From 60aac1ec26b960fe77bf600457bc6c06f8aa7db4 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Fri, 8 Jun 2007 15:25:02 -0400 Subject: [PATCH] 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 Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/config.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c index dd3482328a..9152e12dcf 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; -- 2.39.5