Re: [PATCH v2 06/10] usb/uvc: Support for V4L2_CTRL_WHICH_DEF_VAL

[Laurent Pinchart]

Hi Ricardo,

Thank you for the patch.

On Friday 21 August 2015 15:19:25 Ricardo Ribalda Delgado wrote:
> This driver does not use the control infrastructure.
> Add support for the new field which on structure
>  v4l2_ext_controls
> 
> Signed-off-by: Ricardo Ribalda Delgado 
> ---
>  drivers/media/usb/uvc/uvc_v4l2.c | 14 +-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c
> b/drivers/media/usb/uvc/uvc_v4l2.c index 2764f43607c1..e6d3a1bcfa2f 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -980,6 +980,7 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void
> *fh, struct uvc_fh *handle = fh;
>   struct uvc_video_chain *chain = handle->chain;
>   struct v4l2_ext_control *ctrl = ctrls->controls;
> + struct v4l2_queryctrl qc;
>   unsigned int i;
>   int ret;
> 
> @@ -988,7 +989,14 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file,
> void *fh, return ret;
> 
>   for (i = 0; i < ctrls->count; ++ctrl, ++i) {
> - ret = uvc_ctrl_get(chain, ctrl);
> + if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL) {
> + qc.id = ctrl->id;
> + ret = uvc_query_v4l2_ctrl(chain, );

The uvc_ctrl_begin() call above locks chain->ctrl_mutex, and 
uvc_query_v4l2_ctrl() will then try to acquire the same lock. That's not a 
good idea :-)

I propose moving the ctrls->which check before the uvc_ctrl_begin() call and 
implement it as

if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL) {
for (i = 0; i < ctrls->count; ++ctrl, ++i) {
struct v4l2_queryctrl qc = { .id = ctrl->id };

ret = uvc_query_v4l2_ctrl(chain, );
if (ret < 0) {
ctrls->error_idx = i;
return ret;
}

ctrl->value = qc.default_value;
}

return 0;
}

> + if (!ret)
> + ctrl->value = qc.default_value;
> + } else
> + ret = uvc_ctrl_get(chain, ctrl);
> +
>   if (ret < 0) {
>   uvc_ctrl_rollback(handle);
>   ctrls->error_idx = i;
> @@ -1010,6 +1018,10 @@ static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh
> *handle, unsigned int i;
>   int ret;
> 
> + /* Default value cannot be changed */
> + if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL)
> + return -EINVAL;
> +
>   ret = uvc_ctrl_begin(chain);
>   if (ret < 0)
>   return ret;

-- 
Regards,

Laurent Pinchart

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Re: [PATCH v2 06/10] usb/uvc: Support for V4L2_CTRL_WHICH_DEF_VAL

[Laurent Pinchart]

Hi Ricardo,

Thank you for the patch.

On Friday 21 August 2015 15:19:25 Ricardo Ribalda Delgado wrote:
> This driver does not use the control infrastructure.
> Add support for the new field which on structure
>  v4l2_ext_controls
> 
> Signed-off-by: Ricardo Ribalda Delgado 
> ---
>  drivers/media/usb/uvc/uvc_v4l2.c | 14 +-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c
> b/drivers/media/usb/uvc/uvc_v4l2.c index 2764f43607c1..e6d3a1bcfa2f 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -980,6 +980,7 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void
> *fh, struct uvc_fh *handle = fh;
>   struct uvc_video_chain *chain = handle->chain;
>   struct v4l2_ext_control *ctrl = ctrls->controls;
> + struct v4l2_queryctrl qc;
>   unsigned int i;
>   int ret;
> 
> @@ -988,7 +989,14 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file,
> void *fh, return ret;
> 
>   for (i = 0; i < ctrls->count; ++ctrl, ++i) {
> - ret = uvc_ctrl_get(chain, ctrl);
> + if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL) {
> + qc.id = ctrl->id;
> + ret = uvc_query_v4l2_ctrl(chain, );

The uvc_ctrl_begin() call above locks chain->ctrl_mutex, and 
uvc_query_v4l2_ctrl() will then try to acquire the same lock. That's not a 
good idea :-)

I propose moving the ctrls->which check before the uvc_ctrl_begin() call and 
implement it as

if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL) {
for (i = 0; i < ctrls->count; ++ctrl, ++i) {
struct v4l2_queryctrl qc = { .id = ctrl->id };

ret = uvc_query_v4l2_ctrl(chain, );
if (ret < 0) {
ctrls->error_idx = i;
return ret;
}

ctrl->value = qc.default_value;
}

return 0;
}

> + if (!ret)
> + ctrl->value = qc.default_value;
> + } else
> + ret = uvc_ctrl_get(chain, ctrl);
> +
>   if (ret < 0) {
>   uvc_ctrl_rollback(handle);
>   ctrls->error_idx = i;
> @@ -1010,6 +1018,10 @@ static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh
> *handle, unsigned int i;
>   int ret;
> 
> + /* Default value cannot be changed */
> + if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL)
> + return -EINVAL;
> +
>   ret = uvc_ctrl_begin(chain);
>   if (ret < 0)
>   return ret;

-- 
Regards,

Laurent Pinchart

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Re: [PATCH v2 06/10] usb/uvc: Support for V4L2_CTRL_WHICH_DEF_VAL

[Hans Verkuil]

Laurent, can you review this?

Regards,

Hans

On 08/21/2015 03:19 PM, Ricardo Ribalda Delgado wrote:
> This driver does not use the control infrastructure.
> Add support for the new field which on structure
>  v4l2_ext_controls
> 
> Signed-off-by: Ricardo Ribalda Delgado 
> ---
>  drivers/media/usb/uvc/uvc_v4l2.c | 14 +-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c 
> b/drivers/media/usb/uvc/uvc_v4l2.c
> index 2764f43607c1..e6d3a1bcfa2f 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -980,6 +980,7 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void 
> *fh,
>   struct uvc_fh *handle = fh;
>   struct uvc_video_chain *chain = handle->chain;
>   struct v4l2_ext_control *ctrl = ctrls->controls;
> + struct v4l2_queryctrl qc;
>   unsigned int i;
>   int ret;
>  
> @@ -988,7 +989,14 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void 
> *fh,
>   return ret;
>  
>   for (i = 0; i < ctrls->count; ++ctrl, ++i) {
> - ret = uvc_ctrl_get(chain, ctrl);
> + if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL) {
> + qc.id = ctrl->id;
> + ret = uvc_query_v4l2_ctrl(chain, );
> + if (!ret)
> + ctrl->value = qc.default_value;
> + } else
> + ret = uvc_ctrl_get(chain, ctrl);
> +
>   if (ret < 0) {
>   uvc_ctrl_rollback(handle);
>   ctrls->error_idx = i;
> @@ -1010,6 +1018,10 @@ static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh 
> *handle,
>   unsigned int i;
>   int ret;
>  
> + /* Default value cannot be changed */
> + if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL)
> + return -EINVAL;
> +
>   ret = uvc_ctrl_begin(chain);
>   if (ret < 0)
>   return ret;
> 

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Re: [PATCH v2 06/10] usb/uvc: Support for V4L2_CTRL_WHICH_DEF_VAL

[Hans Verkuil]

Laurent, can you review this?

Regards,

Hans

On 08/21/2015 03:19 PM, Ricardo Ribalda Delgado wrote:
> This driver does not use the control infrastructure.
> Add support for the new field which on structure
>  v4l2_ext_controls
> 
> Signed-off-by: Ricardo Ribalda Delgado 
> ---
>  drivers/media/usb/uvc/uvc_v4l2.c | 14 +-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c 
> b/drivers/media/usb/uvc/uvc_v4l2.c
> index 2764f43607c1..e6d3a1bcfa2f 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -980,6 +980,7 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void 
> *fh,
>   struct uvc_fh *handle = fh;
>   struct uvc_video_chain *chain = handle->chain;
>   struct v4l2_ext_control *ctrl = ctrls->controls;
> + struct v4l2_queryctrl qc;
>   unsigned int i;
>   int ret;
>  
> @@ -988,7 +989,14 @@ static int uvc_ioctl_g_ext_ctrls(struct file *file, void 
> *fh,
>   return ret;
>  
>   for (i = 0; i < ctrls->count; ++ctrl, ++i) {
> - ret = uvc_ctrl_get(chain, ctrl);
> + if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL) {
> + qc.id = ctrl->id;
> + ret = uvc_query_v4l2_ctrl(chain, );
> + if (!ret)
> + ctrl->value = qc.default_value;
> + } else
> + ret = uvc_ctrl_get(chain, ctrl);
> +
>   if (ret < 0) {
>   uvc_ctrl_rollback(handle);
>   ctrls->error_idx = i;
> @@ -1010,6 +1018,10 @@ static int uvc_ioctl_s_try_ext_ctrls(struct uvc_fh 
> *handle,
>   unsigned int i;
>   int ret;
>  
> + /* Default value cannot be changed */
> + if (ctrls->which == V4L2_CTRL_WHICH_DEF_VAL)
> + return -EINVAL;
> +
>   ret = uvc_ctrl_begin(chain);
>   if (ret < 0)
>   return ret;
> 

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