1 files changed, 41 insertions, 1 deletions

diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index 2d4fd530e5e4..dd3482328ad2 100644
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -1,4 +1,5 @@
 #include <linux/usb.h>
+#include <linux/usb/ch9.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/slab.h>
@@ -49,7 +50,7 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
         unsigned char *buffer0 = buffer;
         struct usb_endpoint_descriptor *d;
         struct usb_host_endpoint *endpoint;
-        int n, i;
+        int n, i, j;
 
         d = (struct usb_endpoint_descriptor *) buffer;
         buffer += d->bLength;
@@ -84,6 +85,45 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
         memcpy(&endpoint->desc, d, n);
         INIT_LIST_HEAD(&endpoint->urb_list);
 
+        /* If the bInterval value is outside the legal range,
+         * set it to a default value: 32 ms */
+        i = 0;          /* i = min, j = max, n = default */
+        j = 255;
+        if (usb_endpoint_xfer_int(d)) {
+                i = 1;
+                switch (to_usb_device(ddev)->speed) {
+                case USB_SPEED_HIGH:
+                        n = 9;          /* 32 ms = 2^(9-1) uframes */
+                        j = 16;
+                        break;
+                default:                /* USB_SPEED_FULL or _LOW */
+                        /* For low-speed, 10 ms is the official minimum.
+                         * But some "overclocked" devices might want faster
+                         * polling so we'll allow it. */
+                        n = 32;
+                        break;
+                }
+        } else if (usb_endpoint_xfer_isoc(d)) {
+                i = 1;
+                j = 16;
+                switch (to_usb_device(ddev)->speed) {
+                case USB_SPEED_HIGH:
+                        n = 9;          /* 32 ms = 2^(9-1) uframes */
+                        break;
+                default:                /* USB_SPEED_FULL */
+                        n = 6;          /* 32 ms = 2^(6-1) frames */
+                        break;
+                }
+        }
+        if (d->bInterval < i || d->bInterval > j) {
+                dev_warn(ddev, "config %d interface %d altsetting %d "
+                    "endpoint 0x%X has an invalid bInterval %d, "
+                    "changing to %d\n",
+                    cfgno, inum, asnum,
+                    d->bEndpointAddress, d->bInterval, n);
+                endpoint->desc.bInterval = n;
+        }
+
         /* Skip over any Class Specific or Vendor Specific descriptors;
          * find the next endpoint or interface descriptor */
         endpoint->extra = buffer;