[libcamera-devel] [PATCH v2] ipa: ipu3: Consolidate querying of exposure and gain limits

[Umang Jain]

Hi,

On 3/3/22 19:52, Kieran Bingham wrote:
> Quoting Umang Jain (2022-03-03 14:14:06)
>> Hi,
>>
>> On 3/3/22 19:36, Kieran Bingham wrote:
>>> Quoting Umang Jain (2022-03-03 12:15:44)
>>>> Hi Kieran,
>>>>
>>>> On 3/3/22 17:17, Kieran Bingham wrote:
>>>>> Quoting Umang Jain (2022-03-01 07:59:19)
>>>>>> The exposure and gain limits are required for AGC configuration
>>>>>> handled in IPAIPU3::updateSessionConfiguration(), which is happening
>>>>>> already. Therefore the max/min private members in IPAIPU3 class for
>>>>>> exposure/gain serve no use except setting initial values of exposure_
>>>>>> and gain_ members.
>>>>>>
>>>>>> Drop the max/min private members from IPAIPU3 class and set initial
>>>>>> gain_ and exposure_ in  IPAIPU3::updateSessionConfiguration().
>>>>> Great, even better to drop them if they aren't used.
>>>>>
>>>>> This looks like we're on the path to removing the private variables for
>>>>> controls from the IPAIPU3 now, as they should all be stored in the
>>>>> context if there's any relationship with the algorithms.
>>>> yeah, we are on that path.
>>>>
>>>>> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
>>>>>
>>>>>> Signed-off-by: Umang Jain <umang.jain at ideasonboard.com>
>>>>>> ---
>>>>>> Changes in v2:
>>>>>>     - Split into separate patch
>>>>>>     - Prepped over "v4 ipa: ipu3: Misc clean up"
>>>>>>     - Don't include max/min exposure/gain members in
>>>>>>       IPASessionConfiguration, as they aren't used anywhere.
>>>>>> ---
>>>>>>     src/ipa/ipu3/ipu3.cpp | 26 ++------------------------
>>>>>>     1 file changed, 2 insertions(+), 24 deletions(-)
>>>>>>
>>>>>> diff --git a/src/ipa/ipu3/ipu3.cpp b/src/ipa/ipu3/ipu3.cpp
>>>>>> index 17324616..4b6852a7 100644
>>>>>> --- a/src/ipa/ipu3/ipu3.cpp
>>>>>> +++ b/src/ipa/ipu3/ipu3.cpp
>>>>>> @@ -167,11 +167,7 @@ private:
>>>>>>            /* Camera sensor controls. */
>>>>>>            uint32_t defVBlank_;
>>>>>>            uint32_t exposure_;
>>>>>> -       uint32_t minExposure_;
>>>>>> -       uint32_t maxExposure_;
>>>>>>            uint32_t gain_;
>>>>>> -       uint32_t minGain_;
>>>>>> -       uint32_t maxGain_;
>>>>> What's required to get rid of gain_, exposure_ and defVBlank_ from here
>>>>> too?
>>>> we can drop gain_, exposure_ and replace them with local vars, no issue
>>>> in that.
>>>>
>>>> defVBlank_ seems to be used IPAIPU3 class functions directly, but i
>>>> think we can move the defVBlank_ to JM's introduction of
>>>> IPASessionConfiguration.sensor structure
>>>>
>>>> With this plan i think we can drop these remaining private members from
>>>> IPAIPU3.
>>> Great, can easily be patches on top - doesn't need to be in this one.
>>
>> Ok.
>>
>> I have been thinking to introduce similar control-not-found error
>> checks(as removed in this patch) in updateSessionConfiguration(), since
>> we ll end up querying the exposure, gain, vblank controls there /only/ .
>> Might as well introduce the control-not-found error checks there.
> Aha, I assumed the checks were already there.
>
> We should certainly have checks that the controls are available,
> otherwise it can crash when it tries to access them.
>
> I wonder if we can skip the checks if they are Mandatory Controls as
> defined by the CameraSensor class though ...


Good point, like on a general level throughout the code-base should we 
add individuals checks for the mandatory controls ? or the mandatory 
control check in CameraSensor is a good gate-keeper to rely on..

By the way, I checked that V4L2_CID_GAIN isn't mandatory ... so I guess 
atleast for that, we need to.

>
> --
> Kieran
>
>
>>> --
>>> Kieran
>>>
>>>
>>>>> --
>>>>> Kieran
>>>>>
>>>>>
>>>>>>     
>>>>>>            /* Interface to the Camera Helper */
>>>>>>            std::unique_ptr<CameraSensorHelper> camHelper_;
>>>>>> @@ -192,10 +188,12 @@ void IPAIPU3::updateSessionConfiguration(const ControlInfoMap &sensorControls)
>>>>>>            const ControlInfo &v4l2Exposure = sensorControls.find(V4L2_CID_EXPOSURE)->second;
>>>>>>            int32_t minExposure = v4l2Exposure.min().get<int32_t>();
>>>>>>            int32_t maxExposure = v4l2Exposure.max().get<int32_t>();
>>>>>> +       exposure_ = minExposure;
>>>>>>     
>>>>>>            const ControlInfo &v4l2Gain = sensorControls.find(V4L2_CID_ANALOGUE_GAIN)->second;
>>>>>>            int32_t minGain = v4l2Gain.min().get<int32_t>();
>>>>>>            int32_t maxGain = v4l2Gain.max().get<int32_t>();
>>>>>> +       gain_ = minGain;
>>>>>>     
>>>>>>            /*
>>>>>>             * When the AGC computes the new exposure values for a frame, it needs
>>>>>> @@ -429,32 +427,12 @@ int IPAIPU3::configure(const IPAConfigInfo &configInfo,
>>>>>>             */
>>>>>>            ctrls_ = configInfo.sensorControls;
>>>>>>     
>>>>>> -       const auto itExp = ctrls_.find(V4L2_CID_EXPOSURE);
>>>>>> -       if (itExp == ctrls_.end()) {
>>>>>> -               LOG(IPAIPU3, Error) << "Can't find exposure control";
>>>>>> -               return -EINVAL;
>>>>>> -       }
>>>>>> -
>>>>>> -       const auto itGain = ctrls_.find(V4L2_CID_ANALOGUE_GAIN);
>>>>>> -       if (itGain == ctrls_.end()) {
>>>>>> -               LOG(IPAIPU3, Error) << "Can't find gain control";
>>>>>> -               return -EINVAL;
>>>>>> -       }
>>>>>> -
>>>>>>            const auto itVBlank = ctrls_.find(V4L2_CID_VBLANK);
>>>>>>            if (itVBlank == ctrls_.end()) {
>>>>>>                    LOG(IPAIPU3, Error) << "Can't find VBLANK control";
>>>>>>                    return -EINVAL;
>>>>>>            }
>>>>>>     
>>>>>> -       minExposure_ = itExp->second.min().get<int32_t>();
>>>>>> -       maxExposure_ = itExp->second.max().get<int32_t>();
>>>>>> -       exposure_ = minExposure_;
>>>>>> -
>>>>>> -       minGain_ = itGain->second.min().get<int32_t>();
>>>>>> -       maxGain_ = itGain->second.max().get<int32_t>();
>>>>>> -       gain_ = minGain_;
>>>>>> -
>>>>>>            defVBlank_ = itVBlank->second.def().get<int32_t>();
>>>>>>     
>>>>>>            calculateBdsGrid(configInfo.bdsOutputSize);
>>>>>> -- 
>>>>>> 2.31.1
>>>>>>