[Forwarding from a coder who wants to be anonymous] The documentation at: http://v4l2spec.bytesex.org/spec-single/v4l2.html#VIDIOC-REQBUFS says that the VIDIOC_REQBUFS ioctl(), used to initiate memory mapping or user pointer i/o on V4L2 devices, returns a 0 upon success, or a -1 on error, and sets errno to either EBUSY or EINVAL. The code, however, does not follow this logic. In /usr/src/linux/drivers/media/video/videobuf-core.c, in the function int videobuf_reqbufs(struct videobuf_queue *q, \ struct v4l2_requestbuffers *req); If an error occours, "return -EINVAL" is called. If an error does not occour, execution reaches the following statement: retval = __videobuf_mmap_setup(q, count, size, req->memory); followed by: req->count = retval; and: return retval; So, the value being returned, upon success, is the value returned from the call to __videobuf_mmap_setup(). Looking inside the code for this function, the buffers are setup inside a for() loop, and the last value of "i" used as a counter for that loop is returned. In other words, the buffers allocated count is returned. So, is the documentation wrong ? or is the code wrong ? _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
