refactor(core): drain the BLE event queue whenever layout is running

[no changelog]

core/src/trezor/ui/__init__.py

@@ -381,6 +381,9 @@ class Layout(Generic[T]):
             yield self._handle_input_iface(io.BUTTON, self.layout.button_event)
         if utils.USE_TOUCH:
             yield self._handle_input_iface(io.TOUCH, self.layout.touch_event)
+        if utils.USE_BLE:
+            # most layouts don't care but we don't want to keep stale events in the queue
+            yield self._handle_ble_events()
 
     def _handle_input_iface(
         self, iface: int, event_call: Callable[..., LayoutState | None]
@@ -430,6 +433,18 @@ class Layout(Generic[T]):
             except Exception:
                 raise
 
+    if utils.USE_BLE:
+
+        async def _handle_ble_events(self) -> None:
+            blecheck = loop.wait(io.BLE_EVENT)
+            try:
+                while True:
+                    event = await blecheck
+                    log.debug(__name__, "BLE event: %s", event)
+                    self._event(self.layout.ble_event, *event)
+            except Shutdown:
+                return
+
     def _task_finalizer(self, task: loop.Task, value: Any) -> None:
         if value is None:
             # all is good

core/src/trezor/ui/layouts/homescreen.py

@@ -3,7 +3,7 @@ from typing import TYPE_CHECKING
 import storage.cache as storage_cache
 import trezorui_api
 from storage.cache_common import APP_COMMON_BUSY_DEADLINE_MS
-from trezor import TR, ui, utils
+from trezor import TR, ui
 
 if TYPE_CHECKING:
     from typing import Any, Callable, Iterator, ParamSpec, TypeVar
@@ -101,21 +101,9 @@ class Homescreen(HomescreenBase):
             event = await usbcheck
             self._event(self.layout.usb_event, event)
 
-    if utils.USE_BLE:
-
-        async def ble_checker_task(self) -> None:
-            from trezor import io, loop
-
-            blecheck = loop.wait(io.BLE_EVENT)
-            while True:
-                event = await blecheck
-                self._event(self.layout.ble_event, *event)
-
     def create_tasks(self) -> Iterator[loop.Task]:
         yield from super().create_tasks()
         yield self.usb_checker_task()
-        if utils.USE_BLE:
-            yield self.ble_checker_task()
 
 
 class Lockscreen(HomescreenBase):