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List:       linux-video
Subject:    V4l1-compat SAA7134 EBUSY issue.
From:       Rob Kramer <robk () starhub ! net ! sg>
Date:       2005-12-21 14:36:16
Message-ID: 200512212236.16343.robk () starhub ! net ! sg
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Hi there,

If I run the test program below on my FC4 standard kernel (2.6.14-1.1653_FC4) 
with saa7134, I get the following output:

[root@epia ~]# ./testcapture
Capture 1
Capture 2
VIDIOCGMBUF, errno: 16, Device or resource busy

It seems this is because the videobuf is still in streaming mode. Is my test 
supposed to work at all, i.e. should I be able to do a VIDIOCGMBUF after 
VIDIOCSYNC? If I cheat and insert a v4l2 VIDIOC_STREAMOFF after the CSYNC, it 
works (but the legacy application I'm working on is v4l1).

Has anyone here seen this before?

Cheers!

    Rob


testcapture.c (never mind all the leaks etc.)
---------------------------------------
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <string.h>
#include <errno.h>
#include <linux/videodev.h>


void die (char *s)
{
    printf ("%s, errno: %d, %s\n", s, errno, strerror (errno));
    exit (1);
}

void testCapture (int fd)
{
    int frame = 0;
    unsigned char *buffer;
    struct video_mbuf vmbuf;
    struct video_mmap vmmap;

    if (ioctl (fd, VIDIOCGMBUF, &vmbuf) < 0)
        die ("VIDIOCGMBUF");

    buffer = mmap (0, vmbuf.size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);

    vmmap.width = 200;
    vmmap.height = 200;
    vmmap.format = 7;
    vmmap.frame = frame;

    if (ioctl (fd, VIDIOCMCAPTURE, &vmmap) < 0)
        die ("VIDIOCMCAPTURE");

    if (ioctl (fd, VIDIOCSYNC, &frame) < 0)
        die ("VIDIOCSYNC");

    munmap (buffer, vmbuf.size);
}


int main (char **argv, int argc)
{
    int fd = open ("/dev/video0", O_RDWR);

    printf ("Capture 1\n");
    testCapture (fd);

    printf ("Capture 2\n");
    testCapture (fd);

    close (fd);

    return 0;
}

-- 
I explode like a bomb. No-one is spared. 
My power is my mass times the speed of light squared.

    - MC Hawking

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