/*
** Test program for channel change priority levels: The program expects
** a numerical priority level on the command line.  First it will print
** the current maximum prio level (>= 1 since it includes itself at the
** default level) then change it's own level to the one given on the
** command line and attempt a channel change and report if it succeeds
** or fails.  After that the program sleeps for 20 seconds to allow to
** start it a second time in parallel at a different priority level.
**
** Author: Tom Zoerner (tomzo at nefkom net), June 14th 2003
**         http://nxtvepg.sourceforge.net/v4l2
*/
#include <stdio.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <linux/videodev.h>

#define DEVICE_PATH "/dev/vbi"

/* videodev2.h extensions */
enum v4l2_chn_prio {
	V4L2_CHN_PRIO_BACKGROUND,
	V4L2_CHN_PRIO_INTERACTIVE,
	V4L2_CHN_PRIO_DEFAULT = V4L2_CHN_PRIO_INTERACTIVE,
	V4L2_CHN_PRIO_RADIO   = V4L2_CHN_PRIO_INTERACTIVE,
	V4L2_CHN_PRIO_RECORD,
	V4L2_CHN_PRIO_EXCL,
	V4L2_CHN_PRIO_COUNT
};

#define BASE_VIDIOCPRIVATE	192		/* 192-255 are private */
#define VIDIOC_G_CHNPRIO        _IOR('V' , BASE_VIDIOCPRIVATE+10, enum v4l2_chn_prio)
#define VIDIOC_S_CHNPRIO        _IOW('V' , BASE_VIDIOCPRIVATE+11, enum v4l2_chn_prio)

int main( int argc, char ** argv )
{
   char * p_num_end;
   enum v4l2_chn_prio prio;
   enum v4l2_chn_prio max_prio;
   int    fd;

   if (argc == 2)
   {
      prio = strtol(argv[1], &p_num_end, 0);

      printf("Opening %s\n", DEVICE_PATH);
      fd = open(DEVICE_PATH, O_RDWR);
      if (fd != -1)
      {
         if (ioctl(fd, VIDIOC_G_CHNPRIO, &max_prio) == 0)
            printf("Current max. priority level = %d (via G_CHNPRIO)\n", (int)max_prio);
         else
            fprintf(stderr, "ioctl VIDIOC_S_CHNPRIO(%d): %d: %s\n", prio, errno, strerror(errno));

         printf("Setting my priority level to %d (via S_CHNPRIO)\n", (int)prio);
         if (ioctl(fd, VIDIOC_S_CHNPRIO, &prio) == 0)
         {
            struct video_channel vchan;

            if (ioctl(fd, VIDIOC_G_CHNPRIO, &max_prio) == 0)
               printf("New max. priority level = %d (via G_CHNPRIO)\n", (int)max_prio);
            else
               fprintf(stderr, "ioctl VIDIOC_S_CHNPRIO(%d): %d: %s\n", prio, errno, strerror(errno));

            memset(&vchan, 0, sizeof(vchan));
            if (ioctl(fd, VIDIOCGCHAN, &vchan) == 0)
            {
               if (ioctl(fd, VIDIOCSCHAN, &vchan) == 0)
                  printf("Channel change successful.\n", (int)prio);
               else if (errno == EBUSY)
                  printf("Channel change failed: device busy (at higher priority)\n", (int)prio);
               else
                  perror("VIDIOCSCHAN");
            }
            printf("Sleeping 20 secs now...\n");
            printf("Start the test in parallel with a different priority.\n");
            sleep(20);
         }
         else
            fprintf(stderr, "ioctl VIDIOC_S_CHNPRIO(%d): %d: %s\n", (int)prio, errno, strerror(errno));

         close(fd);
      }
      else
         perror("open " DEVICE_PATH);
   }
   else
      fprintf(stderr, "Usage: %s <prio>\n", argv[0]);

   return 0;
}