shelldriver: Silence kernel earlier

Moves up the call to silence the kernel to the console expect loop. This
ensures that the kernel has been silenced before the prompt is checked,
as dmesg output can interrupt it and cause failures.

Signed-off-by: Joshua Watt <[email protected]>

Author: JoshuaWatt

labgrid/driver/shelldriver.py

@@ -79,9 +79,6 @@ def on_activate(self):
 
             self._put_ssh_key(keyfile_path)
 
-        # Turn off Kernel Messages to the console
-        self._run("dmesg -n 1")
-
     def on_deactivate(self):
         self._status = 0
 
@@ -133,6 +130,7 @@ def _await_login(self):
         # occours, we can't lose any data this way.
         last_before = b''
         did_login = False
+        did_silence_kernel = False
 
         while True:
             index, before, _, _ = self.console.expect(
@@ -141,10 +139,15 @@ def _await_login(self):
             )
 
             if index == 0:
-                # we got a promt. no need for any further action to activate
-                # this driver.
-                self.status = 1
-                break
+                if did_login and not did_silence_kernel:
+                    # Silence the kernel and wait for another prompt
+                    self.console.sendline("dmesg -n 1")
+                    did_silence_kernel = True
+                else:
+                    # we got a prompt. no need for any further action to
+                    # activate this driver.
+                    self.status = 1
+                    break
 
             elif index == 1:
                 # we need to login