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uvc-gadget.c
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uvc-gadget.c
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/*
* UVC gadget test application
*
* Copyright (C) 2010 Ideas on board SPRL <laurent.pinchart@ideasonboard.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
*/
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/select.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <errno.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <linux/usb/ch9.h>
#include <linux/usb/video.h>
#include <linux/videodev2.h>
#include "uvc.h"
/* Enable debug prints. */
#undef ENABLE_BUFFER_DEBUG
#undef ENABLE_USB_REQUEST_DEBUG
#define CLEAR(x) memset(&(x), 0, sizeof(x))
#define max(a, b) (((a) > (b)) ? (a) : (b))
#define clamp(val, min, max) \
({ \
typeof(val) __val = (val); \
typeof(min) __min = (min); \
typeof(max) __max = (max); \
(void)(&__val == &__min); \
(void)(&__val == &__max); \
__val = __val < __min ? __min : __val; \
__val > __max ? __max : __val; \
})
#define ARRAY_SIZE(a) ((sizeof(a) / sizeof(a[0])))
#define pixfmtstr(x) (x) & 0xff, ((x) >> 8) & 0xff, ((x) >> 16) & 0xff, ((x) >> 24) & 0xff
/*
* The UVC webcam gadget kernel driver (g_webcam.ko) supports changing
* the Brightness attribute of the Processing Unit (PU). by default. If
* the underlying video capture device supports changing the Brightness
* attribute of the image being acquired (like the Virtual Video, VIVI
* driver), then we should route this UVC request to the respective
* video capture device.
*
* Incase, there is no actual video capture device associated with the
* UVC gadget and we wish to use this application as the final
* destination of the UVC specific requests then we should return
* pre-cooked (static) responses to GET_CUR(BRIGHTNESS) and
* SET_CUR(BRIGHTNESS) commands to keep command verifier test tools like
* UVC class specific test suite of USBCV, happy.
*
* Note that the values taken below are in sync with the VIVI driver and
* must be changed for your specific video capture device. These values
* also work well in case there in no actual video capture device.
*/
#define PU_BRIGHTNESS_MIN_VAL 0
#define PU_BRIGHTNESS_MAX_VAL 255
#define PU_BRIGHTNESS_STEP_SIZE 1
#define PU_BRIGHTNESS_DEFAULT_VAL 127
/* ---------------------------------------------------------------------------
* Generic stuff
*/
/* IO methods supported */
enum io_method {
IO_METHOD_MMAP,
IO_METHOD_USERPTR,
};
/* Buffer representing one video frame */
struct buffer {
struct v4l2_buffer buf;
void *start;
size_t length;
};
/* ---------------------------------------------------------------------------
* UVC specific stuff
*/
struct uvc_frame_info {
unsigned int width;
unsigned int height;
unsigned int intervals[8];
};
struct uvc_format_info {
unsigned int fcc;
const struct uvc_frame_info *frames;
};
static const struct uvc_frame_info uvc_frames_yuyv[] = {
{
640,
360,
{666666, 10000000, 50000000, 0},
},
{
1280,
720,
{50000000, 0},
},
{
0,
0,
{
0,
},
},
};
static const struct uvc_frame_info uvc_frames_mjpeg[] = {
{
640,
360,
{666666, 10000000, 50000000, 0},
},
{
1280,
720,
{50000000, 0},
},
{
0,
0,
{
0,
},
},
};
static const struct uvc_format_info uvc_formats[] = {
{V4L2_PIX_FMT_YUYV, uvc_frames_yuyv},
{V4L2_PIX_FMT_MJPEG, uvc_frames_mjpeg},
};
/* ---------------------------------------------------------------------------
* V4L2 and UVC device instances
*/
/* Represents a V4L2 based video capture device */
struct v4l2_device {
/* v4l2 device specific */
int v4l2_fd;
int is_streaming;
char *v4l2_devname;
/* v4l2 buffer specific */
enum io_method io;
struct buffer *mem;
unsigned int nbufs;
/* v4l2 buffer queue and dequeue counters */
unsigned long long int qbuf_count;
unsigned long long int dqbuf_count;
/* uvc device hook */
struct uvc_device *udev;
};
/* Represents a UVC based video output device */
struct uvc_device {
/* uvc device specific */
int uvc_fd;
int is_streaming;
int run_standalone;
char *uvc_devname;
/* uvc control request specific */
struct uvc_streaming_control probe;
struct uvc_streaming_control commit;
int control;
struct uvc_request_data request_error_code;
unsigned int brightness_val;
/* uvc buffer specific */
enum io_method io;
struct buffer *mem;
struct buffer *dummy_buf;
unsigned int nbufs;
unsigned int fcc;
unsigned int width;
unsigned int height;
unsigned int bulk;
uint8_t color;
unsigned int imgsize;
void *imgdata;
/* USB speed specific */
int mult;
int burst;
int maxpkt;
enum usb_device_speed speed;
/* uvc specific flags */
int first_buffer_queued;
int uvc_shutdown_requested;
/* uvc buffer queue and dequeue counters */
unsigned long long int qbuf_count;
unsigned long long int dqbuf_count;
/* v4l2 device hook */
struct v4l2_device *vdev;
};
/* forward declarations */
static int uvc_video_stream(struct uvc_device *dev, int enable);
/* ---------------------------------------------------------------------------
* V4L2 streaming related
*/
static int v4l2_uninit_device(struct v4l2_device *dev)
{
unsigned int i;
int ret;
switch (dev->io) {
case IO_METHOD_MMAP:
for (i = 0; i < dev->nbufs; ++i) {
ret = munmap(dev->mem[i].start, dev->mem[i].length);
if (ret < 0) {
printf("V4L2: munmap failed\n");
return ret;
}
}
free(dev->mem);
break;
case IO_METHOD_USERPTR:
default:
break;
}
return 0;
}
static int v4l2_reqbufs_mmap(struct v4l2_device *dev, int nbufs)
{
struct v4l2_requestbuffers req;
unsigned int i = 0;
int ret;
CLEAR(req);
req.count = nbufs;
req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
req.memory = V4L2_MEMORY_MMAP;
ret = ioctl(dev->v4l2_fd, VIDIOC_REQBUFS, &req);
if (ret < 0) {
if (ret == -EINVAL)
printf("V4L2: does not support memory mapping\n");
else
printf("V4L2: VIDIOC_REQBUFS error %s (%d).\n", strerror(errno), errno);
goto err;
}
if (!req.count)
return 0;
if (req.count < 2) {
printf("V4L2: Insufficient buffer memory.\n");
ret = -EINVAL;
goto err;
}
/* Map the buffers. */
dev->mem = calloc(req.count, sizeof dev->mem[0]);
if (!dev->mem) {
printf("V4L2: Out of memory\n");
ret = -ENOMEM;
goto err;
}
for (i = 0; i < req.count; ++i) {
memset(&dev->mem[i].buf, 0, sizeof(dev->mem[i].buf));
dev->mem[i].buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
dev->mem[i].buf.memory = V4L2_MEMORY_MMAP;
dev->mem[i].buf.index = i;
ret = ioctl(dev->v4l2_fd, VIDIOC_QUERYBUF, &(dev->mem[i].buf));
if (ret < 0) {
printf(
"V4L2: VIDIOC_QUERYBUF failed for buf %d: "
"%s (%d).\n",
i, strerror(errno), errno);
ret = -EINVAL;
goto err_free;
}
dev->mem[i].start =
mmap(NULL /* start anywhere */, dev->mem[i].buf.length, PROT_READ | PROT_WRITE /* required */,
MAP_SHARED /* recommended */, dev->v4l2_fd, dev->mem[i].buf.m.offset);
if (MAP_FAILED == dev->mem[i].start) {
printf("V4L2: Unable to map buffer %u: %s (%d).\n", i, strerror(errno), errno);
dev->mem[i].length = 0;
ret = -EINVAL;
goto err_free;
}
dev->mem[i].length = dev->mem[i].buf.length;
printf("V4L2: Buffer %u mapped at address %p.\n", i, dev->mem[i].start);
}
dev->nbufs = req.count;
printf("V4L2: %u buffers allocated.\n", req.count);
return 0;
err_free:
free(dev->mem);
err:
return ret;
}
static int v4l2_reqbufs_userptr(struct v4l2_device *dev, int nbufs)
{
struct v4l2_requestbuffers req;
int ret;
CLEAR(req);
req.count = nbufs;
req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
req.memory = V4L2_MEMORY_USERPTR;
ret = ioctl(dev->v4l2_fd, VIDIOC_REQBUFS, &req);
if (ret < 0) {
if (ret == -EINVAL)
printf("V4L2: does not support user pointer i/o\n");
else
printf("V4L2: VIDIOC_REQBUFS error %s (%d).\n", strerror(errno), errno);
return ret;
}
dev->nbufs = req.count;
printf("V4L2: %u buffers allocated.\n", req.count);
return 0;
}
static int v4l2_reqbufs(struct v4l2_device *dev, int nbufs)
{
int ret = 0;
switch (dev->io) {
case IO_METHOD_MMAP:
ret = v4l2_reqbufs_mmap(dev, nbufs);
break;
case IO_METHOD_USERPTR:
ret = v4l2_reqbufs_userptr(dev, nbufs);
break;
default:
ret = -EINVAL;
break;
}
return ret;
}
static int v4l2_qbuf_mmap(struct v4l2_device *dev)
{
unsigned int i;
int ret;
for (i = 0; i < dev->nbufs; ++i) {
memset(&dev->mem[i].buf, 0, sizeof(dev->mem[i].buf));
dev->mem[i].buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
dev->mem[i].buf.memory = V4L2_MEMORY_MMAP;
dev->mem[i].buf.index = i;
ret = ioctl(dev->v4l2_fd, VIDIOC_QBUF, &(dev->mem[i].buf));
if (ret < 0) {
printf("V4L2: VIDIOC_QBUF failed : %s (%d).\n", strerror(errno), errno);
return ret;
}
dev->qbuf_count++;
}
return 0;
}
static int v4l2_qbuf(struct v4l2_device *dev)
{
int ret = 0;
switch (dev->io) {
case IO_METHOD_MMAP:
ret = v4l2_qbuf_mmap(dev);
break;
case IO_METHOD_USERPTR:
/* Empty. */
ret = 0;
break;
default:
ret = -EINVAL;
break;
}
return ret;
}
static int v4l2_process_data(struct v4l2_device *dev)
{
int ret;
struct v4l2_buffer vbuf;
struct v4l2_buffer ubuf;
/* Return immediately if V4l2 streaming has not yet started. */
if (!dev->is_streaming)
return 0;
if (dev->udev->first_buffer_queued)
if (dev->dqbuf_count >= dev->qbuf_count)
return 0;
/* Dequeue spent buffer rom V4L2 domain. */
CLEAR(vbuf);
vbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
switch (dev->io) {
case IO_METHOD_USERPTR:
vbuf.memory = V4L2_MEMORY_USERPTR;
break;
case IO_METHOD_MMAP:
default:
vbuf.memory = V4L2_MEMORY_MMAP;
break;
}
ret = ioctl(dev->v4l2_fd, VIDIOC_DQBUF, &vbuf);
if (ret < 0) {
return ret;
}
dev->dqbuf_count++;
#ifdef ENABLE_BUFFER_DEBUG
printf("Dequeueing buffer at V4L2 side = %d\n", vbuf.index);
#endif
/* Queue video buffer to UVC domain. */
CLEAR(ubuf);
ubuf.type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
switch (dev->udev->io) {
case IO_METHOD_MMAP:
ubuf.memory = V4L2_MEMORY_MMAP;
ubuf.length = vbuf.length;
ubuf.index = vbuf.index;
ubuf.bytesused = vbuf.bytesused;
break;
case IO_METHOD_USERPTR:
default:
ubuf.memory = V4L2_MEMORY_USERPTR;
ubuf.m.userptr = (unsigned long)dev->mem[vbuf.index].start;
ubuf.length = dev->mem[vbuf.index].length;
ubuf.index = vbuf.index;
ubuf.bytesused = vbuf.bytesused;
break;
}
ret = ioctl(dev->udev->uvc_fd, VIDIOC_QBUF, &ubuf);
if (ret < 0) {
/* Check for a USB disconnect/shutdown event. */
if (errno == ENODEV) {
dev->udev->uvc_shutdown_requested = 1;
printf(
"UVC: Possible USB shutdown requested from "
"Host, seen during VIDIOC_QBUF\n");
return 0;
} else {
return ret;
}
}
dev->udev->qbuf_count++;
#ifdef ENABLE_BUFFER_DEBUG
printf("Queueing buffer at UVC side = %d\n", ubuf.index);
#endif
if (!dev->udev->first_buffer_queued && !dev->udev->run_standalone) {
uvc_video_stream(dev->udev, 1);
dev->udev->first_buffer_queued = 1;
dev->udev->is_streaming = 1;
}
return 0;
}
/* ---------------------------------------------------------------------------
* V4L2 generic stuff
*/
static int v4l2_get_format(struct v4l2_device *dev)
{
struct v4l2_format fmt;
int ret;
CLEAR(fmt);
fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
ret = ioctl(dev->v4l2_fd, VIDIOC_G_FMT, &fmt);
if (ret < 0) {
return ret;
}
printf("V4L2: Getting current format: %c%c%c%c %ux%u\n", pixfmtstr(fmt.fmt.pix.pixelformat), fmt.fmt.pix.width,
fmt.fmt.pix.height);
return 0;
}
static int v4l2_set_format(struct v4l2_device *dev, struct v4l2_format *fmt)
{
int ret;
ret = ioctl(dev->v4l2_fd, VIDIOC_S_FMT, fmt);
if (ret < 0) {
printf("V4L2: Unable to set format %s (%d).\n", strerror(errno), errno);
return ret;
}
printf("V4L2: Setting format to: %c%c%c%c %ux%u\n", pixfmtstr(fmt->fmt.pix.pixelformat), fmt->fmt.pix.width,
fmt->fmt.pix.height);
return 0;
}
static int v4l2_set_ctrl(struct v4l2_device *dev, int new_val, int ctrl)
{
struct v4l2_queryctrl queryctrl;
struct v4l2_control control;
int ret;
CLEAR(queryctrl);
switch (ctrl) {
case V4L2_CID_BRIGHTNESS:
queryctrl.id = V4L2_CID_BRIGHTNESS;
ret = ioctl(dev->v4l2_fd, VIDIOC_QUERYCTRL, &queryctrl);
if (-1 == ret) {
if (errno != EINVAL)
printf(
"V4L2: VIDIOC_QUERYCTRL"
" failed: %s (%d).\n",
strerror(errno), errno);
else
printf(
"V4L2_CID_BRIGHTNESS is not"
" supported: %s (%d).\n",
strerror(errno), errno);
return ret;
} else if (queryctrl.flags & V4L2_CTRL_FLAG_DISABLED) {
printf("V4L2_CID_BRIGHTNESS is not supported.\n");
ret = -EINVAL;
return ret;
} else {
CLEAR(control);
control.id = V4L2_CID_BRIGHTNESS;
control.value = new_val;
ret = ioctl(dev->v4l2_fd, VIDIOC_S_CTRL, &control);
if (-1 == ret) {
printf("V4L2: VIDIOC_S_CTRL failed: %s (%d).\n", strerror(errno), errno);
return ret;
}
}
printf("V4L2: Brightness control changed to value = 0x%x\n", new_val);
break;
default:
/* TODO: We don't support any other controls. */
return -EINVAL;
}
return 0;
}
static int v4l2_start_capturing(struct v4l2_device *dev)
{
int type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
int ret;
ret = ioctl(dev->v4l2_fd, VIDIOC_STREAMON, &type);
if (ret < 0) {
printf("V4L2: Unable to start streaming: %s (%d).\n", strerror(errno), errno);
return ret;
}
printf("V4L2: Starting video stream.\n");
return 0;
}
static int v4l2_stop_capturing(struct v4l2_device *dev)
{
enum v4l2_buf_type type;
int ret;
switch (dev->io) {
case IO_METHOD_MMAP:
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
ret = ioctl(dev->v4l2_fd, VIDIOC_STREAMOFF, &type);
if (ret < 0) {
printf("V4L2: VIDIOC_STREAMOFF failed: %s (%d).\n", strerror(errno), errno);
return ret;
}
break;
default:
/* Nothing to do. */
break;
}
return 0;
}
static int v4l2_open(struct v4l2_device **v4l2, char *devname, struct v4l2_format *s_fmt)
{
struct v4l2_device *dev;
struct v4l2_capability cap;
int fd;
int ret = -EINVAL;
fd = open(devname, O_RDWR | O_NONBLOCK, 0);
if (fd == -1) {
printf("V4L2: device open failed: %s (%d).\n", strerror(errno), errno);
return ret;
}
ret = ioctl(fd, VIDIOC_QUERYCAP, &cap);
if (ret < 0) {
printf("V4L2: VIDIOC_QUERYCAP failed: %s (%d).\n", strerror(errno), errno);
goto err;
}
if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
printf("V4L2: %s is no video capture device\n", devname);
goto err;
}
if (!(cap.capabilities & V4L2_CAP_STREAMING)) {
printf("V4L2: %s does not support streaming i/o\n", devname);
goto err;
}
dev = calloc(1, sizeof *dev);
if (dev == NULL) {
ret = -ENOMEM;
goto err;
}
printf("V4L2 device is %s on bus %s\n", cap.card, cap.bus_info);
dev->v4l2_fd = fd;
/* Get the default image format supported. */
ret = v4l2_get_format(dev);
if (ret < 0)
goto err_free;
/*
* Set the desired image format.
* Note: VIDIOC_S_FMT may change width and height.
*/
ret = v4l2_set_format(dev, s_fmt);
if (ret < 0)
goto err_free;
/* Get the changed image format. */
ret = v4l2_get_format(dev);
if (ret < 0)
goto err_free;
printf("v4l2 open succeeded, file descriptor = %d\n", fd);
*v4l2 = dev;
return 0;
err_free:
free(dev);
err:
close(fd);
return ret;
}
static void v4l2_close(struct v4l2_device *dev)
{
close(dev->v4l2_fd);
free(dev);
}
/* ---------------------------------------------------------------------------
* UVC generic stuff
*/
static int uvc_video_set_format(struct uvc_device *dev)
{
struct v4l2_format fmt;
int ret;
CLEAR(fmt);
fmt.type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
fmt.fmt.pix.width = dev->width;
fmt.fmt.pix.height = dev->height;
fmt.fmt.pix.pixelformat = dev->fcc;
fmt.fmt.pix.field = V4L2_FIELD_NONE;
if (dev->fcc == V4L2_PIX_FMT_MJPEG)
fmt.fmt.pix.sizeimage = dev->imgsize * 1.5;
ret = ioctl(dev->uvc_fd, VIDIOC_S_FMT, &fmt);
if (ret < 0) {
printf("UVC: Unable to set format %s (%d).\n", strerror(errno), errno);
return ret;
}
printf("UVC: Setting format to: %c%c%c%c %ux%u\n", pixfmtstr(dev->fcc), dev->width, dev->height);
return 0;
}
static int uvc_video_stream(struct uvc_device *dev, int enable)
{
int type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
int ret;
if (!enable) {
ret = ioctl(dev->uvc_fd, VIDIOC_STREAMOFF, &type);
if (ret < 0) {
printf("UVC: VIDIOC_STREAMOFF failed: %s (%d).\n", strerror(errno), errno);
return ret;
}
printf("UVC: Stopping video stream.\n");
return 0;
}
ret = ioctl(dev->uvc_fd, VIDIOC_STREAMON, &type);
if (ret < 0) {
printf("UVC: Unable to start streaming %s (%d).\n", strerror(errno), errno);
return ret;
}
printf("UVC: Starting video stream.\n");
dev->uvc_shutdown_requested = 0;
return 0;
}
static int uvc_uninit_device(struct uvc_device *dev)
{
unsigned int i;
int ret;
switch (dev->io) {
case IO_METHOD_MMAP:
for (i = 0; i < dev->nbufs; ++i) {
ret = munmap(dev->mem[i].start, dev->mem[i].length);
if (ret < 0) {
printf("UVC: munmap failed\n");
return ret;
}
}
free(dev->mem);
break;
case IO_METHOD_USERPTR:
default:
if (dev->run_standalone) {
for (i = 0; i < dev->nbufs; ++i)
free(dev->dummy_buf[i].start);
free(dev->dummy_buf);
}
break;
}
return 0;
}
static int uvc_open(struct uvc_device **uvc, char *devname)
{
struct uvc_device *dev;
struct v4l2_capability cap;
int fd;
int ret = -EINVAL;
fd = open(devname, O_RDWR | O_NONBLOCK);
if (fd == -1) {
printf("UVC: device open failed: %s (%d).\n", strerror(errno), errno);
return ret;
}
ret = ioctl(fd, VIDIOC_QUERYCAP, &cap);
if (ret < 0) {
printf("UVC: unable to query uvc device: %s (%d)\n", strerror(errno), errno);
goto err;
}
if (!(cap.capabilities & V4L2_CAP_VIDEO_OUTPUT)) {
printf("UVC: %s is no video output device\n", devname);
goto err;
}
dev = calloc(1, sizeof *dev);
if (dev == NULL) {
ret = -ENOMEM;
goto err;
}
printf("uvc device is %s on bus %s\n", cap.card, cap.bus_info);
printf("uvc open succeeded, file descriptor = %d\n", fd);
dev->uvc_fd = fd;
*uvc = dev;
return 0;
err:
close(fd);
return ret;
}
static void uvc_close(struct uvc_device *dev)
{
close(dev->uvc_fd);
free(dev->imgdata);
free(dev);
}
/* ---------------------------------------------------------------------------
* UVC streaming related
*/
static void uvc_video_fill_buffer(struct uvc_device *dev, struct v4l2_buffer *buf)
{
unsigned int bpl;
unsigned int i;
switch (dev->fcc) {
case V4L2_PIX_FMT_YUYV:
/* Fill the buffer with video data. */
bpl = dev->width * 2;
for (i = 0; i < dev->height; ++i)
memset(dev->mem[buf->index].start + i * bpl, dev->color++, bpl);
buf->bytesused = bpl * dev->height;
break;
case V4L2_PIX_FMT_MJPEG:
memcpy(dev->mem[buf->index].start, dev->imgdata, dev->imgsize);
buf->bytesused = dev->imgsize;
break;
}
}
static int uvc_video_process(struct uvc_device *dev)
{
struct v4l2_buffer ubuf;
struct v4l2_buffer vbuf;
unsigned int i;
int ret;
/*
* Return immediately if UVC video output device has not started
* streaming yet.
*/
if (!dev->is_streaming)
return 0;
/* Prepare a v4l2 buffer to be dequeued from UVC domain. */
CLEAR(ubuf);
ubuf.type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
switch (dev->io) {
case IO_METHOD_MMAP:
ubuf.memory = V4L2_MEMORY_MMAP;
break;
case IO_METHOD_USERPTR:
default:
ubuf.memory = V4L2_MEMORY_USERPTR;
break;
}
if (dev->run_standalone) {
/* UVC stanalone setup. */
ret = ioctl(dev->uvc_fd, VIDIOC_DQBUF, &ubuf);
if (ret < 0)
return ret;
dev->dqbuf_count++;
#ifdef ENABLE_BUFFER_DEBUG
printf("DeQueued buffer at UVC side = %d\n", ubuf.index);
#endif
uvc_video_fill_buffer(dev, &ubuf);
ret = ioctl(dev->uvc_fd, VIDIOC_QBUF, &ubuf);
if (ret < 0)
return ret;
dev->qbuf_count++;
#ifdef ENABLE_BUFFER_DEBUG
printf("ReQueueing buffer at UVC side = %d\n", ubuf.index);
#endif
} else {
/* UVC - V4L2 integrated path. */
/*
* Return immediately if V4L2 video capture device has not
* started streaming yet or if QBUF was not called even once on
* the UVC side.
*/
if (!dev->vdev->is_streaming || !dev->first_buffer_queued)
return 0;
/*
* Do not dequeue buffers from UVC side until there are atleast
* 2 buffers available at UVC domain.
*/
if (!dev->uvc_shutdown_requested)
if ((dev->dqbuf_count + 1) >= dev->qbuf_count)
return 0;
/* Dequeue the spent buffer from UVC domain */
ret = ioctl(dev->uvc_fd, VIDIOC_DQBUF, &ubuf);
if (ret < 0) {
printf("UVC: Unable to dequeue buffer: %s (%d).\n", strerror(errno), errno);
return ret;
}
if (dev->io == IO_METHOD_USERPTR)
for (i = 0; i < dev->nbufs; ++i)
if (ubuf.m.userptr == (unsigned long)dev->vdev->mem[i].start && ubuf.length == dev->vdev->mem[i].length)
break;
dev->dqbuf_count++;
#ifdef ENABLE_BUFFER_DEBUG
printf("DeQueued buffer at UVC side=%d\n", ubuf.index);
#endif
/*
* If the dequeued buffer was marked with state ERROR by the
* underlying UVC driver gadget, do not queue the same to V4l2
* and wait for a STREAMOFF event on UVC side corresponding to
* set_alt(0). So, now all buffers pending at UVC end will be
* dequeued one-by-one and we will enter a state where we once
* again wait for a set_alt(1) command from the USB host side.
*/
if (ubuf.flags & V4L2_BUF_FLAG_ERROR) {
dev->uvc_shutdown_requested = 1;
printf(