Check for the right interface with the two endpoints and
enable the altmode 1 to tell the gadget it can mount now.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
---
 tools/usb/p9_fwd.py | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/tools/usb/p9_fwd.py b/tools/usb/p9_fwd.py
index 1b479c931df9bfb0f7e7f2cf5a612764408f0828..32b138976e0da0f395d25036fce8fd7faffdadad 100755
--- a/tools/usb/p9_fwd.py
+++ b/tools/usb/p9_fwd.py
@@ -74,7 +74,7 @@ class Forwarder:
                 if dev.is_kernel_driver_active(intf.bInterfaceNumber):
                     dev.detach_kernel_driver(intf.bInterfaceNumber)
 
-            if intf.bInterfaceClass == 0xFF and intf.bInterfaceSubClass == 0xFF and intf.bInterfaceProtocol == 0x09:
+            if intf.bInterfaceClass == 0xFF and intf.bInterfaceSubClass == 0xFF and intf.bInterfaceProtocol == 0x09 and intf.bNumEndpoints == 2:
                 usb9pfs = intf
         if usb9pfs is None:
             raise ValueError("Interface not found")
@@ -103,6 +103,14 @@ class Forwarder:
         self.ep_in = ep_in
         self.dev = dev
 
+        logging.info(f"setting alt mode 1 interface:\n{usb9pfs}")
+        try:
+            self.dev.set_interface_altsetting(usb9pfs.bInterfaceNumber, 1)
+        except usb.core.USBError as e:
+            if e.errno == None:
+                logging.debug("could not switch to alt 1 retry", repr(e))
+                raise ValueError("mount is not ready yet")
+
         # create and connect socket
         self.s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         self.s.connect(server)

-- 
2.47.3