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authorAlan Stern <stern@rowland.harvard.edu>2006-10-18 16:41:51 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2006-12-01 14:23:27 -0800
commit93c8bf45e083b89dffe3a708363c15c1b220c723 (patch)
treefa9b05fdfdc9ba2d75a2fee9729b8a553b23c678 /drivers/usb
parent6d8fc4d28deaf828606c19fb743fbe94aeab4caf (diff)
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 <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb')
-rw-r--r--drivers/usb/core/driver.c22
1 files changed, 21 insertions, 1 deletions
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 113e484c763..401d76f1341 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