From: Alan Stern <[EMAIL PROTECTED]>
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 <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
---
drivers/usb/core/config.c | 15 +++++++++++++++
1 files changed, 15 insertions(+), 0 deletions(-)
diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index dd34823..9152e12 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;
--
1.5.2.2
-------------------------------------------------------------------------
This SF.net email is sponsored by DB2 Express
Download DB2 Express C - the FREE version of DB2 express and take
control of your XML. No limits. Just data. Click to get it now.
http://sourceforge.net/powerbar/db2/
_______________________________________________
linux-usb-devel@lists.sourceforge.net
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
