From b406d3ac1676184453a6e1fcb669b2c352ce06f9 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Tue, 12 Nov 2013 10:21:16 -0600
Subject: apps/examples/i2schar: Raise priority of the receiver thread.  In a
 loopback test, catching the returned data is higher priority than sending new
 data

---
 apps/examples/i2schar/i2schar_main.c | 59 +++++++++++++++++++++++++-----------
 1 file changed, 41 insertions(+), 18 deletions(-)

(limited to 'apps/examples/i2schar/i2schar_main.c')

diff --git a/apps/examples/i2schar/i2schar_main.c b/apps/examples/i2schar/i2schar_main.c
index 524a27550..01ca7fd15 100644
--- a/apps/examples/i2schar/i2schar_main.c
+++ b/apps/examples/i2schar/i2schar_main.c
@@ -245,6 +245,9 @@ int i2schar_main(int argc, char *argv[])
 #endif
 #ifdef CONFIG_EXAMPLES_I2SCHAR_RX
   pthread_t receiver;
+#endif
+#if defined(CONFIG_EXAMPLES_I2SCHAR_RX) & defined(CONFIG_EXAMPLES_I2SCHAR_TX)
+  struct sched_param param;
 #endif
   int ret;
 
@@ -286,46 +289,66 @@ int i2schar_main(int argc, char *argv[])
 #endif
 
   sched_lock();
+#ifdef CONFIG_EXAMPLES_I2SCHAR_RX
+  /* Start the receiver thread */
+
+  message("i2schar_main: Start receiver thread\n");
+  pthread_attr_init(&attr);
+
 #ifdef CONFIG_EXAMPLES_I2SCHAR_TX
-  /* Start the transmitter thread */
+  /* Bump the receiver priority from the default so that it will be above
+   * the priority of transmitter.  This is important if a loopback test is
+   * being performed; it improves the changes that a receiving audio buffer
+   * is in place for each transmission.
+    */
+
+  (void)pthread_attr_getschedparam(&attr, &param);
+  param.sched_priority++;
+  (void)pthread_attr_setschedparam(&attr, &param);
+#endif
 
-  message("i2schar_main: Start transmitter thread\n");
+  /* Set the receiver stack size */
 
-  pthread_attr_init(&attr);
-  (void)pthread_attr_setstacksize(&attr, CONFIG_EXAMPLES_I2SCHAR_TXSTACKSIZE);
+  (void)pthread_attr_setstacksize(&attr, CONFIG_EXAMPLES_I2SCHAR_RXSTACKSIZE);
 
-  ret = pthread_create(&transmitter, &attr, i2schar_transmitter, NULL);
+  /* Start the receiver */
+
+  ret = pthread_create(&receiver, &attr, i2schar_receiver, NULL);
   if (ret != OK)
     {
       sched_unlock();
-      message("i2schar_main: ERROR: failed to Start transmitter thread: %d\n", ret);
+      message("i2schar_main: ERROR: failed to Start receiver thread: %d\n", ret);
       return EXIT_FAILURE;
     }
 
-   pthread_setname_np(transmitter, "transmitter");
+   pthread_setname_np(receiver, "receiver");
 #endif
 
-#ifdef CONFIG_EXAMPLES_I2SCHAR_RX
-  /* Start the receiver thread */
-
-  message("i2schar_main: Start receiver thread\n");
+#ifdef CONFIG_EXAMPLES_I2SCHAR_TX
+  /* Start the transmitter thread */
 
+  message("i2schar_main: Start transmitter thread\n");
   pthread_attr_init(&attr);
-  (void)pthread_attr_setstacksize(&attr, CONFIG_EXAMPLES_I2SCHAR_RXSTACKSIZE);
 
-  ret = pthread_create(&receiver, &attr, i2schar_receiver, NULL);
+  /* Set the transmitter stack size */
+
+  (void)pthread_attr_setstacksize(&attr, CONFIG_EXAMPLES_I2SCHAR_TXSTACKSIZE);
+
+  /* Start the transmitter */
+
+  ret = pthread_create(&transmitter, &attr, i2schar_transmitter, NULL);
   if (ret != OK)
     {
       sched_unlock();
-      message("i2schar_main: ERROR: failed to Start receiver thread: %d\n", ret);
-#ifdef CONFIG_EXAMPLES_I2SCHAR_TX
-      message("i2schar_main: Waiting for the transmitter thread\n");
-      (void)pthread_join(transmitter, &result);
+      message("i2schar_main: ERROR: failed to Start transmitter thread: %d\n", ret);
+#ifdef CONFIG_EXAMPLES_I2SCHAR_RX
+      message("i2schar_main: Waiting for the receiver thread\n");
+      (void)pthread_join(receiver, &result);
 #endif
       return EXIT_FAILURE;
     }
 
-   pthread_setname_np(transmitter, "receiver");
+   pthread_setname_np(transmitter, "transmitter");
 #endif
 
    sched_unlock();
-- 
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