Hi all,
I am running the attached demo example on DM355 leopard board but i am getting the following output.
Please tell me where the output is getting stuck,it is somewhere in the kernel.
[42949429.590000] Unable to handle kernel NULL pointer dereference at virtual address 00000030
[42949429.600000] pgd = c66b4000
[42949429.600000] [00000030] *pgd=863eb031, *pte=00000000, *ppte=00000000
[42949429.610000] Internal error: Oops: 17 [#1] PREEMPT
[42949429.610000] Modules linked in: dm350mmap cmemk
[42949429.610000] CPU: 0 Not tainted (2.6.29-ridgerun-davinci1 #1)
[42949429.610000] PC is at v4l2_int_ioctl_1+0x14/0x38
[42949429.610000] LR is at vpfe_open+0x114/0x27c
[42949429.610000] pc : [<c014de90>] lr : [<c01593f8>] psr: 60000013
[42949429.610000] sp : c60a1dd8 ip : c60a1df0 fp : c60a1dec
[42949429.610000] r10: c60709c0 r9 : c60a0000 r8 : 00000001
[42949429.610000] r7 : c60709c0 r6 : c6366f00 r5 : c66f2424 r4 : 00000000
[42949429.610000] r3 : c0309da0 r2 : c66f2424 r1 : 000003ec r0 : 00000000
[42949429.610000] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
[42949429.610000] Control: 0005317f Table: 866b4000 DAC: 00000015
[42949429.610000] Process a.out (pid: 333, stack limit = 0xc60a0268)
[42949429.610000] Stack: (0xc60a1dd8 to 0xc60a2000)
[42949429.610000] 1dc0: 00000000 c66f2400
[42949429.610000] 1de0: c60a1e14 c60a1df0 c01593f8 c014de8c c0137168 c66f7400 c66f7408 c60709c0
[42949429.610000] 1e00: c50420f8 00000000 c60a1e34 c60a1e18 c0148f38 c01592f4 c50420f8 c60a0000
[42949429.610000] 1e20: 00000000 c6078260 c60a1e64 c60a1e38 c008dbb4 c0148ec8 c50420f8 00000000
[42949429.610000] 1e40: c60709c0 c50420f8 00000000 c008d9d4 c600d2a0 c50465d8 c60a1e8c c60a1e68
[42949429.610000] 1e60: c00888dc c008d9e4 c60709c0 c6071d40 c66bf000 00000803 ffffff9c 40024000
[42949429.610000] 1e80: c60a1eac c60a1e90 c0089ac4 c008875c 00000000 c6071d40 00000000 c60a1ee0
[42949429.610000] 1ea0: c60a1f6c c60a1eb0 c00961b4 c0089a88 00000803 c0051ce4 00000000 000000aa
[42949429.610000] 1ec0: 400cf000 00000000 00000000 00000802 c60a0000 00000026 c0307cc4 00000000
[42949429.610000] 1ee0: c600d2a0 c50465d8 00000000 40024000 c60a1fac 00000101 00000001 00000000
[42949429.610000] 1f00: 00000000 0e1506b8 c66b5000 00000000 00000000 ffffffff 00000200 400cf000
[42949429.610000] 1f20: c60a1f3c 00000803 00000000 c60709c0 00000000 00000000 c60a1f6c c60a1f48
[42949429.610000] 1f40: c009f694 00000802 00000003 c66bf000 00000000 ffffff9c c60a0000 40024000
[42949429.610000] 1f60: c60a1f94 c60a1f70 c00886ac c0095e48 00000000 40023db0 00000000 00000000
[42949429.610000] 1f80: 00000005 c0025fa4 c60a1fa4 c60a1f98 c0088728 c0088660 00000000 c60a1fa8
[42949429.610000] 1fa0: c0025e20 c0088714 40023db0 00000000 0000a374 00000802 00000000 0000a374
[42949429.610000] 1fc0: 40023db0 00000000 00000000 00000005 00000000 00000000 40024000 be8f5cf4
[42949429.610000] 1fe0: 00000000 be8f5c78 00009c64 400cf01c 60000010 0000a374 ebfefcfb 9c3d136e
[42949429.610000] Backtrace:
[42949429.610000] [<c014de7c>] (v4l2_int_ioctl_1+0x0/0x38) from [<c01593f8>] (vpfe_open+0x114/0x27c)
[42949429.610000] r5:c66f2400 r4:00000000
[42949429.610000] [<c01592e4>] (vpfe_open+0x0/0x27c) from [<c0148f38>] (v4l2_open+0x80/0xa0)
[42949429.610000] r8:00000000 r7:c50420f8 r6:c60709c0 r5:c66f7408 r4:c66f7400
[42949429.610000] [<c0148eb8>] (v4l2_open+0x0/0xa0) from [<c008dbb4>] (chrdev_open+0x1e0/0x200)
[42949429.610000] r6:c6078260 r5:00000000 r4:c60a0000
[42949429.610000] [<c008d9d4>] (chrdev_open+0x0/0x200) from [<c00888dc>] (__dentry_open+0x190/0x2ac)
[42949429.610000] [<c008874c>] (__dentry_open+0x0/0x2ac) from [<c0089ac4>] (nameidata_to_filp+0x4c/0x64)
[42949429.610000] [<c0089a78>] (nameidata_to_filp+0x0/0x64) from [<c00961b4>] (do_filp_open+0x37c/0x73c)
[42949429.610000] r5:c60a1ee0 r4:00000000
[42949429.610000] [<c0095e38>] (do_filp_open+0x0/0x73c) from [<c00886ac>] (do_sys_open+0x5c/0xa0)
[42949429.610000] [<c0088650>] (do_sys_open+0x0/0xa0) from [<c0088728>] (sys_open+0x24/0x28)
[42949429.610000] r8:c0025fa4 r7:00000005 r6:00000000 r5:00000000 r4:40023db0
[42949429.610000] [<c0088704>] (sys_open+0x0/0x28) from [<c0025e20>] (ret_fast_syscall+0x0/0x2c)
[42949429.610000] Code: e92dd830 e24cb004 e1a04000 e1a05002 (e5900030)
[42949429.960000] ---[ end trace 70ffc750b2ccd527 ]---
Segmentation fault
Following is the c file that i am running:
/*
* V4L2 video capture example
*
* This program can be used and distributed without restrictions.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <getopt.h> /* getopt_long() */
#include <fcntl.h> /* low-level i/o */
#include <unistd.h>
#include <errno.h>
#include <malloc.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <asm/types.h> /* for videodev2.h */
#include <linux/videodev2.h>
#define CLEAR(x) memset (&(x), 0, sizeof (x))
typedef enum {
IO_METHOD_READ,
IO_METHOD_MMAP,
IO_METHOD_USERPTR,
} io_method;
struct buffer {
void * start;
size_t length;
};
static char * dev_name = NULL;
static io_method io = IO_METHOD_MMAP;
static int fd = -1;
struct buffer * buffers = NULL;
static unsigned int n_buffers = 0;
static void
errno_exit (const char * s)
{
fprintf (stderr, "%s error %d, %s\n",
s, errno, strerror (errno));
exit (EXIT_FAILURE);
}
static int
xioctl (int fd,
int request,
void * arg)
{
int r;
do r = ioctl (fd, request, arg);
while (-1 == r && EINTR == errno);
return r;
}
static void
process_image (const void * p)
{
fputc ('.', stdout);
fflush (stdout);
}
static int
read_frame (void)
{
struct v4l2_buffer buf;
unsigned int i;
switch (io) {
case IO_METHOD_READ:
if (-1 == read (fd, buffers[0].start, buffers[0].length)) {
switch (errno) {
case EAGAIN:
return 0;
case EIO:
/* Could ignore EIO, see spec. */
/* fall through */
default:
errno_exit ("read");
}
}
process_image (buffers[0].start);
break;
case IO_METHOD_MMAP:
CLEAR (buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
if (-1 == xioctl (fd, VIDIOC_DQBUF, &buf)) {
switch (errno) {
case EAGAIN:
return 0;
case EIO:
/* Could ignore EIO, see spec. */
/* fall through */
default:
errno_exit ("VIDIOC_DQBUF");
}
}
assert (buf.index < n_buffers);
process_image (buffers[buf.index].start);
if (-1 == xioctl (fd, VIDIOC_QBUF, &buf))
errno_exit ("VIDIOC_QBUF");
break;
case IO_METHOD_USERPTR:
CLEAR (buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_USERPTR;
if (-1 == xioctl (fd, VIDIOC_DQBUF, &buf)) {
switch (errno) {
case EAGAIN:
return 0;
case EIO:
/* Could ignore EIO, see spec. */
/* fall through */
default:
errno_exit ("VIDIOC_DQBUF");
}
}
for (i = 0; i < n_buffers; ++i)
if (buf.m.userptr == (unsigned long) buffers[i].start
&& buf.length == buffers[i].length)
break;
assert (i < n_buffers);
process_image ((void *) buf.m.userptr);
if (-1 == xioctl (fd, VIDIOC_QBUF, &buf))
errno_exit ("VIDIOC_QBUF");
break;
}
return 1;
}
static void
mainloop (void)
{
unsigned int count;
count = 100;
while (count-- > 0) {
for (;;) {
fd_set fds;
struct timeval tv;
int r;
FD_ZERO (&fds);
FD_SET (fd, &fds);
/* Timeout. */
tv.tv_sec = 2;
tv.tv_usec = 0;
r = select (fd + 1, &fds, NULL, NULL, &tv);
if (-1 == r) {
if (EINTR == errno)
continue;
errno_exit ("select");
}
if (0 == r) {
fprintf (stderr, "select timeout\n");
exit (EXIT_FAILURE);
}
if (read_frame ())
break;
/* EAGAIN - continue select loop. */
}
}
}
static void
stop_capturing (void)
{
enum v4l2_buf_type type;
switch (io) {
case IO_METHOD_READ:
/* Nothing to do. */
break;
case IO_METHOD_MMAP:
case IO_METHOD_USERPTR:
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (-1 == xioctl (fd, VIDIOC_STREAMOFF, &type))
errno_exit ("VIDIOC_STREAMOFF");
break;
}
}
static void
start_capturing (void)
{
unsigned int i;
enum v4l2_buf_type type;
switch (io) {
case IO_METHOD_READ:
/* Nothing to do. */
break;
case IO_METHOD_MMAP:
for (i = 0; i < n_buffers; ++i) {
struct v4l2_buffer buf;
CLEAR (buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = i;
if (-1 == xioctl (fd, VIDIOC_QBUF, &buf))
errno_exit ("VIDIOC_QBUF");
}
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (-1 == xioctl (fd, VIDIOC_STREAMON, &type))
errno_exit ("VIDIOC_STREAMON");
break;
case IO_METHOD_USERPTR:
for (i = 0; i < n_buffers; ++i) {
struct v4l2_buffer buf;
CLEAR (buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_USERPTR;
buf.index = i;
buf.m.userptr = (unsigned long) buffers[i].start;
buf.length = buffers[i].length;
if (-1 == xioctl (fd, VIDIOC_QBUF, &buf))
errno_exit ("VIDIOC_QBUF");
}
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (-1 == xioctl (fd, VIDIOC_STREAMON, &type))
errno_exit ("VIDIOC_STREAMON");
break;
}
}
static void
uninit_device (void)
{
unsigned int i;
switch (io) {
case IO_METHOD_READ:
free (buffers[0].start);
break;
case IO_METHOD_MMAP:
for (i = 0; i < n_buffers; ++i)
if (-1 == munmap (buffers[i].start, buffers[i].length))
errno_exit ("munmap");
break;
case IO_METHOD_USERPTR:
for (i = 0; i < n_buffers; ++i)
free (buffers[i].start);
break;
}
free (buffers);
}
static void
init_read (unsigned int buffer_size)
{
buffers = calloc (1, sizeof (*buffers));
if (!buffers) {
fprintf (stderr, "Out of memory\n");
exit (EXIT_FAILURE);
}
buffers[0].length = buffer_size;
buffers[0].start = malloc (buffer_size);
if (!buffers[0].start) {
fprintf (stderr, "Out of memory\n");
exit (EXIT_FAILURE);
}
}
static void
init_mmap (void)
{
struct v4l2_requestbuffers req;
CLEAR (req);
req.count = 4;
req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
req.memory = V4L2_MEMORY_MMAP;
if (-1 == xioctl (fd, VIDIOC_REQBUFS, &req)) {
if (EINVAL == errno) {
fprintf (stderr, "%s does not support "
"memory mapping\n", dev_name);
exit (EXIT_FAILURE);
} else {
errno_exit ("VIDIOC_REQBUFS");
}
}
if (req.count < 2) {
fprintf (stderr, "Insufficient buffer memory on %s\n",
dev_name);
exit (EXIT_FAILURE);
}
buffers = calloc (req.count, sizeof (*buffers));
if (!buffers) {
fprintf (stderr, "Out of memory\n");
exit (EXIT_FAILURE);
}
for (n_buffers = 0; n_buffers < req.count; ++n_buffers) {
struct v4l2_buffer buf;
CLEAR (buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = n_buffers;
if (-1 == xioctl (fd, VIDIOC_QUERYBUF, &buf))
errno_exit ("VIDIOC_QUERYBUF");
buffers[n_buffers].length = buf.length;
buffers[n_buffers].start =
mmap (NULL /* start anywhere */,
buf.length,
PROT_READ | PROT_WRITE /* required */,
MAP_SHARED /* recommended */,
fd, buf.m.offset);
if (MAP_FAILED == buffers[n_buffers].start)
errno_exit ("mmap");
}
}
static void
init_userp (unsigned int buffer_size)
{
struct v4l2_requestbuffers req;
unsigned int page_size;
page_size = getpagesize ();
buffer_size = (buffer_size + page_size - 1) & ~(page_size - 1);
CLEAR (req);
req.count = 4;
req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
req.memory = V4L2_MEMORY_USERPTR;
if (-1 == xioctl (fd, VIDIOC_REQBUFS, &req)) {
if (EINVAL == errno) {
fprintf (stderr, "%s does not support "
"user pointer i/o\n", dev_name);
exit (EXIT_FAILURE);
} else {
errno_exit ("VIDIOC_REQBUFS");
}
}
buffers = calloc (4, sizeof (*buffers));
if (!buffers) {
fprintf (stderr, "Out of memory\n");
exit (EXIT_FAILURE);
}
for (n_buffers = 0; n_buffers < 4; ++n_buffers) {
buffers[n_buffers].length = buffer_size;
buffers[n_buffers].start = memalign (/* boundary */ page_size,
buffer_size);
if (!buffers[n_buffers].start) {
fprintf (stderr, "Out of memory\n");
exit (EXIT_FAILURE);
}
}
}
static void
init_device (void)
{
struct v4l2_capability cap;
struct v4l2_cropcap cropcap;
struct v4l2_crop crop;
struct v4l2_format fmt;
unsigned int min;
if (-1 == xioctl (fd, VIDIOC_QUERYCAP, &cap)) {
if (EINVAL == errno) {
fprintf (stderr, "%s is no V4L2 device\n",
dev_name);
exit (EXIT_FAILURE);
} else {
errno_exit ("VIDIOC_QUERYCAP");
}
}
if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
fprintf (stderr, "%s is no video capture device\n",
dev_name);
exit (EXIT_FAILURE);
}
switch (io) {
case IO_METHOD_READ:
if (!(cap.capabilities & V4L2_CAP_READWRITE)) {
fprintf (stderr, "%s does not support read i/o\n",
dev_name);
exit (EXIT_FAILURE);
}
break;
case IO_METHOD_MMAP:
case IO_METHOD_USERPTR:
if (!(cap.capabilities & V4L2_CAP_STREAMING)) {
fprintf (stderr, "%s does not support streaming i/o\n",
dev_name);
exit (EXIT_FAILURE);
}
break;
}
/* Select video input, video standard and tune here. */
CLEAR (cropcap);
cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (0 == xioctl (fd, VIDIOC_CROPCAP, &cropcap)) {
crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
crop.c = cropcap.defrect; /* reset to default */
if (-1 == xioctl (fd, VIDIOC_S_CROP, &crop)) {
switch (errno) {
case EINVAL:
/* Cropping not supported. */
break;
default:
/* Errors ignored. */
break;
}
}
} else {
/* Errors ignored. */
}
CLEAR (fmt);
fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
fmt.fmt.pix.width = 640;
fmt.fmt.pix.height = 480;
fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;
if (-1 == xioctl (fd, VIDIOC_S_FMT, &fmt))
errno_exit ("VIDIOC_S_FMT");
/* Note VIDIOC_S_FMT may change width and height. */
/* Buggy driver paranoia. */
min = fmt.fmt.pix.width * 2;
if (fmt.fmt.pix.bytesperline < min)
fmt.fmt.pix.bytesperline = min;
min = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height;
if (fmt.fmt.pix.sizeimage < min)
fmt.fmt.pix.sizeimage = min;
switch (io) {
case IO_METHOD_READ:
init_read (fmt.fmt.pix.sizeimage);
break;
case IO_METHOD_MMAP:
init_mmap ();
break;
case IO_METHOD_USERPTR:
init_userp (fmt.fmt.pix.sizeimage);
break;
}
}
static void
close_device (void)
{
if (-1 == close (fd))
errno_exit ("close");
fd = -1;
}
static void
open_device (void)
{
struct stat st;
if (-1 == stat (dev_name, &st)) {
fprintf (stderr, "Cannot identify '%s': %d, %s\n",
dev_name, errno, strerror (errno));
exit (EXIT_FAILURE);
}
if (!S_ISCHR (st.st_mode)) {
fprintf (stderr, "%s is no device\n", dev_name);
exit (EXIT_FAILURE);
}
fd = open (dev_name, O_RDWR /* required */ | O_NONBLOCK, 0);
if (-1 == fd) {
fprintf (stderr, "Cannot open '%s': %d, %s\n",
dev_name, errno, strerror (errno));
exit (EXIT_FAILURE);
}
}
static void
usage (FILE * fp,
int argc,
char ** argv)
{
fprintf (fp,
"Usage: %s [options]\n\n"
"Options:\n"
"-d | --device name Video device name [/dev/video]\n"
"-h | --help Print this message\n"
"-m | --mmap Use memory mapped buffers\n"
"-r | --read Use read() calls\n"
"-u | --userp Use application allocated buffers\n"
"",
argv[0]);
}
static const char short_options [] = "d:hmru";
static const struct option
long_options [] = {
{ "device", required_argument, NULL, 'd' },
{ "help", no_argument, NULL, 'h' },
{ "mmap", no_argument, NULL, 'm' },
{ "read", no_argument, NULL, 'r' },
{ "userp", no_argument, NULL, 'u' },
{ 0, 0, 0, 0 }
};
int
main (int argc,
char ** argv)
{
dev_name = "/dev/video0";
for (;;) {
int index;
int c;
c = getopt_long (argc, argv,
short_options, long_options,
&index);
if (-1 == c)
break;
switch (c) {
case 0: /* getopt_long() flag */
break;
case 'd':
dev_name = optarg;
break;
case 'h':
usage (stdout, argc, argv);
exit (EXIT_SUCCESS);
case 'm':
io = IO_METHOD_MMAP;
break;
case 'r':
io = IO_METHOD_READ;
break;
case 'u':
io = IO_METHOD_USERPTR;
break;
default:
usage (stderr, argc, argv);
exit (EXIT_FAILURE);
}
}
open_device ();
printf("Device open success\n");
init_device ();
printf("Device init success\n");
printf("Before start capturing\n");
start_capturing ();
printf("After start capturing\n");
mainloop ();
printf("Before stop capturing\n");
stop_capturing ();
printf("After stop capturing\n");
uninit_device ();
close_device ();
exit (EXIT_SUCCESS);
return 0;
}
Thanks and Regards,
Mayank
