval));
+                }
         }
 
         return usb_hcd_submit_urb(urb, mem_flags);