diff --git a/tests/hwsim/tshark.py b/tests/hwsim/tshark.py
index 55e06175b..d5984ebfe 100644
--- a/tests/hwsim/tshark.py
+++ b/tests/hwsim/tshark.py
@@ -16,14 +16,15 @@ logger = logging.getLogger()
 _tshark_filter_arg = '-Y'
 
 def run_tshark(filename, filter, display=None):
+    global _tshark_filter_arg
+
     # wait a bit to make it more likely for wlantest sniffer to have captured
     # and written the results into a file that we can process here
     time.sleep(1)
 
     try:
         arg = [ "tshark", "-r", filename,
-                _tshark_filter_arg, "wlan.fc.type_subtype == 4",
-                "-Tfields", ]
+                _tshark_filter_arg, filter ]
         if display:
             arg.append('-Tfields')
             for d in display: