nvdemux: Do not stop the monitor and retry after reboots

Author: mangelajo

packages/jumpstarter-driver-pyserial/jumpstarter_driver_pyserial/nvdemux/driver.py

@@ -120,12 +120,16 @@ async def connect(self):
             # Use a short sleep to allow checking ready state
             await sleep(0.1)
 
-        # Get the current pts path from manager
+        # Get the current pts path from manager (retry until timeout)
         manager = DemuxerManager.get_instance()
+        pts_start = time.monotonic()
         pts_path = manager.get_pts_path(str(self.uuid))
-
-        if not pts_path:
-            raise RuntimeError("Demuxer ready but no pts path available")
+        while not pts_path:
+            elapsed = time.monotonic() - pts_start
+            if elapsed >= self.timeout:
+                raise TimeoutError("Demuxer ready but no pts path available after retrying")
+            await sleep(self.poll_interval)
+            pts_path = manager.get_pts_path(str(self.uuid))
 
         cps_info = f", cps: {self.cps}" if self.cps is not None else ""
         self.logger.info("Connecting to %s, baudrate: %d%s", pts_path, self.baudrate, cps_info)

packages/jumpstarter-driver-pyserial/jumpstarter_driver_pyserial/nvdemux/manager.py

@@ -163,8 +163,8 @@ def register_driver(
             # If target is already ready, notify immediately
             notify_args = self._get_ready_callback(target, callback)
 
-            # Start monitor thread if this is the first driver
-            if len(self._drivers) == 1:
+            # Start monitor thread only once
+            if not self._monitor_thread or not self._monitor_thread.is_alive():
                 self._start_monitor()
 
         if notify_args:
@@ -186,9 +186,7 @@ def unregister_driver(self, driver_id: str) -> None:
                 del self._drivers[driver_id]
                 logger.info("Unregistered driver %s (target: %s)", driver_id, target)
 
-                # Stop monitor thread if this was the last driver
-                if not self._drivers:
-                    self._stop_monitor()
+                # Keep monitor running even if no drivers remain
 
     def get_pts_path(self, driver_id: str) -> str | None:
         """Get the pts path for a registered driver.

packages/jumpstarter-driver-pyserial/jumpstarter_driver_pyserial/nvdemux/manager_test.py

@@ -426,10 +426,10 @@ def test_reference_counting():
             time.sleep(0.2)
             assert not mock_proc._terminated
 
-            # Unregister second driver - process should stop
+            # Unregister second driver - process should still continue (monitor stays running)
             manager.unregister_driver("driver2")
             time.sleep(0.2)
-            assert mock_proc._terminated
+            assert not mock_proc._terminated
 
             # Cleanup
             DemuxerManager.reset_instance()