On 07/11/2022 08:20, Kun-Fa Lin wrote:
> Hi Hans,
>
> Thanks for the review.
>
>>
>> These functions are not usually present when capturing from video. You don't
>> have a choice w.r.t. resolution and fps, since that's determined by the
>> incoming video. I would drop support for this.
>
> Just to confirm, do you mean `npcm_video_enum_framesizes` and
> `npcm_video_enum_frameintervals` functions?
Right.
>
>
>>> + switch (ctrl->id) {
>>> + case V4L2_CID_DETECT_MD_MODE:
>>> + if (ctrl->val == V4L2_DETECT_MD_MODE_GLOBAL)
>>> + video->ctrl_cmd = VCD_CMD_OPERATION_CAPTURE;
>>> + else
>>> + video->ctrl_cmd = VCD_CMD_OPERATION_COMPARE;
>>> + break;
>>
>> Incorrect indentation for the 'break'.
>
> Will correct it.
>
>
>>> + v4l2_ctrl_new_std_menu(&video->ctrl_handler, &npcm_video_ctrl_ops,
>>> + V4L2_CID_DETECT_MD_MODE,
>>> + V4L2_DETECT_MD_MODE_REGION_GRID, 0,
>>> + V4L2_DETECT_MD_MODE_GLOBAL);
>>
>> Why is this driver using a control designed for motion detection devices?
>> That seems odd, and it looks like you are abusing this control to do something
>> else.
>
> The Video Capture/Differentiation (VCD) engine supports two modes:
> - COMPLETE (capture the next "complete frame" into memory)
> - DIFF (compare the incoming frame with the frame stored in memory,
> and updates the "diff frame" in memory)
>
> The purpose here is to provide a way for application to switch the
> COMPLETE/DIFF mode. Since I couldn't find an appropriate ioctl that is
> designed for this purpose, so I used VIDIOC_S_CTRL with control values
> of V4L2_DETECT_MD_MODE_GLOBAL (for COMPLETE) and
> V4L2_DETECT_MD_MODE_REGION_GRID (for DIFF). It would be appreciated if
> you could point me in the right direction.
This is very much a driver-specific control. So you have to make your
own.
This series is a good example on how to add a custom control:
https://lore.kernel.org/linux-media/20221028023554.928-1-jammy_huang@xxxxxxxxxxxxxx/
Driver-specific controls are fine, as long as they are properly documented.
>
>
>> When you post v7, please also include the output of v4l2-compliance to the
>> cover letter!
>> Make sure you compile v4l2-compliance from the v4l-utils git repo, do not
>> use a version from a distro, that will be too old.
>
> OK, I'll try to compile v4l2-compliance and include the output.
>
> Regards,
> Marvin
Regards,
Hans
