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Subject: Re: [RFC PATCH v5 13/14] media: tegra-video: Add CSI MIPI pads
 calibration
From:   Sowjanya Komatineni <skomatineni@nvidia.com>
To:     Dmitry Osipenko <digetx@gmail.com>, <thierry.reding@gmail.com>,
        <jonathanh@nvidia.com>, <frankc@nvidia.com>, <hverkuil@xs4all.nl>,
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On 7/29/20 4:59 PM, Sowjanya Komatineni wrote:
>
> On 7/29/20 4:25 PM, Dmitry Osipenko wrote:
>> 28.07.2020 18:59, Sowjanya Komatineni =D0=BF=D0=B8=D1=88=D0=B5=D1=82:
>> ...
>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 ret =3D tegra_mipi_finish=
_calibration(csi_chan->mipi);
>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 if (ret < 0)
>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 d=
ev_err(csi_chan->csi->dev,
>>>>> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=
=C2=A0=C2=A0=C2=A0=C2=A0 "MIPI calibration failed: %d\n", ret);
>>>> Doesn't v4l2_subdev_call(OFF) need to be invoked here on error?
>>> Not required as on error streaming fails and runtime PM will turn off
>>> power anyway.
>> I see that camera drivers bump theirs RPM on s_stream=3D1, and thus,
>> s_stream=3D0 should be invoked in order to balance the RPM. What am I=20
>> missing?
>>
>> https://elixir.bootlin.com/linux/v5.8-rc4/source/drivers/media/i2c/ov274=
0.c#L634=20
>>
>
> Sensor drivers take care of RPM put when any failure happens during=20
> s_stream.
>
> So bridge driver don't have to call v4l2_subdev_call s_stream off=20
> incase if sensor subdev stream on fails.
>
>>> Also we only did csi subdev s_stream on and during sensor subdev
>>> s_stream on fail, actual stream dont happen and on tegra side frame
>>> capture by HW happens only when kthreads run.
>> Secondly, perhaps a failed calibration isn't a very critical error?
>> Hence just printing a warning message should be enough.
>
> Using dev_err to report calibration failure. Are you suggesting to use=20
> dev_warn instead of dev_err?
>
>>
>> Could you please make a patch that factors all ON/OFF code paths into a
>> separate functions? It's a bit difficult to follow the combined code,
>> especially partial changes in the patches. Thanks in advance!
>
> what do you mean by partial changes in patches?
>
> Can you please be more clear?

Also please specify what ON/OFF code paths you are referring to when you=20
say to move into separate functions?

>
> Thanks
>
> Sowjanya
>