From 93c8bf45e083b89dffe3a708363c15c1b220c723 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 18 Oct 2006 16:41:51 -0400 Subject: [PATCH] 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: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/driver.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c index 113e484c763e..401d76f13419 100644 --- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -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 -- 2.20.1