Add ability to enable dev shm streaming on eiger

src/dodal/devices/detector/detector.py

@@ -43,6 +43,9 @@ class DetectorParams(BaseModel):
     detector_size_constants: DetectorSizeConstants = EIGER2_X_16M_SIZE
     beam_xy_converter: DetectorDistanceToBeamXYConverter
     run_number: int
+    enable_dev_shm: bool = (
+        False  # Remove in https://github.com/DiamondLightSource/hyperion/issues/1395
+    )
 
     class Config:
         arbitrary_types_allowed = True

src/dodal/devices/eiger.py

@@ -144,6 +144,9 @@ def stop(self, *args):
         self.disarm_detector()
         stop_status &= self.disable_roi_mode()
         stop_status.wait(self.GENERAL_STATUS_TIMEOUT)
+        # See https://github.com/DiamondLightSource/hyperion/issues/1395
+        LOGGER.info("Turning off Eiger dev/shm streaming")
+        self.odin.fan.dev_shm_enable.set(0).wait()
         LOGGER.info("Eiger has successfully been stopped")
 
     def disable_roi_mode(self):
@@ -320,6 +323,10 @@ def forward_bit_depth_to_filewriter(self):
             self.GENERAL_STATUS_TIMEOUT
         )
 
+    def change_dev_shm(self, enable_dev_shm: bool):
+        LOGGER.info(f"{'Enabling' if enable_dev_shm else 'Disabling'} dev shm")
+        return self.odin.fan.dev_shm_enable.set(1 if enable_dev_shm else 0)
+
     def disarm_detector(self):
         self.cam.acquire.set(0).wait(self.GENERAL_STATUS_TIMEOUT)
 
@@ -330,6 +337,7 @@ def do_arming_chain(self) -> Status:
             functions_to_do_arm.append(self.enable_roi_mode)
 
         arming_sequence_funcs = [
+            lambda: self.change_dev_shm(detector_params.enable_dev_shm),
             lambda: self.set_detector_threshold(detector_params.expected_energy_ev),
             self.set_cam_pvs,
             self.set_odin_number_of_frame_chunks,

src/dodal/devices/eiger_odin.py

@@ -19,6 +19,7 @@ class EigerFan(Device):
     series = Component(EpicsSignalRO, "CurrentSeries_RBV")
     offset = Component(EpicsSignalRO, "CurrentOffset_RBV")
     forward_stream = Component(EpicsSignalWithRBV, "ForwardStream")
+    dev_shm_enable = Component(EpicsSignalWithRBV, "DevShmCache")
 
 
 class OdinMetaListener(Device):

tests/devices/unit_tests/test_eiger.py

@@ -346,13 +346,16 @@ def test_given_failing_odin_when_stage_then_exception_raised(fake_eiger):
     assert error_contents in e.value.__str__()
 
 
+def set_up_eiger_to_stage_happily(fake_eiger: EigerDetector):
+    fake_eiger.odin.nodes.clear_odin_errors = MagicMock()
+    fake_eiger.odin.check_odin_initialised = MagicMock(return_value=(True, ""))
+    fake_eiger.odin.file_writer.file_path.put(True)
+
+
 @patch("dodal.devices.eiger.await_value")
 def test_stage_runs_successfully(mock_await, fake_eiger: EigerDetector):
     mock_await.return_value = finished_status()
-    fake_eiger.odin.nodes.clear_odin_errors = MagicMock()
-    fake_eiger.odin.check_odin_initialised = MagicMock()
-    fake_eiger.odin.check_odin_initialised.return_value = (True, "")
-    fake_eiger.odin.file_writer.file_path.put(True)
+    set_up_eiger_to_stage_happily(fake_eiger)
     fake_eiger.stage()
     fake_eiger.arming_status.wait(1)  # This should complete long before 1s
 
@@ -363,9 +366,7 @@ def test_given_stale_parameters_goes_high_before_callbacks_then_stale_parameters
     fake_eiger: EigerDetector,
 ):
     mock_await.return_value = Status(done=True)
-    fake_eiger.odin.nodes.clear_odin_errors = MagicMock()
-    fake_eiger.odin.check_odin_initialised = MagicMock(return_value=(True, ""))
-    fake_eiger.odin.file_writer.file_path.put(True)
+    set_up_eiger_to_stage_happily(fake_eiger)
 
     mock_eiger_odin_statuses(fake_eiger)
 
@@ -689,3 +690,35 @@ def test_stop_eiger_waits_for_status_functions_to_complete(
 ):
     fake_eiger.stop()
     mock_wait.assert_called()
+
+
+@pytest.mark.parametrize(
+    "enable_dev_shm, expected_set",
+    [
+        (True, 1),
+        (False, 0),
+    ],
+)
+@patch("dodal.devices.eiger.await_value")
+def test_given_dev_shm_when_stage_then_correctly_enable_disable_dev_shm(
+    mock_await,
+    enable_dev_shm: bool,
+    expected_set: int,
+    fake_eiger: EigerDetector,
+):
+    mock_await.return_value = finished_status()
+    set_up_eiger_to_stage_happily(fake_eiger)
+
+    fake_eiger.detector_params.enable_dev_shm = enable_dev_shm  # type:ignore
+
+    fake_eiger.stage()
+
+    assert fake_eiger.odin.fan.dev_shm_enable.get() == expected_set
+
+
+def test_when_eiger_is_stopped_then_dev_shm_disabled(fake_eiger: EigerDetector):
+    fake_eiger.odin.fan.dev_shm_enable.sim_put(1)  # type:ignore
+
+    fake_eiger.stop()
+
+    assert fake_eiger.odin.fan.dev_shm_enable.get() == 0