Re: [PATCH 3/3] [media] cobalt: Use v4l2_calc_timeperframe helper

Jose Abreu
2017-04-19T10:33:03Z

Hi Hans,

On 31-03-2017 09:59, Jose Abreu wrote:
> Hi Hans,
>
>
> On 30-03-2017 14:42, Hans Verkuil wrote:
>> Hi Jose,
>>
>> On 21/03/17 12:49, Jose Abreu wrote:
>>> Currently, cobalt driver always returns 60fps in g_parm.
>>> This patch uses the new v4l2_calc_timeperframe helper to
>>> calculate the time per frame value.
>> I can verify that g_parm works, so:
>>
>> Tested-by: Hans Verkuil <hans.verkuil@cisco.com>
>>
>> However, the adv7604 pixelclock detection resolution is only 0.25 MHz, so it
>> can't tell the difference between 24 and 23.97 Hz. I can't set the new
>> V4L2_DV_FL_CAN_DETECT_REDUCED_FPS flag there.
>>
>> It might be possible to implement this for the adv7842 receiver, I think that
>> that hardware is much more precise.
>>
>> I would have to try this, but that will have to wait until Friday next week.
> Thanks! Yes, maybe its better to test with a different receiver,
> if it has more precision then its great. Let me know if you need
> any help :)

Any news regarding this?

Best regards,
Jose Miguel Abreu

>
> Best regards,
> Jose Miguel Abreu
>
>> Regards,
>>
>> Hans
>>
>>> Signed-off-by: Jose Abreu <joabreu@synopsys.com>
>>> Cc: Carlos Palminha <palminha@synopsys.com>
>>> Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
>>> Cc: Hans Verkuil <hans.verkuil@cisco.com>
>>> Cc: linux-media@vger.kernel.org
>>> Cc: linux-kernel@vger.kernel.org
>>> ---
>>> drivers/media/pci/cobalt/cobalt-v4l2.c | 9 +++++++--
>>> 1 file changed, 7 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/media/pci/cobalt/cobalt-v4l2.c b/drivers/media/pci/cobalt/cobalt-v4l2.c
>>> index def4a3b..25532ae 100644
>>> --- a/drivers/media/pci/cobalt/cobalt-v4l2.c
>>> +++ b/drivers/media/pci/cobalt/cobalt-v4l2.c
>>> @@ -1076,10 +1076,15 @@ static int cobalt_subscribe_event(struct v4l2_fh *fh,
>>>
>>> static int cobalt_g_parm(struct file *file, void *fh, struct v4l2_streamparm *a)
>>> {
>>> + struct cobalt_stream *s = video_drvdata(file);
>>> + struct v4l2_fract fps;
>>> +
>>> if (a->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
>>> return -EINVAL;
>>> - a->parm.capture.timeperframe.numerator = 1;
>>> - a->parm.capture.timeperframe.denominator = 60;
>>> +
>>> + fps = v4l2_calc_timeperframe(&s->timings);
>>> + a->parm.capture.timeperframe.numerator = fps.numerator;
>>> + a->parm.capture.timeperframe.denominator = fps.denominator;
>>> a->parm.capture.readbuffers = 3;
>>> return 0;
>>> }
>>>