The code you've added is carefully checking the return pointer from 
pvr2_hdw_get_ctrl_v4l() yet the original code did not operate this way.  
The result is that now there's this "unbalanced" effect where it appears 
that the validity of the pvr2_ctrl instance is only checked on one side 
of the if-statement.  I would recommend instead to elevate the call to 
pvr2_hdw_get_ctrl_v4l() out of the if-statement - since in both cases 
it's being called the same way both times.  Then do the validity check 
in that one spot and that simplifies the if-statement all the way down 
to choosing between pvr2_ctrl_get_value() vs pvr2_ctrl_get_def().

It's not a correctness comment; what you have should work fine.  So I'm 
ack'ing this in any case:

Acked-By: Mike Isely <is...@pobox.com>

But you can do the above pretty easily & safely, and simplify it a bit 
further.

  -Mike


On Fri, 21 Aug 2015, 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 <ricardo.riba...@gmail.com>
> ---
>  drivers/media/usb/pvrusb2/pvrusb2-v4l2.c | 17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c 
> b/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
> index 1c5f85bf7ed4..43b2f2214798 100644
> --- a/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
> +++ b/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c
> @@ -628,6 +628,7 @@ static int pvr2_g_ext_ctrls(struct file *file, void *priv,
>       struct pvr2_v4l2_fh *fh = file->private_data;
>       struct pvr2_hdw *hdw = fh->channel.mc_head->hdw;
>       struct v4l2_ext_control *ctrl;
> +     struct pvr2_ctrl *cptr;
>       unsigned int idx;
>       int val;
>       int ret;
> @@ -635,8 +636,18 @@ static int pvr2_g_ext_ctrls(struct file *file, void 
> *priv,
>       ret = 0;
>       for (idx = 0; idx < ctls->count; idx++) {
>               ctrl = ctls->controls + idx;
> -             ret = pvr2_ctrl_get_value(
> +             if (ctls->which == V4L2_CTRL_WHICH_DEF_VAL) {
> +                     cptr = pvr2_hdw_get_ctrl_v4l(hdw, ctrl->id);
> +                     if (cptr)
> +                             pvr2_ctrl_get_def(cptr, &val);
> +                     else
> +                             ret = -EINVAL;
> +
> +
> +             } else
> +                     ret = pvr2_ctrl_get_value(
>                               pvr2_hdw_get_ctrl_v4l(hdw, ctrl->id), &val);
> +
>               if (ret) {
>                       ctls->error_idx = idx;
>                       return ret;
> @@ -658,6 +669,10 @@ static int pvr2_s_ext_ctrls(struct file *file, void 
> *priv,
>       unsigned int idx;
>       int ret;
>  
> +     /* Default value cannot be changed */
> +     if (ctls->which == V4L2_CTRL_WHICH_DEF_VAL)
> +             return -EINVAL;
> +
>       ret = 0;
>       for (idx = 0; idx < ctls->count; idx++) {
>               ctrl = ctls->controls + idx;
> 

-- 

Mike Isely
isely @ isely (dot) net
PGP: 03 54 43 4D 75 E5 CC 92 71 16 01 E2 B5 F5 C1 E8
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