On 2/27/19 6:07 PM, Ezequiel Garcia wrote:
> Currently, the v4l2 control code is a bit silent on errors.
> Now that we have a debug parameter, it's possible to enable
> debugging messages here.
>
> Add debug messages on (hopefully) most of the error paths.
> Since it's really hard to associate all these errors
> to video device instance, we are forced to use the global
> debug parameter only.
>
> Add a warning in case the user enables control debugging
> at the per-device dev_debug level.
>
> Signed-off-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>
> ---
> drivers/media/v4l2-core/v4l2-ctrls.c | 93 +++++++++++++++++++++------
> drivers/media/v4l2-core/v4l2-dev.c | 2 +
> drivers/media/v4l2-core/v4l2-ioctl.c | 8 +--
> drivers/media/v4l2-core/v4l2-subdev.c | 4 +-
> include/media/v4l2-ctrls.h | 9 ++-
> include/media/v4l2-ioctl.h | 2 +
> 6 files changed, 91 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> index b79d3bbd8350..af8ad83d1e08 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -18,6 +18,8 @@
> Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> */
>
> +#define pr_fmt(fmt) "v4l2-ctrls: " fmt
> +
> #include <linux/ctype.h>
> #include <linux/mm.h>
> #include <linux/slab.h>
> @@ -28,6 +30,14 @@
> #include <media/v4l2-event.h>
> #include <media/v4l2-dev.h>
>
> +extern unsigned int videodev_debug;
> +
> +#define dprintk(fmt, arg...) do { \
> + if (videodev_debug & V4L2_DEV_DEBUG_CTRL) \
> + printk(KERN_DEBUG pr_fmt("%s: " fmt), \
> + __func__, ##arg); \
> +} while (0)
> +
> #define has_op(master, op) \
> (master->ops && master->ops->op)
> #define call_op(master, op) \
> @@ -1952,8 +1962,11 @@ static int validate_new(const struct v4l2_ctrl *ctrl, union v4l2_ctrl_ptr p_new)
> unsigned idx;
> int err = 0;
>
> - for (idx = 0; !err && idx < ctrl->elems; idx++)
> + for (idx = 0; !err && idx < ctrl->elems; idx++) {
> err = ctrl->type_ops->validate(ctrl, idx, p_new);
> + if (err)
> + dprintk("failed to validate control id 0x%x (%d)\n", ctrl->id, err);
> + }
> return err;
> }
>
> @@ -3136,20 +3149,28 @@ 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("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("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("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("control id 0x%x is disabled\n", id);
> return -EINVAL;
> + }
>
> if (ctrl->cluster[0]->ncontrols > 1)
> have_clusters = true;
> @@ -3159,10 +3180,16 @@ 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("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;
> @@ -3534,16 +3561,20 @@ 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("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("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.
> @@ -3576,7 +3607,8 @@ 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,
> +static int try_set_ext_ctrls_common(struct video_device *vdev,
> + struct v4l2_fh *fh,
> struct v4l2_ctrl_handler *hdl,
> struct v4l2_ext_controls *cs, bool set)
> {
> @@ -3588,13 +3620,17 @@ 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("%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("%s: invalid null control handler\n", video_device_node_name(vdev));
> return -EINVAL;
> + }
>
> if (cs->count == 0)
> return class_check(hdl, cs->which);
> @@ -3691,7 +3727,8 @@ static int try_set_ext_ctrls_common(struct v4l2_fh *fh,
> return ret;
> }
>
> -static int try_set_ext_ctrls(struct v4l2_fh *fh,
> +static int try_set_ext_ctrls(struct video_device *vdev,
> + struct v4l2_fh *fh,
> struct v4l2_ctrl_handler *hdl, struct media_device *mdev,
> struct v4l2_ext_controls *cs, bool set)
> {
> @@ -3700,21 +3737,32 @@ 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("%s: missing media device\n", video_device_node_name(vdev));
> + return -EINVAL;
> + }
> +
> + if (cs->request_fd < 0) {
> + dprintk("%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("%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("%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("%s: cannot find request object for request fd %d\n", video_device_node_name(vdev), cs->request_fd);
These lines are way too long. Just add a newline after the first comma.
Same elsewhere.
> media_request_unlock_for_update(req);
> media_request_put(req);
> return PTR_ERR(obj);
> @@ -3723,7 +3771,9 @@ 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(vdev, fh, hdl, cs, set);
> + if (ret)
> + dprintk("%s: try_set_ext_ctrls_common failed (%d)\n", video_device_node_name(vdev), ret);
>
> if (obj) {
> media_request_unlock_for_update(req);
> @@ -3734,17 +3784,22 @@ 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 video_device *vdev,
> + struct v4l2_ctrl_handler *hdl,
> + struct media_device *mdev,
> struct v4l2_ext_controls *cs)
> {
> - return try_set_ext_ctrls(NULL, hdl, mdev, cs, false);
> + return try_set_ext_ctrls(vdev, NULL, hdl, 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 video_device *vdev,
> + struct v4l2_fh *fh,
> + struct v4l2_ctrl_handler *hdl,
> + struct media_device *mdev,
> + struct v4l2_ext_controls *cs)
> {
> - return try_set_ext_ctrls(fh, hdl, mdev, cs, true);
> + return try_set_ext_ctrls(vdev, fh, hdl, mdev, cs, true);
> }
> EXPORT_SYMBOL(v4l2_s_ext_ctrls);
>
> diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
> index 39d22bfbe420..c6bcc9ea1122 100644
> --- a/drivers/media/v4l2-core/v4l2-dev.c
> +++ b/drivers/media/v4l2-core/v4l2-dev.c
> @@ -83,6 +83,8 @@ static ssize_t dev_debug_store(struct device *cd, struct device_attribute *attr,
> if (res)
> return res;
>
> + if (value & V4L2_DEV_DEBUG_CTRL)
> + pr_warn_once("Warning: V4L2_DEV_DEBUG_CTRL cannot be enabled via the dev_debug attribute.\n");
Actually, you can for those functions that have the vdev pointer.
And I think you can pass vdev on to more functions. Certainly validate_ctrls()
and possibly all of them.
> vdev->dev_debug = value;
> return len;
> }
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 6f707466b5d2..078f75eb0a19 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -2180,9 +2180,9 @@ 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(vfd, vfh, vfh->ctrl_handler, 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(vfd, vfh, vfd->ctrl_handler, vfd->v4l2_dev->mdev, p);
Copy-and-paste error: vfh should be NULL.
> if (ops->vidioc_s_ext_ctrls == NULL)
> return -ENOTTY;
> return check_ext_ctrls(p, 0) ? ops->vidioc_s_ext_ctrls(file, fh, p) :
> @@ -2199,9 +2199,9 @@ 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(vfd, vfh->ctrl_handler, 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, vfd->ctrl_handler, 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 f5f0d71ec745..3a09d4441ca3 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -228,13 +228,13 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
> case VIDIOC_S_EXT_CTRLS:
> if (!vfh->ctrl_handler)
> return -ENOTTY;
> - return v4l2_s_ext_ctrls(vfh, vfh->ctrl_handler,
> + return v4l2_s_ext_ctrls(vdev, vfh, vfh->ctrl_handler,
> sd->v4l2_dev->mdev, arg);
>
> case VIDIOC_TRY_EXT_CTRLS:
> if (!vfh->ctrl_handler)
> return -ENOTTY;
> - return v4l2_try_ext_ctrls(vfh->ctrl_handler,
> + return v4l2_try_ext_ctrls(vdev, vfh->ctrl_handler,
> sd->v4l2_dev->mdev, arg);
>
> case VIDIOC_DQEVENT:
> diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
> index d63cf227b0ab..0e38a59c80dd 100644
> --- a/include/media/v4l2-ctrls.h
> +++ b/include/media/v4l2-ctrls.h
> @@ -1272,13 +1272,15 @@ int v4l2_g_ext_ctrls(struct v4l2_ctrl_handler *hdl, struct media_device *mdev,
> * v4l2_try_ext_ctrls - Helper function to implement
> * :ref:`VIDIOC_TRY_EXT_CTRLS <vidioc_g_ext_ctrls>` ioctl
> *
> + * @vdev: pointer to &struct video_device
> * @hdl: pointer to &struct v4l2_ctrl_handler
> * @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,
> +int v4l2_try_ext_ctrls(struct video_device *vdev,
> + struct v4l2_ctrl_handler *hdl,
> struct media_device *mdev,
> struct v4l2_ext_controls *c);
>
> @@ -1286,6 +1288,7 @@ int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl,
> * v4l2_s_ext_ctrls - Helper function to implement
> * :ref:`VIDIOC_S_EXT_CTRLS <vidioc_g_ext_ctrls>` ioctl
> *
> + * @vdev: pointer to &struct video_device
> * @fh: pointer to &struct v4l2_fh
> * @hdl: pointer to &struct v4l2_ctrl_handler
> * @mdev: pointer to &struct media_device
> @@ -1293,7 +1296,9 @@ int v4l2_try_ext_ctrls(struct v4l2_ctrl_handler *hdl,
> *
> * If hdl == NULL then they will all return -EINVAL.
> */
> -int v4l2_s_ext_ctrls(struct v4l2_fh *fh, struct v4l2_ctrl_handler *hdl,
> +int v4l2_s_ext_ctrls(struct video_device *vdev,
> + struct v4l2_fh *fh,
> + struct v4l2_ctrl_handler *hdl,
> struct media_device *mdev,
> struct v4l2_ext_controls *c);
>
> diff --git a/include/media/v4l2-ioctl.h b/include/media/v4l2-ioctl.h
> index 8533ece5026e..0ecd4e3e76a4 100644
> --- a/include/media/v4l2-ioctl.h
> +++ b/include/media/v4l2-ioctl.h
> @@ -612,6 +612,8 @@ 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 */
>
>
Regards,
Hans
