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

[Umang Jain]

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.

>
> --
> 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
>>>>