Re: [PATCH] media: i2c: adv748x: fix HDMI field heights

From: Kieran Bingham
Date: Mon Jan 08 2018 - 13:06:07 EST


Hi Niklas,

On 08/01/18 17:56, Niklas SÃderlund wrote:
> Hi Kieran,
>
> Thanks for your patch.
>
> On 2018-01-08 17:39:30 +0000, Kieran Bingham wrote:
>> The ADV748x handles interlaced media using V4L2_FIELD_ALTERNATE field
>> types. The correct specification for the height on the mbus is the
>> image height, in this instance, the field height.
>>
>> The AFE component already correctly adjusts the height on the mbus, but
>> the HDMI component got left behind.
>>
>> Adjust the mbus height to correctly describe the image height of the
>> fields when processing interlaced video for HDMI pipelines.
>>
>> Fixes: 3e89586a64df ("media: i2c: adv748x: add adv748x driver")
>> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
>> ---
>> drivers/media/i2c/adv748x/adv748x-hdmi.c | 4 ++++
>> 1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/media/i2c/adv748x/adv748x-hdmi.c b/drivers/media/i2c/adv748x/adv748x-hdmi.c
>> index 4da4253553fc..0e2f76f3f029 100644
>> --- a/drivers/media/i2c/adv748x/adv748x-hdmi.c
>> +++ b/drivers/media/i2c/adv748x/adv748x-hdmi.c
>> @@ -105,6 +105,10 @@ static void adv748x_hdmi_fill_format(struct adv748x_hdmi *hdmi,
>>
>> fmt->width = hdmi->timings.bt.width;
>> fmt->height = hdmi->timings.bt.height;
>> +
>> + /* Propagate field height on the mbus for FIELD_ALTERNATE fmts */
>> + if (hdmi->timings.bt.interlaced)
>
> if (V4L2_FIELD_HAS_T_OR_B(fmt->field))
>
> Nit-picking but I would use the field here (which is set just above this
> in the same function) as it makes it more clear why the format is cut in
> half. I looked at the documentation for bt.interlaced and I'm not sure
> if it would be set to true for INTERLACED field formats when the height
> should not be halved? In this case it do not matter as
>
> fmt->field = hdmi->timings.bt.interlaced ?
> V4L2_FIELD_ALTERNATE : V4L2_FIELD_NONE;
>
> So I leave this up to you and feel free to add in either case.

In this instance, I chose to mirror the value(/code path) which explicitly sets
the V4L2_FIELD_ALTERNATE, rather than:
if (fmt->field == V4L2_FIELD_ALTERNATE ||
fmt->field == V4L2_FIELD_TOP ||
fmt->field == V4L2_FIELD_BOTTOM)

But perhaps we would never expect _TOP || _BOTTOM therefore

if (fmt->field == V4L2_FIELD_ALTERNATE)

might be perfectly suitable?

Actually - yes - I now agree. I'll respin.

--
Kieran

> Reviewed-by: Niklas SÃderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
>
>> + fmt->height /= 2;
>> }
>>
>> static void adv748x_fill_optional_dv_timings(struct v4l2_dv_timings *timings)
>> --
>> 2.7.4
>>
>