test/debug/testvblank.c

   1
   2 /*
   3  * cc testvblank.c -o ~/bin/testvblank -I/usr/src/sys/dev/drm/include
   4  *
   5  * Should print one 'x' every 10 vblanks (6/sec @ 60Hz, 3/sec @ 30Hz).
   6  * Uses DRM ioctl.
   7  */
   8 #include <sys/types.h>
   9 #include <sys/ioctl.h>
  10 #include <sys/file.h>
  11 #include <uapi_drm/drm.h>
  12 #include <stdio.h>
  13 #include <string.h>
  14 #include <unistd.h>
  15
  16 int
  17 main(int ac, char **av)
  18 {
  19     union drm_wait_vblank vblank;
  20     int fd;
  21
  22     fd = open("/dev/dri/card0", O_RDWR);
  23     printf("should print one 'x' every 10 vblanks\n");
  24     for (;;) {
  25         bzero(&vblank, sizeof(vblank));
  26         vblank.request.type = _DRM_VBLANK_RELATIVE;
  27         vblank.request.sequence = 10;
  28
  29         if (ioctl(fd, DRM_IOCTL_WAIT_VBLANK, &vblank) < 0)
  30                 perror("ioctl");
  31         write(1, "x", 1);
  32     }
  33
  34     return 0;
  35 }