dect
/
linux-2.6
Archived
13
0
Fork 0
Code Releases Activity

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>
This commit is contained in:
Alan Stern 2007-06-08 15:25:02 -04:00 committed by Greg Kroah-Hartman
parent 52f6b5e1f1
commit 60aac1ec26
1 changed files with 15 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/usb/core/config.c
View File

@ -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;