support drivers that can't use reset directly.

bumble/drivers/__init__.py

@@ -60,12 +60,23 @@ class Driver(abc.ABC):
 # Functions
 # -----------------------------------------------------------------------------
 async def get_driver_for_host(host):
-    """Probe all known diver classes until one returns a valid instance for a host,
-    or none is found.
+    """Probe diver classes until one returns a valid instance for a host, or none is
+    found.
+    If a "driver" HCI metadata entry is present, only that driver class will be probed.
     """
-    if driver := await rtk.Driver.for_host(host):
-        logger.debug("Instantiated RTK driver")
-        return driver
+    driver_classes = {"rtk": rtk.Driver}
+    if driver_name := host.hci_metadata.get("driver"):
+        # Only probe a single driver
+        probe_list = [driver_name]
+    else:
+        # Probe all drivers
+        probe_list = driver_classes.keys()
+
+    for driver_name in probe_list:
+        logger.debug(f"Probing {driver_name} driver class")
+        if driver := await rtk.Driver.for_host(host):
+            logger.debug(f"Instantiated {driver_name} driver")
+            return driver
 
     return None
 

bumble/drivers/rtk.py

@@ -470,8 +470,12 @@ class Driver:
             logger.debug("USB metadata not found")
             return False
 
-        vendor_id = host.hci_metadata.get("vendor_id", None)
-        product_id = host.hci_metadata.get("product_id", None)
+        if host.hci_metadata.get('driver') == 'rtk':
+            # Forced driver
+            return True
+
+        vendor_id = host.hci_metadata.get("vendor_id")
+        product_id = host.hci_metadata.get("product_id")
         if vendor_id is None or product_id is None:
             logger.debug("USB metadata not sufficient")
             return False
@@ -486,6 +490,9 @@ class Driver:
 
     @classmethod
     async def driver_info_for_host(cls, host):
+        await host.send_command(HCI_Reset_Command(), check_result=True)
+        host.ready = True  # Needed to let the host know the controller is ready.
+
         response = await host.send_command(
             HCI_Read_Local_Version_Information_Command(), check_result=True
         )