Merge pull request #59 from gridpoint-com/fb0-timeout

Wait for upto 60s for /dev/fb0 to become available

c_src/device/cairo/cairo_fb.c

@@ -2,18 +2,21 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <linux/fb.h>
+#include <sched.h>
 #include <stdlib.h>
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <time.h>
 
 #include "cairo_ctx.h"
 #include "comms.h"
 #include "device.h"
 #include "fontstash.h"
 #include "scenic_ops.h"
 
+#define FB0_TIMEOUT 60 //seconds
 const char* device = "/dev/fb0";
 
 typedef struct {
@@ -95,7 +98,15 @@ int device_init(const device_opts_t* p_opts,
 
   p_info->v_ctx = p_ctx;
 
-  if ((g_cairo_fb.fd = open(device, O_RDWR)) == -1) {
+  time_t fb0_timer_start = time(NULL);
+  while ((time(NULL) - fb0_timer_start) < FB0_TIMEOUT) {
+    if ((g_cairo_fb.fd = open(device, O_RDWR)) != -1) {
+      break;
+    }
+    sched_yield();
+  }
+
+  if (g_cairo_fb.fd == -1) {
     log_error("Failed to open device %s: %s", device, strerror(errno));
     return -1;
   }