aes3k: Re-send some commands for each capture

The driver seems to have relied on the device to be fully
deactivated and activated again for each capture. This is not the case
during enroll, and as such in can cause issues.

Try fixing this by splitting out the last few commands send to the
device and assuming that this starts the capture.

Fixes: #306

libfprint/drivers/aes3500.c

@@ -106,7 +106,9 @@ static struct aes_regwrite init_reqs[] = {
   { 0x9e, 0x53 },       /* clear challenge word bits */
   { 0x9f, 0x6b },       /* set some challenge word bits */
   { 0, 0 },
+};
 
+static struct aes_regwrite capture_reqs[] = {
   { 0x80, 0x00 },
   { 0x81, 0x00 },
   { 0, 0 },
@@ -155,4 +157,6 @@ fpi_device_aes3500_class_init (FpiDeviceAes3500Class *klass)
   aes_class->enlarge_factor = ENLARGE_FACTOR;
   aes_class->init_reqs = init_reqs;
   aes_class->init_reqs_len = G_N_ELEMENTS (init_reqs);
+  aes_class->capture_reqs = capture_reqs;
+  aes_class->capture_reqs_len = G_N_ELEMENTS (capture_reqs);
 }

libfprint/drivers/aes3k.c

@@ -42,7 +42,10 @@
 
 typedef struct
 {
-  GCancellable *img_trf_cancel;
+  /* This is used both as a flag that we are in a capture operation
+   * and for cancellation.
+   */
+  GCancellable *img_capture_cancel;
 } FpiDeviceAes3kPrivate;
 
 #define CTRL_TIMEOUT 1000
@@ -83,6 +86,9 @@ img_cb (FpiUsbTransfer *transfer, FpDevice *device,
   FpImage *img;
   int i;
 
+  /* Image capture operation is finished (error/completed) */
+  g_clear_object (&priv->img_capture_cancel);
+
   if (error)
     {
       if (g_error_matches (error,
@@ -91,13 +97,11 @@ img_cb (FpiUsbTransfer *transfer, FpDevice *device,
         {
           /* Cancellation implies we are deactivating. */
           g_error_free (error);
-          g_clear_object (&priv->img_trf_cancel);
           fpi_image_device_deactivate_complete (dev, NULL);
           return;
         }
 
       fpi_image_device_session_error (dev, error);
-      g_clear_object (&priv->img_trf_cancel);
       return;
     }
 
@@ -122,11 +126,10 @@ img_cb (FpiUsbTransfer *transfer, FpDevice *device,
   fpi_image_device_image_captured (dev, img);
 
   /* FIXME: rather than assuming finger has gone, we should poll regs until
-   * it really has, then restart the capture */
+   * it really has. */
   fpi_image_device_report_finger_status (dev, FALSE);
 
-  /* Note: We always restart the transfer, it may already be cancelled though. */
-  do_capture (dev);
+  /* Note: The transfer is re-started when we switch to the AWAIT_FINGER_ON state. */
 }
 
 static void
@@ -141,31 +144,51 @@ do_capture (FpImageDevice *dev)
   fpi_usb_transfer_fill_bulk (img_trf, EP_IN, cls->data_buflen);
   img_trf->short_is_error = TRUE;
   fpi_usb_transfer_submit (g_steal_pointer (&img_trf), 0,
-                           priv->img_trf_cancel,
+                           priv->img_capture_cancel,
                            img_cb, NULL);
 }
 
+static void
+capture_reqs_cb (FpImageDevice *dev, GError *result, void *user_data)
+{
+  FpiDeviceAes3k *self = FPI_DEVICE_AES3K (dev);
+  FpiDeviceAes3kPrivate *priv = fpi_device_aes3k_get_instance_private (self);
+
+  if (result)
+    {
+      g_clear_object (&priv->img_capture_cancel);
+      fpi_image_device_session_error (dev, result);
+      return;
+    }
+
+  /* FIXME: we never cancel a pending capture. So we are likely leaving the
+   * hardware in a bad state should we abort the capture operation and the
+   * user does not touch the device.
+   * But, we don't know how we might cancel, so just leave it as is. */
+  do_capture (dev);
+}
+
+static void
+do_capture_start (FpImageDevice *dev)
+{
+  FpiDeviceAes3k *self = FPI_DEVICE_AES3K (dev);
+  FpiDeviceAes3kClass *cls = FPI_DEVICE_AES3K_GET_CLASS (self);
+
+  aes_write_regv (dev, cls->capture_reqs, cls->capture_reqs_len, capture_reqs_cb, NULL);
+}
+
 static void
 init_reqs_cb (FpImageDevice *dev, GError *result, void *user_data)
 {
-  FpiDeviceAes3kPrivate *priv = fpi_device_aes3k_get_instance_private (FPI_DEVICE_AES3K (dev));
-
   fpi_image_device_activate_complete (dev, result);
-  if (!result)
-    {
-      priv->img_trf_cancel = g_cancellable_new ();
-      do_capture (dev);
-    }
 }
 
 static void
 aes3k_dev_activate (FpImageDevice *dev)
 {
   FpiDeviceAes3k *self = FPI_DEVICE_AES3K (dev);
-  FpiDeviceAes3kPrivate *priv = fpi_device_aes3k_get_instance_private (self);
   FpiDeviceAes3kClass *cls = FPI_DEVICE_AES3K_GET_CLASS (self);
 
-  g_assert (!priv->img_trf_cancel);
   aes_write_regv (dev, cls->init_reqs, cls->init_reqs_len, init_reqs_cb, NULL);
 }
 
@@ -175,13 +198,28 @@ aes3k_dev_deactivate (FpImageDevice *dev)
   FpiDeviceAes3k *self = FPI_DEVICE_AES3K (dev);
   FpiDeviceAes3kPrivate *priv = fpi_device_aes3k_get_instance_private (self);
 
-  /* Deactivation finishes from the cancellation handler */
-  if (priv->img_trf_cancel)
-    g_cancellable_cancel (priv->img_trf_cancel);
+  /* If a capture is running, then deactivation finishes from the cancellation handler */
+  if (priv->img_capture_cancel)
+    g_cancellable_cancel (priv->img_capture_cancel);
   else
     fpi_image_device_deactivate_complete (dev, NULL);
 }
 
+static void
+aes3k_dev_change_state (FpImageDevice *dev, FpiImageDeviceState state)
+{
+  FpiDeviceAes3k *self = FPI_DEVICE_AES3K (dev);
+  FpiDeviceAes3kPrivate *priv = fpi_device_aes3k_get_instance_private (self);
+
+  if (state == FPI_IMAGE_DEVICE_STATE_AWAIT_FINGER_ON)
+    {
+      g_assert (!priv->img_capture_cancel);
+      priv->img_capture_cancel = g_cancellable_new ();
+
+      do_capture_start (dev);
+    }
+}
+
 static void
 fpi_device_aes3k_init (FpiDeviceAes3k *self)
 {
@@ -224,6 +262,7 @@ fpi_device_aes3k_class_init (FpiDeviceAes3kClass *klass)
   img_class->img_open = aes3k_dev_init;
   img_class->img_close = aes3k_dev_deinit;
   img_class->activate = aes3k_dev_activate;
+  img_class->change_state = aes3k_dev_change_state;
   img_class->deactivate = aes3k_dev_deactivate;
 
   /* Extremely low due to low image quality. */

libfprint/drivers/aes3k.h

@@ -57,4 +57,6 @@ struct _FpiDeviceAes3kClass
   gsize                data_buflen;    /* buffer length of usb bulk transfer */
   struct aes_regwrite *init_reqs;       /* initial values sent to device */
   gsize                init_reqs_len;
+  struct aes_regwrite *capture_reqs;       /* capture values sent to device */
+  gsize                capture_reqs_len;
 };

libfprint/drivers/aes4000.c

@@ -103,7 +103,9 @@ static struct aes_regwrite init_reqs[] = {
   { 0x9e, 0x53 },       /* clear challenge word bits */
   { 0x9f, 0x6b },       /* set some challenge word bits */
   { 0, 0 },
+};
 
+static struct aes_regwrite capture_reqs[] = {
   { 0x80, 0x00 },
   { 0x81, 0x00 },
   { 0, 0 },
@@ -152,4 +154,6 @@ fpi_device_aes4000_class_init (FpiDeviceAes4000Class *klass)
   aes_class->enlarge_factor = ENLARGE_FACTOR;
   aes_class->init_reqs = init_reqs;
   aes_class->init_reqs_len = G_N_ELEMENTS (init_reqs);
+  aes_class->capture_reqs = capture_reqs;
+  aes_class->capture_reqs_len = G_N_ELEMENTS (capture_reqs);
 }