On 07/16/15 10:11, Laurent Pinchart wrote:
> Hi Hans,
> 
> On Thursday 16 July 2015 09:38:11 Hans Verkuil wrote:
>> On 07/15/15 23:05, Laurent Pinchart wrote:
>>> On Friday 12 June 2015 18:46:23 Ricardo Ribalda Delgado wrote:
>>>> Callback needed by ioctl VIDIOC_G_DEF_EXT_CTRLS as this driver does not
>>>> use the controller framework.
>>>>
>>>> Signed-off-by: Ricardo Ribalda Delgado <ricardo.riba...@gmail.com>
>>>> ---
>>>>
>>>>  drivers/media/usb/uvc/uvc_v4l2.c | 30 ++++++++++++++++++++++++++++++
>>>>  1 file changed, 30 insertions(+)
>>>>
>>>> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c
>>>> b/drivers/media/usb/uvc/uvc_v4l2.c index 2764f43607c1..e2698a77138a
>>>> 100644
>>>> --- a/drivers/media/usb/uvc/uvc_v4l2.c
>>>> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
>>>> @@ -1001,6 +1001,35 @@ static int uvc_ioctl_g_ext_ctrls(struct file
>>>> *file, void *fh,
>>>>    return uvc_ctrl_rollback(handle);
>>>>  }
>>>>
>>>> +static int uvc_ioctl_g_def_ext_ctrls(struct file *file, void *fh,
>>>> +                               struct v4l2_ext_controls *ctrls)
>>>> +{
>>>> +  struct uvc_fh *handle = fh;
>>>> +  struct uvc_video_chain *chain = handle->chain;
>>>> +  struct v4l2_ext_control *ctrl = ctrls->controls;
>>>> +  unsigned int i;
>>>> +  int ret;
>>>> +  struct v4l2_queryctrl qc;
>>>> +
>>>> +  ret = uvc_ctrl_begin(chain);
>>>
>>> There's no need to call uvc_ctrl_begin() here (and if there was, you'd
>>> have to call uvc_ctrl_rollback() or uvc_ctrl_commit() before returning).
>>>
>>>> +  if (ret < 0)
>>>> +          return ret;
>>>> +
>>>> +  for (i = 0; i < ctrls->count; ++ctrl, ++i) {
>>>> +          qc.id = ctrl->id;
>>>> +          ret = uvc_query_v4l2_ctrl(chain, &qc);
>>>> +          if (ret < 0) {
>>>> +                  ctrls->error_idx = i;
>>>> +                  return ret;
>>>> +          }
>>>> +          ctrl->value = qc.default_value;
>>>> +  }
>>>> +
>>>> +  ctrls->error_idx = 0;
>>>> +
>>>> +  return 0;
>>>> +}
>>>
>>> Instead of open-coding this in multiple drivers, how about adding a helper
>>> function to the core ? Something like (totally untested)
>>
>> It's only open-coded in drivers that do not use the control framework. For
>> drivers that use the control framework it is completely transparent.
> 
> Sure, but still, the same function is implemented several times while a 
> single 
> implementation could do. I'd prefer having it in the core until all (or all 
> but one) drivers are converted to the control framework.

There are only three drivers that need to implement this manually: uvc, saa7164
and pvrusb2. That's not enough to warrant moving this into the core.

One of these days I should sit down and convert saa7164 to the control 
framework.
That shouldn't be too difficult.

Regards,

        Hans

> 
>>> int v4l2_ioctl_g_def_ext_ctrls(struct file *file, void *fh,
>>>                                struct v4l2_ext_controls *ctrls)
>>> {
>>>     struct video_device *vdev = video_devdata(file);
>>>     unsigned int i;
>>>     int ret;
>>>     
>>>     for (i = 0; i < ctrls->count; ++i) {
>>>             struct v4l2_queryctrl qc;
>>>             
>>>             qc.id = ctrl->id;
>>>             ret = vdev->ioctl_ops->vidioc_queryctrl(file, fh, &qc);
>>>             if (ret < 0) {
>>>                     ctrls->error_idx = i;
>>>                     return ret;
>>>             }
>>>             ctrls->controls[i].value = qc.default_value;
>>>     }
>>>     ctrls->error_idx = 0;
>>>     
>>>     return 0;
>>> }
>>>
>>> The function could be called by v4l_g_def_ext_ctrls() when ops->
>>> vidioc_g_def_ext_ctrls is NULL.
> 
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