Commit 93c8bf45 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
Browse files

USB core: don't match interface descriptors for vendor-specific devices 



This patch (as804) makes USB driver matching ignore the interface
class, subclass, and protocol if the device class is Vendor Specific.
Drivers can override this policy by specifying a Vendor ID as part
of the match; then vendor-specific matches are allowed.

Linus Walleij has reported a problem this patch fixes.  When a
particular mass-storage device is switched from mass-storage mode to
Media Transfer Protocol, the interface class remains set to mass-storage
and usb-storage binds to it erroneously, even though the device class
changes to Vendor-Specific.

This may cause a problem for some drivers until their match records can
be updated to include Vendor IDs.  But if it does, then those records
were broken to begin with.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 6d8fc4d2

drivers/usb/core/driver.c

+21 −1
Original line number Diff line number Diff line
@@ -408,6 +408,16 @@ static int usb_match_one_id(struct usb_interface *interface, 
	    (id->bDeviceProtocol != dev->descriptor.bDeviceProtocol))

		return 0;



	/* The interface class, subclass, and protocol should never be

	 * checked for a match if the device class is Vendor Specific,

	 * unless the match record specifies the Vendor ID. */

	if (dev->descriptor.bDeviceClass == USB_CLASS_VENDOR_SPEC &&

			!(id->match_flags & USB_DEVICE_ID_MATCH_VENDOR) &&

			(id->match_flags & (USB_DEVICE_ID_MATCH_INT_CLASS |

				USB_DEVICE_ID_MATCH_INT_SUBCLASS |

				USB_DEVICE_ID_MATCH_INT_PROTOCOL)))

		return 0;



	if ((id->match_flags & USB_DEVICE_ID_MATCH_INT_CLASS) &&

	    (id->bInterfaceClass != intf->desc.bInterfaceClass))

		return 0;
@@ -476,7 +486,17 @@ static int usb_match_one_id(struct usb_interface *interface, 
 * most general; they let drivers bind to any interface on a

 * multiple-function device.  Use the USB_INTERFACE_INFO

 * macro, or its siblings, to match class-per-interface style

 * devices (as recorded in bDeviceClass).

 * devices (as recorded in bInterfaceClass).

 *

 * Note that an entry created by USB_INTERFACE_INFO won't match

 * any interface if the device class is set to Vendor-Specific.

 * This is deliberate; according to the USB spec the meanings of

 * the interface class/subclass/protocol for these devices are also

 * vendor-specific, and hence matching against a standard product

 * class wouldn't work anyway.  If you really want to use an

 * interface-based match for such a device, create a match record

 * that also specifies the vendor ID.  (Unforunately there isn't a

 * standard macro for creating records like this.)

 *

 * Within those groups, remember that not all combinations are

 * meaningful.  For example, don't give a product version range

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