V4L2_MEMORY_USERPTR support on DM6446

Hi,

What about VIDIOC_REQBUFS? Is it returning successfully? How are you allocating for USER_PTR buffers? Are you using CMEM to allocate USER_PTR buffers?

Please provide details.

You can use this application about using USER_PTR(cmem).

Yes, VIDIOC_REQBUFS returns successfully, but I was not using CMEM, I was using memalign() to allocate the USER_PTR buffers. Isn't this correct? Can I only use CMEM?

Looks like v4l2 drivers don't support buffers allocated through memalign().

I've just modified my code to support CMEM and tried it. Unfortunately, still no success.

Basically, at startup I create 3 buffers for capturing, in this way:

int allocate_user_buffers(void)
{
    void *pool;
    int i;
    unsigned int buf_size = NUM_PIXELS*2; // 16bit  D1 resolution

    CMEM_AllocParams  alloc_params;
    printf("calling cmem utilities for allocating frame buffers\n");
    CMEM_init();

    alloc_params.type = CMEM_POOL;
    alloc_params.flags = CMEM_NONCACHED;
    alloc_params.alignment = 32;
    pool = CMEM_allocPool(0, &alloc_params);

    if (NULL == pool) {
        printf("Failed to allocate cmem pool\n");
        return -1;
    }
    printf("Allocating capture buffers :buf size = %d \n", buf_size);
   
    for (i=0; i < NUM_CAP_BUFS; i++) {
        capture_buffers[i].user_addr = CMEM_alloc(buf_size, &alloc_params);
        if (capture_buffers[i].user_addr) {
            capture_buffers[i].phy_addr = CMEM_getPhys(capture_buffers[i].user_addr);
            if (0 == capture_buffers[i].phy_addr) {
                printf("Failed to get phy cmem buffer address\n");
                return -1;
            }
        } else {
            printf("Failed to allocate cmem buffer\n");
            return -1;
        }
        printf("Got %p from CMEM, phy = %p\n", capture_buffers[i].user_addr, (void *)capture_buffers[i].phy_addr);
    }

    return 0;
}

This is correctly executed, as reported in the following console output:

calling cmem utilities for allocating frame buffers
Allocating capture buffers :buf size = 829440
Got 0x40f94000 from CMEM, phy = 0x87bc6000
Got 0x4105f000 from CMEM, phy = 0x87afb000
Got 0x4112a000 from CMEM, phy = 0x87a30000

Once again, the app fails when performing VIDIOC_QBUF in the following code fragment:

   for( numBufs = 0; numBufs < req.count; numBufs++ )
   {
        CLEAR( buf );
        
       buf.type   = V4L2_BUF_TYPE_VIDEO_CAPTURE;
       buf.memory = V4L2_MEMORY_USERPTR;
       buf.index  = numBufs;
      buf.length = 829440;
      buf.m.userptr = (unsigned long)buffersPtr[numBufs].user_addr;

      /*  Enqueue all of the allocated buffers to be available for capture */
      ret = ioctl( captureFd, VIDIOC_QBUF, &buf );
      if( ret  == -1 )
      {
          if(errno == EINVAL)
              printf("problem with buffer: length %d start %d index %d \n",buf.length,buf.m.userptr,buf.index);
         ERR( "VIODIOC_QBUF failed on file descriptor %d\n", captureFd );
          failure_procedure();                              //      macro defined at top of this function
      }
   }   

The output reports some info about the buffer involved in the failure, which I report here:

length 829440 start 1090076672 index 0

I don't know whether the start address is not valid, or there is a bug somewhere else, or if the DM6446 does not support USER_PTR. Any idea?

Looks like problem is different. Are you sure buf.m.userptr is prperly set. Also what is the height and width of the image you are capturing. Whatever you set during set_format should match with buf.length.