CRAS: iodev_list - Check if pinned device is open already

cras_iodev can be opened and accessed by audio_thread
in two ways:
(1) UI enables an input/output audio node.
(2) An application creates a stream that pins to specific audio node.

This change adds a function to ask if the given device is already
in use by the audio_thread. It can be used to avoid unecessary
calls and possible multi thread access to iodev.

BUG=chromium:890242, chromium:863823
TEST=unittest

Change-Id: I24713e15f1039599abd3387fbc1bbe2c490efff1
Reviewed-on: https://chromium-review.googlesource.com/1257487
Commit-Ready: Hsinyu Chao <hychao@chromium.org>
Tested-by: Hsinyu Chao <hychao@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>

4 files changed, 59 insertions, 0 deletions

diff --git a/cras/src/server/audio_thread.c b/cras/src/server/audio_thread.c
index 8d53f1e3..7d208d88 100644
--- a/cras/src/server/audio_thread.c
+++ b/cras/src/server/audio_thread.c
@@ -38,6 +38,7 @@
 enum AUDIO_THREAD_COMMAND {
 	AUDIO_THREAD_ADD_OPEN_DEV,
 	AUDIO_THREAD_RM_OPEN_DEV,
+	AUDIO_THREAD_IS_DEV_OPEN,
 	AUDIO_THREAD_ADD_STREAM,
 	AUDIO_THREAD_DISCONNECT_STREAM,
 	AUDIO_THREAD_STOP,
@@ -398,6 +399,18 @@ static int thread_rm_open_dev(struct audio_thread *thread,
 	return 0;
 }
 
+/*
+ * Handles message from the main thread to check if an iodev is in the
+ * open dev list.
+ */
+static int thread_is_dev_open(struct audio_thread *thread,
+			      struct cras_iodev *iodev)
+{
+	struct open_dev *adev = dev_io_find_open_dev(
+			thread->open_devs[iodev->direction], iodev);
+	return !!adev;
+}
+
 /* Handles messages from the main thread to start ramping on a device. */
 static int thread_dev_start_ramp(struct audio_thread *thread,
 				 struct cras_iodev *iodev,
@@ -638,6 +651,13 @@ static int handle_playback_thread_message(struct audio_thread *thread)
 		ret = thread_rm_open_dev(thread, rmsg->dev);
 		break;
 	}
+	case AUDIO_THREAD_IS_DEV_OPEN: {
+		struct audio_thread_open_device_msg *rmsg;
+
+		rmsg = (struct audio_thread_open_device_msg *)msg;
+		ret = thread_is_dev_open(thread, rmsg->dev);
+		break;
+	}
 	case AUDIO_THREAD_STOP:
 		ret = 0;
 		err = audio_thread_send_response(thread, ret);
@@ -1256,6 +1276,18 @@ int audio_thread_rm_open_dev(struct audio_thread *thread,
 	return audio_thread_post_message(thread, &msg.header);
 }
 
+int audio_thread_is_dev_open(struct audio_thread *thread,
+			     struct cras_iodev *dev)
+{
+	struct audio_thread_open_device_msg msg;
+
+	if (!dev)
+		return 0;
+
+	init_open_device_msg(&msg, AUDIO_THREAD_IS_DEV_OPEN, dev);
+	return audio_thread_post_message(thread, &msg.header);
+}
+
 int audio_thread_dev_start_ramp(struct audio_thread *thread,
 				struct cras_iodev *dev,
 				enum CRAS_IODEV_RAMP_REQUEST request)
diff --git a/cras/src/server/audio_thread.h b/cras/src/server/audio_thread.h
index adeadd6c..e2c0d725 100644
--- a/cras/src/server/audio_thread.h
+++ b/cras/src/server/audio_thread.h
@@ -74,6 +74,14 @@ int audio_thread_add_open_dev(struct audio_thread *thread,
 int audio_thread_rm_open_dev(struct audio_thread *thread,
 			     struct cras_iodev *dev);
 
+/* Checks if dev is open and used by audio thread.
+ * Args:
+ *    thread - The thread accessing open devs.
+ *    dev - The device to check if it has already been open.
+ */
+int audio_thread_is_dev_open(struct audio_thread *thread,
+			     struct cras_iodev *dev);
+
 /* Adds an thread_callback to audio thread.
  * Args:
  *    fd - The file descriptor to be polled for the callback.
diff --git a/cras/src/server/cras_iodev_list.c b/cras/src/server/cras_iodev_list.c
index 02d58e07..2d5d5a50 100644
--- a/cras/src/server/cras_iodev_list.c
+++ b/cras/src/server/cras_iodev_list.c
@@ -683,6 +683,9 @@ static int init_pinned_device(struct cras_iodev *dev,
 {
 	int rc;
 
+	if (audio_thread_is_dev_open(audio_thread, dev))
+		return 0;
+
 	/* Make sure the active node is configured properly, it could be
 	 * disabled when last normal stream removed. */
 	dev->update_active_node(dev, dev->active_node->idx, 1);
diff --git a/cras/src/tests/iodev_list_unittest.cc b/cras/src/tests/iodev_list_unittest.cc
index f1e14649..5fb32aa3 100644
--- a/cras/src/tests/iodev_list_unittest.cc
+++ b/cras/src/tests/iodev_list_unittest.cc
@@ -36,6 +36,7 @@ static int audio_thread_set_active_dev_called;
 static cras_iodev *audio_thread_add_open_dev_dev;
 static int audio_thread_add_open_dev_called;
 static int audio_thread_rm_open_dev_called;
+static int audio_thread_is_dev_open_ret;
 static struct audio_thread thread;
 static struct cras_iodev loopback_input;
 static int cras_iodev_close_called;
@@ -114,6 +115,7 @@ class IoDevTestSuite : public testing::Test {
 
       audio_thread_disconnect_stream_called = 0;
       audio_thread_disconnect_stream_stream = NULL;
+      audio_thread_is_dev_open_ret = 0;
       cras_iodev_has_pinned_stream_ret.clear();
 
       sample_rates_[0] = 44100;
@@ -1374,6 +1376,14 @@ TEST_F(IoDevTestSuite, AddRemovePinnedStream) {
   EXPECT_EQ(5, update_active_node_called);
   // close pinned device
   EXPECT_EQ(&d1_, update_active_node_iodev_val[4]);
+
+  // Assume dev is already opened, add pin stream should not trigger another
+  // update_active_node call, but will trigger audio_thread_add_stream.
+  audio_thread_is_dev_open_ret = 1;
+  EXPECT_EQ(0, stream_add_cb(&rstream));
+  EXPECT_EQ(5, update_active_node_called);
+  EXPECT_EQ(2, audio_thread_add_stream_called);
+
   cras_iodev_list_deinit();
 }
 
@@ -1574,6 +1584,12 @@ int audio_thread_rm_open_dev(struct audio_thread *thread,
   return 0;
 }
 
+int audio_thread_is_dev_open(struct audio_thread *thread,
+			     struct cras_iodev *dev)
+{
+  return audio_thread_is_dev_open_ret;
+}
+
 int audio_thread_add_stream(struct audio_thread *thread,
                             struct cras_rstream *stream,
                             struct cras_iodev **devs,