aes2550: Complete deactivation from dev_deactivate on broken loops

The driver relied on a running finger-detection or capture callback to
observe the deactivating flag and call complete_deactivation(). When the
async loop was broken by a session error from a terminal callback (such
as capture_sm_complete), no further iteration was left to notice the
flag, so the deactivation never completed.

Rather than scatter complete_deactivation() calls after every
fpi_image_device_session_error(), track whether an operation is actually
pending with an "active" flag and let dev_deactivate() complete the
request itself when nothing is in flight.

This keeps the deactivation lifecycle owned by dev_deactivate.

libfprint/drivers/aes2550.c

@@ -57,6 +57,7 @@ struct _FpiDeviceAes2550
 
   GSList       *strips;
   size_t        strips_len;
+  gboolean      active;
   gboolean      deactivating;
   int           heartbeat_cnt;
 };
@@ -91,14 +92,21 @@ finger_det_data_cb (FpiUsbTransfer *transfer, FpDevice *device,
                     gpointer user_data, GError *error)
 {
   FpImageDevice *dev = FP_IMAGE_DEVICE (device);
+  FpiDeviceAes2550 *self = FPI_DEVICE_AES2550 (device);
   unsigned char *data = transfer->buffer;
 
   if (error)
     {
-      /* Ensure deactivation completes even though the finger-detect
+      /* The finger-detect loop is broken; it no longer has a pending
-       * loop is broken by the session error. */
+       * operation. Clear the active flag so that the deactivation
-      fpi_image_device_session_error (dev, error);
+       * triggered by the session error (or an in-flight cancellation)
+       * can complete. */
+      self->active = FALSE;
+
+      if (self->deactivating)
         complete_deactivation (dev);
+      else
+        fpi_image_device_session_error (dev, error);
       return;
     }
 
@@ -125,13 +133,20 @@ finger_det_reqs_cb (FpiUsbTransfer *t, FpDevice *device,
 {
   FpiUsbTransfer *transfer;
   FpImageDevice *dev = FP_IMAGE_DEVICE (device);
+  FpiDeviceAes2550 *self = FPI_DEVICE_AES2550 (device);
 
   if (error)
     {
-      /* Ensure deactivation completes even though the finger-detect
+      /* The finger-detect loop is broken; it no longer has a pending
-       * loop is broken by the session error. */
+       * operation. Clear the active flag so that the deactivation
-      fpi_image_device_session_error (dev, error);
+       * triggered by the session error (or an in-flight cancellation)
+       * can complete. */
+      self->active = FALSE;
+
+      if (self->deactivating)
         complete_deactivation (dev);
+      else
+        fpi_image_device_session_error (dev, error);
       return;
     }
 
@@ -383,12 +398,12 @@ capture_sm_complete (FpiSsm *ssm, FpDevice *_dev, GError *error)
     }
   else if (error)
     {
-      /* fpi_image_device_session_error() will trigger dev_deactivate()
+      /* The capture SSM has terminated, so no completion handler is left
-       * which sets the deactivating flag. Since the SSM is terminating,
+       * to observe the deactivation that the session error triggers.
-       * complete_deactivation() must be called here to avoid a deadlock
+       * Clear the active flag so dev_deactivate() completes it directly.
-       * where nothing checks the deactivating flag. */
+       */
+      self->active = FALSE;
       fpi_image_device_session_error (dev, error);
-      complete_deactivation (dev);
     }
   else
     {
@@ -506,12 +521,16 @@ activate_run_state (FpiSsm *ssm, FpDevice *dev)
 static void
 activate_sm_complete (FpiSsm *ssm, FpDevice *_dev, GError *error)
 {
+  FpiDeviceAes2550 *self = FPI_DEVICE_AES2550 (_dev);
   FpImageDevice *dev = FP_IMAGE_DEVICE (_dev);
 
   fpi_image_device_activate_complete (dev, error);
 
   if (!error)
+    {
+      self->active = TRUE;
       start_finger_detection (dev);
+    }
 }
 
 static void
@@ -528,6 +547,13 @@ dev_deactivate (FpImageDevice *dev)
 {
   FpiDeviceAes2550 *self = FPI_DEVICE_AES2550 (dev);
 
+  if (!self->active)
+    {
+      /* No operation is pending, so complete it right away. */
+      complete_deactivation (dev);
+      return;
+    }
+
   self->deactivating = TRUE;
 }
 
@@ -539,6 +565,7 @@ complete_deactivation (FpImageDevice *dev)
   G_DEBUG_HERE ();
 
   self->deactivating = FALSE;
+  self->active = FALSE;
   g_slist_free (self->strips);
   self->strips = NULL;
   self->strips_len = 0;