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

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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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Stern 2006-10-18 16:41:51 -04:00 committed by Greg Kroah-Hartman
parent 6d8fc4d28d
commit 93c8bf45e0
1 changed files with 21 additions and 1 deletions
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22
drivers/usb/core/driver.c
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@ -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