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authorAlan Stern <stern@rowland.harvard.edu>2007-06-08 15:25:02 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2007-07-12 16:34:31 -0700
commit60aac1ec26b960fe77bf600457bc6c06f8aa7db4 (patch)
tree04f9c9efa42391e85c9590f9859dedc9650ef3c7
parent52f6b5e1f15fa8c06efa69a4b5faa69c04707c92 (diff)
USB: Handle bogus low-speed Bulk endpoints
A noticeable number of low-speed devices mistakenly include descriptors for Bulk endpoints, which is forbidden by the USB spec. In an attempt to make such devices more usable, this patch (as924) converts the descriptors to Interrupt with an interval of 1 ms. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/usb/core/config.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index dd3482328ad..9152e12dcf7 100644
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -124,6 +124,21 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum,
endpoint->desc.bInterval = n;
}
+ /* Some buggy low-speed devices have Bulk endpoints, which is
+ * explicitly forbidden by the USB spec. In an attempt to make
+ * them usable, we will try treating them as Interrupt endpoints.
+ */
+ if (to_usb_device(ddev)->speed == USB_SPEED_LOW &&
+ usb_endpoint_xfer_bulk(d)) {
+ dev_warn(ddev, "config %d interface %d altsetting %d "
+ "endpoint 0x%X is Bulk; changing to Interrupt\n",
+ cfgno, inum, asnum, d->bEndpointAddress);
+ endpoint->desc.bmAttributes = USB_ENDPOINT_XFER_INT;
+ endpoint->desc.bInterval = 1;
+ if (le16_to_cpu(endpoint->desc.wMaxPacketSize) > 8)
+ endpoint->desc.wMaxPacketSize = cpu_to_le16(8);
+ }
+
/* Skip over any Class Specific or Vendor Specific descriptors;
* find the next endpoint or interface descriptor */
endpoint->extra = buffer;