1 /*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <stdint.h>
18 #include <sys/types.h>
19
20 #include <fcntl.h>
21 #include <sys/ioctl.h>
22 #include <linux/fb.h>
23 #include <errno.h>
24 #include <string.h>
25 #include <stdio.h>
26
27 #ifndef FBIO_WAITFORVSYNC
28 #define FBIO_WAITFORVSYNC _IOW('F', 0x20, __u32)
29 #endif
30
main(int argc,char ** argv)31 int main(int argc, char** argv) {
32 int fd = open("/dev/graphics/fb0", O_RDWR);
33 if (fd >= 0) {
34 do {
35 uint32_t crt = 0;
36 int err = ioctl(fd, FBIO_WAITFORVSYNC, &crt);
37 if (err < 0) {
38 printf("FBIO_WAITFORVSYNC error: %s\n", strerror(errno));
39 break;
40 }
41 } while(1);
42 close(fd);
43 }
44 return 0;
45 }
46