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 #include <unistd.h> 27 28 #ifndef FBIO_WAITFORVSYNC 29 #define FBIO_WAITFORVSYNC _IOW('F', 0x20, __u32) 30 #endif 31 32 int main(int argc, char** argv) { 33 int fd = open("/dev/graphics/fb0", O_RDWR); 34 if (fd >= 0) { 35 do { 36 uint32_t crt = 0; 37 int err = ioctl(fd, FBIO_WAITFORVSYNC, &crt); 38 if (err < 0) { 39 printf("FBIO_WAITFORVSYNC error: %s\n", strerror(errno)); 40 break; 41 } 42 } while(1); 43 close(fd); 44 } 45 return 0; 46 } 47
