Re: [PATCH v2 2/2] v4l: Add support for STD ioctls on subdev nodes

[Hans Verkuil <hverkuil@xs4all.nl>]

On 05/07/18 14:44, Mauro Carvalho Chehab wrote:
> Javier,
> 
> How standard settings work with the current OMAP3 drivers with tvp5150?

It looks like tvp5150 uses autodetect of the standard, which in general is
not a good thing to do since different standards have different buffer
sizes. But this chip can scale, so it might scale PAL to NTSC or vice versa
if the standard switches mid-stream. Or it only detects the standard when
it starts streaming, I'm not sure.

In any case, this is not normal behavior, for almost all analog video
receivers you need to be able to set the std explicitly.

Regards,

	Hans

> 
> Regards,
> Mauro
> 
> 
> Em Thu, 17 May 2018 16:30:16 +0200
> Niklas Söderlund         <niklas.soderlund+renesas@ragnatech.se> escreveu:
> 
>> There is no way to control the standard of subdevices which are part of
>> a media device. The ioctls which exists all target video devices
>> explicitly and the idea is that the video device should talk to the
>> subdevice. For subdevices part of a media graph this is not possible and
>> the standard must be controlled on the subdev device directly.
>>
>> Add four new ioctls to be able to directly interact with subdevices and
>> control the video standard; VIDIOC_SUBDEV_ENUMSTD, VIDIOC_SUBDEV_G_STD,
>> VIDIOC_SUBDEV_S_STD and VIDIOC_SUBDEV_QUERYSTD.
>>
>> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
>>
>> ---
>>
>> * Changes since v1
>> - Added VIDIOC_SUBDEV_ENUMSTD.
>> ---
>>  .../media/uapi/v4l/vidioc-enumstd.rst         | 11 ++++++----
>>  Documentation/media/uapi/v4l/vidioc-g-std.rst | 14 ++++++++----
>>  .../media/uapi/v4l/vidioc-querystd.rst        | 11 ++++++----
>>  drivers/media/v4l2-core/v4l2-subdev.c         | 22 +++++++++++++++++++
>>  include/uapi/linux/v4l2-subdev.h              |  4 ++++
>>  5 files changed, 50 insertions(+), 12 deletions(-)
>>
>> diff --git a/Documentation/media/uapi/v4l/vidioc-enumstd.rst b/Documentation/media/uapi/v4l/vidioc-enumstd.rst
>> index b7fda29f46a139a0..2644a62acd4b6822 100644
>> --- a/Documentation/media/uapi/v4l/vidioc-enumstd.rst
>> +++ b/Documentation/media/uapi/v4l/vidioc-enumstd.rst
>> @@ -2,14 +2,14 @@
>>  
>>  .. _VIDIOC_ENUMSTD:
>>  
>> -********************
>> -ioctl VIDIOC_ENUMSTD
>> -********************
>> +*******************************************
>> +ioctl VIDIOC_ENUMSTD, VIDIOC_SUBDEV_ENUMSTD
>> +*******************************************
>>  
>>  Name
>>  ====
>>  
>> -VIDIOC_ENUMSTD - Enumerate supported video standards
>> +VIDIOC_ENUMSTD - VIDIOC_SUBDEV_ENUMSTD - Enumerate supported video standards
>>  
>>  
>>  Synopsis
>> @@ -18,6 +18,9 @@ Synopsis
>>  .. c:function:: int ioctl( int fd, VIDIOC_ENUMSTD, struct v4l2_standard *argp )
>>      :name: VIDIOC_ENUMSTD
>>  
>> +.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_ENUMSTD, struct v4l2_standard *argp )
>> +    :name: VIDIOC_SUBDEV_ENUMSTD
>> +
>>  
>>  Arguments
>>  =========
>> diff --git a/Documentation/media/uapi/v4l/vidioc-g-std.rst b/Documentation/media/uapi/v4l/vidioc-g-std.rst
>> index 90791ab51a5371b8..8d94f0404df270db 100644
>> --- a/Documentation/media/uapi/v4l/vidioc-g-std.rst
>> +++ b/Documentation/media/uapi/v4l/vidioc-g-std.rst
>> @@ -2,14 +2,14 @@
>>  
>>  .. _VIDIOC_G_STD:
>>  
>> -********************************
>> -ioctl VIDIOC_G_STD, VIDIOC_S_STD
>> -********************************
>> +**************************************************************************
>> +ioctl VIDIOC_G_STD, VIDIOC_S_STD, VIDIOC_SUBDEV_G_STD, VIDIOC_SUBDEV_S_STD
>> +**************************************************************************
>>  
>>  Name
>>  ====
>>  
>> -VIDIOC_G_STD - VIDIOC_S_STD - Query or select the video standard of the current input
>> +VIDIOC_G_STD - VIDIOC_S_STD - VIDIOC_SUBDEV_G_STD - VIDIOC_SUBDEV_S_STD - Query or select the video standard of the current input
>>  
>>  
>>  Synopsis
>> @@ -21,6 +21,12 @@ Synopsis
>>  .. c:function:: int ioctl( int fd, VIDIOC_S_STD, const v4l2_std_id *argp )
>>      :name: VIDIOC_S_STD
>>  
>> +.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_G_STD, v4l2_std_id *argp )
>> +    :name: VIDIOC_SUBDEV_G_STD
>> +
>> +.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_S_STD, const v4l2_std_id *argp )
>> +    :name: VIDIOC_SUBDEV_S_STD
>> +
>>  
>>  Arguments
>>  =========
>> diff --git a/Documentation/media/uapi/v4l/vidioc-querystd.rst b/Documentation/media/uapi/v4l/vidioc-querystd.rst
>> index cf40bca19b9f8665..a8385cc7481869dd 100644
>> --- a/Documentation/media/uapi/v4l/vidioc-querystd.rst
>> +++ b/Documentation/media/uapi/v4l/vidioc-querystd.rst
>> @@ -2,14 +2,14 @@
>>  
>>  .. _VIDIOC_QUERYSTD:
>>  
>> -*********************
>> -ioctl VIDIOC_QUERYSTD
>> -*********************
>> +*********************************************
>> +ioctl VIDIOC_QUERYSTD, VIDIOC_SUBDEV_QUERYSTD
>> +*********************************************
>>  
>>  Name
>>  ====
>>  
>> -VIDIOC_QUERYSTD - Sense the video standard received by the current input
>> +VIDIOC_QUERYSTD - VIDIOC_SUBDEV_QUERYSTD - Sense the video standard received by the current input
>>  
>>  
>>  Synopsis
>> @@ -18,6 +18,9 @@ Synopsis
>>  .. c:function:: int ioctl( int fd, VIDIOC_QUERYSTD, v4l2_std_id *argp )
>>      :name: VIDIOC_QUERYSTD
>>  
>> +.. c:function:: int ioctl( int fd, VIDIOC_SUBDEV_QUERYSTD, v4l2_std_id *argp )
>> +    :name: VIDIOC_SUBDEV_QUERYSTD
>> +
>>  
>>  Arguments
>>  =========
>> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
>> index f9eed938d3480b74..27a2c633f2323f5f 100644
>> --- a/drivers/media/v4l2-core/v4l2-subdev.c
>> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
>> @@ -494,6 +494,28 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>>  
>>  	case VIDIOC_SUBDEV_S_DV_TIMINGS:
>>  		return v4l2_subdev_call(sd, video, s_dv_timings, arg);
>> +
>> +	case VIDIOC_SUBDEV_G_STD:
>> +		return v4l2_subdev_call(sd, video, g_std, arg);
>> +
>> +	case VIDIOC_SUBDEV_S_STD: {
>> +		v4l2_std_id *std = arg;
>> +
>> +		return v4l2_subdev_call(sd, video, s_std, *std);
>> +	}
>> +
>> +	case VIDIOC_SUBDEV_ENUMSTD: {
>> +		struct v4l2_standard *p = arg;
>> +		v4l2_std_id id;
>> +
>> +		if (v4l2_subdev_call(sd, video, g_tvnorms, &id))
>> +			return -EINVAL;
>> +
>> +		return v4l_video_std_enumstd(p, id);
>> +	}
>> +
>> +	case VIDIOC_SUBDEV_QUERYSTD:
>> +		return v4l2_subdev_call(sd, video, querystd, arg);
>>  #endif
>>  	default:
>>  		return v4l2_subdev_call(sd, core, ioctl, cmd, arg);
>> diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
>> index c95a53e6743cb040..03970ce3074193e6 100644
>> --- a/include/uapi/linux/v4l2-subdev.h
>> +++ b/include/uapi/linux/v4l2-subdev.h
>> @@ -170,8 +170,12 @@ struct v4l2_subdev_selection {
>>  #define VIDIOC_SUBDEV_G_SELECTION		_IOWR('V', 61, struct v4l2_subdev_selection)
>>  #define VIDIOC_SUBDEV_S_SELECTION		_IOWR('V', 62, struct v4l2_subdev_selection)
>>  /* The following ioctls are identical to the ioctls in videodev2.h */
>> +#define VIDIOC_SUBDEV_G_STD			_IOR('V', 23, v4l2_std_id)
>> +#define VIDIOC_SUBDEV_S_STD			_IOW('V', 24, v4l2_std_id)
>> +#define VIDIOC_SUBDEV_ENUMSTD			_IOWR('V', 25, struct v4l2_standard)
>>  #define VIDIOC_SUBDEV_G_EDID			_IOWR('V', 40, struct v4l2_edid)
>>  #define VIDIOC_SUBDEV_S_EDID			_IOWR('V', 41, struct v4l2_edid)
>> +#define VIDIOC_SUBDEV_QUERYSTD			_IOR('V', 63, v4l2_std_id)
>>  #define VIDIOC_SUBDEV_S_DV_TIMINGS		_IOWR('V', 87, struct v4l2_dv_timings)
>>  #define VIDIOC_SUBDEV_G_DV_TIMINGS		_IOWR('V', 88, struct v4l2_dv_timings)
>>  #define VIDIOC_SUBDEV_ENUM_DV_TIMINGS		_IOWR('V', 98, struct v4l2_enum_dv_timings)
> 
> 
> 
> Thanks,
> Mauro
>