The USB_DEVICE_INTERFACE_NUMBER matching macro assumes that
the { vendorid, productid, interfacenumber } set uniquely
identifies one specific function. This has proven to fail
for some configurable devices. One example is the Quectel
EM06/EP06 where the same interface number can be either
QMI or MBIM, without the device ID changing either.
Fix by requiring the vendor-specific class for interface number
based matching. Functions of other classes can and should use
class based matching instead.
Fixes: 03304bcb5ec4 ("net: qmi_wwan: use fixed interface number matching")
Signed-off-by: Bjørn Mork <bj...@mork.no>
---
It's quite possible that the fix should be integrated in the
USB_DEVICE_INTERFACE_NUMBER macro instead. But that has grown a few
other users since it was added, so changing it now seems risky.
Another option is of course adding a new match macro with the
USB_CLASS_VENDOR_SPEC match integrated. Maybe best?
But I'm proposing this as-is for now, since this quickfix seems most
suitable for stable backporting.
drivers/net/usb/qmi_wwan.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c
index 51c68fc416fa..42565dd33aa6 100644
--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -1344,6 +1344,18 @@ static int qmi_wwan_probe(struct usb_interface *intf,
id->driver_info = (unsigned long)&qmi_wwan_info;
}
+ /* There are devices where the same interface number can be
+ * configured as different functions. We should only bind to
+ * vendor specific functions when matching on interface number
+ */
+ if (id->match_flags & USB_DEVICE_ID_MATCH_INT_NUMBER &&
+ desc->bInterfaceClass != USB_CLASS_VENDOR_SPEC) {
+ dev_dbg(&intf->dev,
+ "Rejecting interface number match for class %02x\n",
+ desc->bInterfaceClass);
+ return -ENODEV;
+ }
+
/* Quectel EC20 quirk where we've QMI on interface 4 instead of 0 */
if (quectel_ec20_detected(intf) && desc->bInterfaceNumber == 0) {
dev_dbg(&intf->dev, "Quectel EC20 quirk, skipping interface
0\n");
--
2.11.0
