diff mbox

VIDIOC_S_EXT_CTRLS

Message ID ADCA285CF15CD143BF1E6E2BAF6868AA0894EA4CD6@EAPEX1MAIL1.st.com (mailing list archive)
State New, archived
Headers show

Commit Message

Udit KUMAR Aug. 6, 2015, 5:22 a.m. UTC 
Hello 

When passing strings which has NULL in between, low level driver will not get full strings. 
Our typical use case is kernel level muxer, where "PMT" descriptor  is passed as strings, which will have NULL in between. 

In this case V4L2, copies the whole size and passing only stings to low level driver. 
If V4L2 sends size along with strings to low level driver then it will fix the problem and let low level driver to decide whether they want to use
size of strings or size. 

Below patch is proposed to fix such issues. 

 		char *string;
 	};
 	void *priv;
+	u32 size;
 };
 
 /** struct v4l2_ctrl_ref - The control reference.



Regards
Udit
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Comments

Hans Verkuil Aug. 6, 2015, 7:37 a.m. UTC | #1 
Hi Udit,

That's why it is called a 'string'. The NUL terminates the string.

If you want to pass character arrays, then use a V4L2_CTRL_TYPE_U8 array.

Regards,

	Hans

On 08/06/2015 07:22 AM, Udit KUMAR wrote:
> Hello 
> 
> When passing strings which has NULL in between, low level driver will not get full strings. 
> Our typical use case is kernel level muxer, where "PMT" descriptor  is passed as strings, which will have NULL in between. 
> 
> In this case V4L2, copies the whole size and passing only stings to low level driver. 
> If V4L2 sends size along with strings to low level driver then it will fix the problem and let low level driver to decide whether they want to use
> size of strings or size. 
> 
> Below patch is proposed to fix such issues. 
> 
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> index 7e38d59..bd3dc67 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -1166,10 +1166,12 @@ static int user_to_new(struct v4l2_ext_control *c,
>  	u32 size;
>  
>  	ctrl->is_new = 1;
> +	ctrl->size = c->size;
>  	switch (ctrl->type) {
>  	case V4L2_CTRL_TYPE_INTEGER64:
>  		ctrl->val64 = c->value64;
>  		break;
> diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
> index 47ada23..75ec59c 100644
> --- a/include/media/v4l2-ctrls.h
> +++ b/include/media/v4l2-ctrls.h
> @@ -152,6 +152,7 @@ struct v4l2_ctrl {
>  		char *string;
>  	};
>  	void *priv;
> +	u32 size;
>  };
>  
>  /** struct v4l2_ctrl_ref - The control reference.
> 
> 
> 
> Regards
> Udit
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> To unsubscribe from this list: send the line "unsubscribe linux-media" in
> the body of a message to majordomo@vger.kernel.org
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> 
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diff mbox

Patch

diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index 7e38d59..bd3dc67 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1166,10 +1166,12 @@  static int user_to_new(struct v4l2_ext_control *c,
 	u32 size;
 
 	ctrl->is_new = 1;
+	ctrl->size = c->size;
 	switch (ctrl->type) {
 	case V4L2_CTRL_TYPE_INTEGER64:
 		ctrl->val64 = c->value64;
 		break;
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index 47ada23..75ec59c 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -152,6 +152,7 @@  struct v4l2_ctrl {