On 6/22/19 12:50 AM, Ezequiel Garcia wrote:
> Currently, the v4l2 control code is a bit silent on errors.
> Add debug messages on (hopefully) most of the error paths.
>
> Signed-off-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>
> ---
> Changes from v1:
> * Drop changes in the debug parameter semantics.
> * Drop new module debug parameter.
> * Add documentation.
> * Add a debug error in all places where control can fail.
> * Reorder the vdev parameter, to make the patch less invasive.
> ---
> Documentation/media/kapi/v4l2-dev.rst | 1 +
> drivers/media/platform/omap3isp/ispvideo.c | 2 +-
> drivers/media/v4l2-core/v4l2-ctrls.c | 106 ++++++++++++++++-----
> drivers/media/v4l2-core/v4l2-ioctl.c | 12 +--
> drivers/media/v4l2-core/v4l2-subdev.c | 6 +-
> include/media/v4l2-ctrls.h | 9 +-
> include/media/v4l2-ioctl.h | 2 +
> 7 files changed, 100 insertions(+), 38 deletions(-)
>
> diff --git a/Documentation/media/kapi/v4l2-dev.rst b/Documentation/media/kapi/v4l2-dev.rst
> index b359f1804bbe..4c5a15c53dbf 100644
> --- a/Documentation/media/kapi/v4l2-dev.rst
> +++ b/Documentation/media/kapi/v4l2-dev.rst
> @@ -288,6 +288,7 @@ Mask Description
> 0x08 Log the read and write file operations and the VIDIOC_QBUF and
> VIDIOC_DQBUF ioctls.
> 0x10 Log the poll file operation.
> +0x20 Log error and messages in the control operations.
> ===== ================================================================
>
> Video device cleanup
> diff --git a/drivers/media/platform/omap3isp/ispvideo.c b/drivers/media/platform/omap3isp/ispvideo.c
> index 175bbed9a235..abc945cc05c9 100644
> --- a/drivers/media/platform/omap3isp/ispvideo.c
> +++ b/drivers/media/platform/omap3isp/ispvideo.c
> @@ -1028,7 +1028,7 @@ static int isp_video_check_external_subdevs(struct isp_video *video,
> ctrls.count = 1;
> ctrls.controls = &ctrl;
>
> - ret = v4l2_g_ext_ctrls(pipe->external->ctrl_handler, NULL, &ctrls);
> + ret = v4l2_g_ext_ctrls(pipe->external->ctrl_handler, &video->video, NULL, &ctrls);
> if (ret < 0) {
> dev_warn(isp->dev, "no pixel rate control in subdev %s\n",
> pipe->external->name);
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> index 2d7525e2d9eb..4ee703e04ef2 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -6,6 +6,8 @@
>
> */
>
> +#define pr_fmt(fmt) "v4l2-ctrls: " fmt
> +
> #include <linux/ctype.h>
> #include <linux/mm.h>
> #include <linux/slab.h>
> @@ -16,6 +18,12 @@
> #include <media/v4l2-event.h>
> #include <media/v4l2-dev.h>
>
> +#define dprintk(vdev, fmt, arg...) do { \
> + if (vdev->dev_debug & V4L2_DEV_DEBUG_CTRL) \
This isn't very robust if vdev is NULL. I know it shouldn't, but it's
better to check for this.
I'd use this instead:
if (!WARN_ON(!vdev) && ((vdev)->dev_debug & V4L2_DEV_DEBUG_CTRL)) \
That way nothing crashes if vdev is NULL, and you get a warning as well in that case.
Regards,
Hans
> + printk(KERN_DEBUG pr_fmt("%s: %s: " fmt), \
> + __func__, video_device_node_name(vdev), ##arg); \
> +} while (0)
> +
> #define has_op(master, op) \
> (master->ops && master->ops->op)
> #define call_op(master, op) \
> @@ -3211,6 +3219,7 @@ static int v4l2_ctrl_request_bind(struct media_request *req,
> static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
> struct v4l2_ext_controls *cs,
> struct v4l2_ctrl_helper *helpers,
> + struct video_device *vdev,
> bool get)
> {
> struct v4l2_ctrl_helper *h;
> @@ -3228,20 +3237,28 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
> if (cs->which &&
> cs->which != V4L2_CTRL_WHICH_DEF_VAL &&
> cs->which != V4L2_CTRL_WHICH_REQUEST_VAL &&
> - V4L2_CTRL_ID2WHICH(id) != cs->which)
> + V4L2_CTRL_ID2WHICH(id) != cs->which) {
> + dprintk(vdev, "invalid which 0x%x or control id 0x%x\n", cs->which, id);
> return -EINVAL;
> + }
>
> /* Old-style private controls are not allowed for
> extended controls */
> - if (id >= V4L2_CID_PRIVATE_BASE)
> + if (id >= V4L2_CID_PRIVATE_BASE) {
> + dprintk(vdev, "old-style private controls not allowed for extended controls\n");
> return -EINVAL;
> + }
> ref = find_ref_lock(hdl, id);
> - if (ref == NULL)
> + if (ref == NULL) {
> + dprintk(vdev, "cannot find control id 0x%x\n", id);
> return -EINVAL;
> + }
> h->ref = ref;
> ctrl = ref->ctrl;
> - if (ctrl->flags & V4L2_CTRL_FLAG_DISABLED)
> + if (ctrl->flags & V4L2_CTRL_FLAG_DISABLED) {
> + dprintk(vdev, "control id 0x%x is disabled\n", id);
> return -EINVAL;
> + }
>
> if (ctrl->cluster[0]->ncontrols > 1)
> have_clusters = true;
> @@ -3251,10 +3268,16 @@ static int prepare_ext_ctrls(struct v4l2_ctrl_handler *hdl,
> unsigned tot_size = ctrl->elems * ctrl->elem_size;
>
> if (c->size < tot_size) {
> + /*
> + * In the get case the application first queries
> + * to obtain the size of the control.
> + */
> if (get) {
> c->size = tot_size;
> return -ENOSPC;
> }
> + dprintk(vdev, "pointer control id 0x%x size too small, %d bytes but %d bytes needed\n",
> + id, c->size, tot_size);
> return -EFAULT;
> }
> c->size = tot_size;
> @@ -3315,7 +3338,8 @@ static int class_check(struct v4l2_ctrl_handler *hdl, u32 which)
>
> /* Get extended controls. Allocates the helpers array if needed. */
> static int v4l2_g_ext_ctrls_common(struct v4l2_ctrl_handler *hdl,
> - struct v4l2_ext_controls *cs)
> + struct v4l2_ext_controls *cs,
> + struct video_device *vdev)
> {
> struct v4l2_ctrl_helper helper[4];
> struct v4l2_ctrl_helper *helpers = helper;
> @@ -3341,7 +3365,7 @@ static int v4l2_g_ext_ctrls_common(struct v4l2_ctrl_handler *hdl,
> return -ENOMEM;
> }
>
> - ret = prepare_ext_ctrls(hdl, cs, helpers, true);
> + ret = prepare_ext_ctrls(hdl, cs, helpers, vdev, true);
> cs->error_idx = cs->count;
>
> for (i = 0; !ret && i < cs->count; i++)
> @@ -3434,8 +3458,8 @@ v4l2_ctrls_find_req_obj(struct v4l2_ctrl_handler *hdl,
> return obj;
> }
>
> -int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct media_device *mdev,
> - struct v4l2_ext_controls *cs)
> +int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct video_device *vdev,
> + struct media_device *mdev, struct v4l2_ext_controls *cs)
> {
> struct media_request_object *obj = NULL;
> struct media_request *req = NULL;
> @@ -3471,7 +3495,7 @@ int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct media_device *mdev,
> req_obj);
> }
>
> - ret = v4l2_g_ext_ctrls_common(hdl, cs);
> + ret = v4l2_g_ext_ctrls_common(hdl, cs, vdev);
>
> if (obj) {
> media_request_unlock_for_access(req);
> @@ -3614,7 +3638,9 @@ static int try_or_set_cluster(struct v4l2_fh *fh, struct v4l2_ctrl *master,
>
> /* Validate controls. */
> static int validate_ctrls(struct v4l2_ext_controls *cs,
> - struct v4l2_ctrl_helper *helpers, bool set)
> + struct v4l2_ctrl_helper *helpers,
> + struct video_device *vdev,
> + bool set)
> {
> unsigned i;
> int ret = 0;
> @@ -3626,16 +3652,20 @@ static int validate_ctrls(struct v4l2_ext_controls *cs,
>
> cs->error_idx = i;
>
> - if (ctrl->flags & V4L2_CTRL_FLAG_READ_ONLY)
> + if (ctrl->flags & V4L2_CTRL_FLAG_READ_ONLY) {
> + dprintk(vdev, "control id 0x%x is read-only\n", ctrl->id);
> return -EACCES;
> + }
> /* This test is also done in try_set_control_cluster() which
> is called in atomic context, so that has the final say,
> but it makes sense to do an up-front check as well. Once
> an error occurs in try_set_control_cluster() some other
> controls may have been set already and we want to do a
> best-effort to avoid that. */
> - if (set && (ctrl->flags & V4L2_CTRL_FLAG_GRABBED))
> + if (set && (ctrl->flags & V4L2_CTRL_FLAG_GRABBED)) {
> + dprintk(vdev, "control id 0x%x is grabbed, cannot set\n", ctrl->id);
> return -EBUSY;
> + }
> /*
> * Skip validation for now if the payload needs to be copied
> * from userspace into kernelspace. We'll validate those later.
> @@ -3670,7 +3700,8 @@ static void update_from_auto_cluster(struct v4l2_ctrl *master)
> /* Try or try-and-set controls */
> static int try_set_ext_ctrls_common(struct v4l2_fh *fh,
> struct v4l2_ctrl_handler *hdl,
> - struct v4l2_ext_controls *cs, bool set)
> + struct v4l2_ext_controls *cs,
> + struct video_device *vdev, bool set)
> {
> struct v4l2_ctrl_helper helper[4];
> struct v4l2_ctrl_helper *helpers = helper;
> @@ -3680,13 +3711,17 @@ static int try_set_ext_ctrls_common(struct v4l2_fh *fh,
> cs->error_idx = cs->count;
>
> /* Default value cannot be changed */
> - if (cs->which == V4L2_CTRL_WHICH_DEF_VAL)
> + if (cs->which == V4L2_CTRL_WHICH_DEF_VAL) {
> + dprintk(vdev, "%s: cannot change default value\n", video_device_node_name(vdev));
> return -EINVAL;
> + }
>
> cs->which = V4L2_CTRL_ID2WHICH(cs->which);
>
> - if (hdl == NULL)
> + if (hdl == NULL) {
> + dprintk(vdev, "%s: invalid null control handler\n", video_device_node_name(vdev));
> return -EINVAL;
> + }
>
> if (cs->count == 0)
> return class_check(hdl, cs->which);
> @@ -3697,9 +3732,9 @@ static int try_set_ext_ctrls_common(struct v4l2_fh *fh,
> if (!helpers)
> return -ENOMEM;
> }
> - ret = prepare_ext_ctrls(hdl, cs, helpers, false);
> + ret = prepare_ext_ctrls(hdl, cs, helpers, vdev, false);
> if (!ret)
> - ret = validate_ctrls(cs, helpers, set);
> + ret = validate_ctrls(cs, helpers, vdev, set);
> if (ret && set)
> cs->error_idx = cs->count;
> for (i = 0; !ret && i < cs->count; i++) {
> @@ -3784,7 +3819,8 @@ static int try_set_ext_ctrls_common(struct v4l2_fh *fh,
> }
>
> static int try_set_ext_ctrls(struct v4l2_fh *fh,
> - struct v4l2_ctrl_handler *hdl, struct media_device *mdev,
> + struct v4l2_ctrl_handler *hdl,
> + struct video_device *vdev, struct media_device *mdev,
> struct v4l2_ext_controls *cs, bool set)
> {
> struct media_request_object *obj = NULL;
> @@ -3792,21 +3828,32 @@ static int try_set_ext_ctrls(struct v4l2_fh *fh,
> int ret;
>
> if (cs->which == V4L2_CTRL_WHICH_REQUEST_VAL) {
> - if (!mdev || cs->request_fd < 0)
> + if (!mdev) {
> + dprintk(vdev, "%s: missing media device\n", video_device_node_name(vdev));
> + return -EINVAL;
> + }
> +
> + if (cs->request_fd < 0) {
> + dprintk(vdev, "%s: invalid request fd %d\n", video_device_node_name(vdev), cs->request_fd);
> return -EINVAL;
> + }
>
> req = media_request_get_by_fd(mdev, cs->request_fd);
> - if (IS_ERR(req))
> + if (IS_ERR(req)) {
> + dprintk(vdev, "%s: cannot find request fd %d\n", video_device_node_name(vdev), cs->request_fd);
> return PTR_ERR(req);
> + }
>
> ret = media_request_lock_for_update(req);
> if (ret) {
> + dprintk(vdev, "%s: cannot lock request fd %d\n", video_device_node_name(vdev), cs->request_fd);
> media_request_put(req);
> return ret;
> }
>
> obj = v4l2_ctrls_find_req_obj(hdl, req, set);
> if (IS_ERR(obj)) {
> + dprintk(vdev, "%s: cannot find request object for request fd %d\n", video_device_node_name(vdev), cs->request_fd);
> media_request_unlock_for_update(req);
> media_request_put(req);
> return PTR_ERR(obj);
> @@ -3815,7 +3862,9 @@ static int try_set_ext_ctrls(struct v4l2_fh *fh,
> req_obj);
> }
>
> - ret = try_set_ext_ctrls_common(fh, hdl, cs, set);
> + ret = try_set_ext_ctrls_common(fh, hdl, cs, vdev, set);
> + if (ret)
> + dprintk(vdev, "%s: try_set_ext_ctrls_common failed (%d)\n", video_device_node_name(vdev), ret);
>
> if (obj) {
> media_request_unlock_for_update(req);
> @@ -3826,17 +3875,22 @@ static int try_set_ext_ctrls(struct v4l2_fh *fh,
> return ret;
> }
>
> -int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct media_device *mdev,
> +int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl,
> + struct video_device *vdev,
> + struct media_device *mdev,
> struct v4l2_ext_controls *cs)
> {
> - return try_set_ext_ctrls(NULL, hdl, mdev, cs, false);
> + return try_set_ext_ctrls(NULL, hdl, vdev, mdev, cs, false);
> }
> EXPORT_SYMBOL(v4l2_try_ext_ctrls);
>
> -int v4l2_s_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
> - struct media_device *mdev, struct v4l2_ext_controls *cs)
> +int v4l2_s_ext_ctrls(struct v4l2_fh *fh,
> + struct v4l2_ctrl_handler *hdl,
> + struct video_device *vdev,
> + struct media_device *mdev,
> + struct v4l2_ext_controls *cs)
> {
> - return try_set_ext_ctrls(fh, hdl, mdev, cs, true);
> + return try_set_ext_ctrls(fh, hdl, vdev, mdev, cs, true);
> }
> EXPORT_SYMBOL(v4l2_s_ext_ctrls);
>
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index b1f4b991dba6..e95efea1a9ca 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -2165,9 +2165,9 @@ static int v4l_g_ext_ctrls(const struct v4l2_ioctl_ops *ops,
>
> p->error_idx = p->count;
> if (vfh && vfh->ctrl_handler)
> - return v4l2_g_ext_ctrls(vfh->ctrl_handler, vfd->v4l2_dev->mdev, p);
> + return v4l2_g_ext_ctrls(vfh->ctrl_handler, vfd, vfd->v4l2_dev->mdev, p);
> if (vfd->ctrl_handler)
> - return v4l2_g_ext_ctrls(vfd->ctrl_handler, vfd->v4l2_dev->mdev, p);
> + return v4l2_g_ext_ctrls(vfd->ctrl_handler, vfd, vfd->v4l2_dev->mdev, p);
> if (ops->vidioc_g_ext_ctrls == NULL)
> return -ENOTTY;
> return check_ext_ctrls(p, 0) ? ops->vidioc_g_ext_ctrls(file, fh, p) :
> @@ -2184,9 +2184,9 @@ static int v4l_s_ext_ctrls(const struct v4l2_ioctl_ops *ops,
>
> p->error_idx = p->count;
> if (vfh && vfh->ctrl_handler)
> - return v4l2_s_ext_ctrls(vfh, vfh->ctrl_handler, vfd->v4l2_dev->mdev, p);
> + return v4l2_s_ext_ctrls(vfh, vfh->ctrl_handler, vfd, vfd->v4l2_dev->mdev, p);
> if (vfd->ctrl_handler)
> - return v4l2_s_ext_ctrls(NULL, vfd->ctrl_handler, vfd->v4l2_dev->mdev, p);
> + return v4l2_s_ext_ctrls(NULL, vfd->ctrl_handler, vfd, vfd->v4l2_dev->mdev, p);
> if (ops->vidioc_s_ext_ctrls == NULL)
> return -ENOTTY;
> return check_ext_ctrls(p, 0) ? ops->vidioc_s_ext_ctrls(file, fh, p) :
> @@ -2203,9 +2203,9 @@ static int v4l_try_ext_ctrls(const struct v4l2_ioctl_ops *ops,
>
> p->error_idx = p->count;
> if (vfh && vfh->ctrl_handler)
> - return v4l2_try_ext_ctrls(vfh->ctrl_handler, vfd->v4l2_dev->mdev, p);
> + return v4l2_try_ext_ctrls(vfh->ctrl_handler, vfd, vfd->v4l2_dev->mdev, p);
> if (vfd->ctrl_handler)
> - return v4l2_try_ext_ctrls(vfd->ctrl_handler, vfd->v4l2_dev->mdev, p);
> + return v4l2_try_ext_ctrls(vfd->ctrl_handler, vfd, vfd->v4l2_dev->mdev, p);
> if (ops->vidioc_try_ext_ctrls == NULL)
> return -ENOTTY;
> return check_ext_ctrls(p, 0) ? ops->vidioc_try_ext_ctrls(file, fh, p) :
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index f24978b80440..1b5edd3b1e6c 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -211,19 +211,19 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
> if (!vfh->ctrl_handler)
> return -ENOTTY;
> return v4l2_g_ext_ctrls(vfh->ctrl_handler,
> - sd->v4l2_dev->mdev, arg);
> + vdev, sd->v4l2_dev->mdev, arg);
>
> case VIDIOC_S_EXT_CTRLS:
> if (!vfh->ctrl_handler)
> return -ENOTTY;
> return v4l2_s_ext_ctrls(vfh, vfh->ctrl_handler,
> - sd->v4l2_dev->mdev, arg);
> + vdev, sd->v4l2_dev->mdev, arg);
>
> case VIDIOC_TRY_EXT_CTRLS:
> if (!vfh->ctrl_handler)
> return -ENOTTY;
> return v4l2_try_ext_ctrls(vfh->ctrl_handler,
> - sd->v4l2_dev->mdev, arg);
> + vdev, sd->v4l2_dev->mdev, arg);
>
> case VIDIOC_DQEVENT:
> if (!(sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS))
> diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
> index b4433483af23..c08d6cc56743 100644
> --- a/include/media/v4l2-ctrls.h
> +++ b/include/media/v4l2-ctrls.h
> @@ -1265,25 +1265,28 @@ int v4l2_s_ctrl(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
> * :ref:`VIDIOC_G_EXT_CTRLS <vidioc_g_ext_ctrls>` ioctl
> *
> * @hdl: pointer to &struct v4l2_ctrl_handler
> + * @vdev: pointer to &struct video_device
> * @mdev: pointer to &struct media_device
> * @c: pointer to &struct v4l2_ext_controls
> *
> * If hdl == NULL then they will all return -EINVAL.
> */
> -int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct media_device *mdev,
> - struct v4l2_ext_controls *c);
> +int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct video_device *vdev,
> + struct media_device *mdev, struct v4l2_ext_controls *c);
>
> /**
> * v4l2_try_ext_ctrls - Helper function to implement
> * :ref:`VIDIOC_TRY_EXT_CTRLS <vidioc_g_ext_ctrls>` ioctl
> *
> * @hdl: pointer to &struct v4l2_ctrl_handler
> + * @vdev: pointer to &struct video_device
> * @mdev: pointer to &struct media_device
> * @c: pointer to &struct v4l2_ext_controls
> *
> * If hdl == NULL then they will all return -EINVAL.
> */
> int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl,
> + struct video_device *vdev,
> struct media_device *mdev,
> struct v4l2_ext_controls *c);
>
> @@ -1293,12 +1296,14 @@ int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl,
> *
> * @fh: pointer to &struct v4l2_fh
> * @hdl: pointer to &struct v4l2_ctrl_handler
> + * @vdev: pointer to &struct video_device
> * @mdev: pointer to &struct media_device
> * @c: pointer to &struct v4l2_ext_controls
> *
> * If hdl == NULL then they will all return -EINVAL.
> */
> int v4l2_s_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
> + struct video_device *vdev,
> struct media_device *mdev,
> struct v4l2_ext_controls *c);
>
> diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
> index 400f2e46c108..4bba65a59d46 100644
> --- a/include/media/v4l2-ioctl.h
> +++ b/include/media/v4l2-ioctl.h
> @@ -602,6 +602,8 @@ struct v4l2_ioctl_ops {
> #define V4L2_DEV_DEBUG_STREAMING 0x08
> /* Log poll() */
> #define V4L2_DEV_DEBUG_POLL 0x10
> +/* Log controls */
> +#define V4L2_DEV_DEBUG_CTRL 0x20
>
> /* Video standard functions */
>
>
