mfc: fix compilation with newer GLib versions

that don't include pthread.h any more from public headers.
We could just fix this by including pthread.h ourselves,
but we may just as well use atomic ops for this and
simplify the code a little.

https://bugzilla.gnome.org/show_bug.cgi?id=693322

diff --git a/sys/mfc/fimc/fimc.c b/sys/mfc/fimc/fimc.c
index b8334ed..64df868 100644 (file)
--- a/sys/mfc/fimc/fimc.c
+++ b/sys/mfc/fimc/fimc.c
@@ -49,6 +49,9 @@
 #include <string.h>
 #include <linux/videodev2.h>
 
+/* for g_atomic_* */
+#include <glib.h>
+
 /* For logging */
 #include <gst/gst.h>
 GST_DEBUG_CATEGORY (fimc_debug);
@@ -86,8 +89,7 @@ struct _Fimc
 
 #define FIMC_PATH "/dev/video4"
 
-static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
-static int fimc_in_use;
+static volatile int fimc_in_use;
 
 void
 fimc_init_debug (void)
@@ -100,14 +102,10 @@ fimc_new (void)
 {
   Fimc *fimc;
 
-  pthread_mutex_lock (&mutex);
-  if (fimc_in_use) {
+  if (!g_atomic_int_compare_and_exchange (&fimc_in_use, FALSE, TRUE)) {
     GST_ERROR ("Rejected because FIMC is already in use");
-    pthread_mutex_unlock (&mutex);
     return NULL;
   }
-  fimc_in_use = 1;
-  pthread_mutex_unlock (&mutex);
 
   fimc = calloc (1, sizeof (Fimc));
 
@@ -148,9 +146,7 @@ fimc_free (Fimc * fimc)
   if (fimc->fd != -1)
     close (fimc->fd);
 
-  pthread_mutex_lock (&mutex);
-  fimc_in_use = 0;
-  pthread_mutex_unlock (&mutex);
+  g_atomic_int_set (&fimc_in_use, FALSE);
   free (fimc);
 }