This patch adds code to check for endpoint descriptor bInterval values
outside the legal limits. Illegal values are fixed or set to 32 ms, which
seems like a reasonable default.
This fixes Bugzilla #8432.
Signed-off-by: Laurent Pinchart <[EMAIL PROTECTED]>
diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index bfb3731..ecf5838 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 +85,51 @@ static int usb_parse_endpoint(struct device *ddev, int
cfgno, int inum,
memcpy(&endpoint->desc, d, n);
INIT_LIST_HEAD(&endpoint->urb_list);
+ /* Fix up bInterval values outside the legal range. Use 32 ms if no
+ * proper value can be guessed. */
+ 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:
+ /* Many device manufacturers are using full-speed
+ * bInterval values in high-speed interrupt endpoint
+ * descriptors. Try to fix those and fall back to a
+ * 32 ms default value otherwise. */
+ n = fls(d->bInterval*8);
+ if (n == 0)
+ 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;
--
1.5.1.6
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