[libcamera-devel] [PATCH] libcamera: ipu3: set V4L2_CID_INTEL_IPU3_MODE

[Jean-Michel Hautbois]

Hi Jacopo,

On 12/02/2021 13:54, Jacopo Mondi wrote:
> Hi Jean-Michel
> 
> On Wed, Feb 10, 2021 at 08:48:15PM +0100, Jean-Michel Hautbois wrote:
>> Hi Jacopo !
>>
>> On 10/02/2021 18:43, Jacopo Mondi wrote:
>>> Hi Jean-Michel
>>>
>>> On Tue, Feb 09, 2021 at 03:52:44PM +0100, Jean-Michel Hautbois wrote:
>>>> In order to get the stats back, the imgu subdev needs to have the
>>>> V4L2_CID_INTEL_IPU3_MODE control set.
>>>> Set it to video mode by default to get the stats at each frame.
>>>>
>>>> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois at ideasonboard.com>
>>>> ---
>>>>  src/libcamera/pipeline/ipu3/ipu3.cpp | 3 +--
>>>>  1 file changed, 1 insertion(+), 2 deletions(-)
>>>>
>>>> diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
>>>> index 61f7bf43..104cb532 100644
>>>> --- a/src/libcamera/pipeline/ipu3/ipu3.cpp
>>>> +++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
>>>> @@ -552,8 +552,7 @@ int PipelineHandlerIPU3::configure(Camera *camera, CameraConfiguration *c)
>>>>  	/* Apply the "pipe_mode" control to the ImgU subdevice. */
>>>>  	ControlList ctrls(imgu->imgu_->controls());
>>>>  	ctrls.set(V4L2_CID_IPU3_PIPE_MODE,
>>>> -		  static_cast<int32_t>(vfCfg ? IPU3PipeModeVideo :
>>>> -				       IPU3PipeModeStillCapture));
>>>> +		  static_cast<int32_t>(IPU3PipeModeVideo));
>>>
>>> I'm not opposed to this, and know we got to know what effect the pipe
>>> mode has, at least on statistics generation.
>>>
>>> I wonder what other features the StillCapture mode provides.
>>> Could you record with a todo that the usage of the pipe mode has to be
>>> clarified ?
>>
>> I don't know if we can know more than what is already in the kernel
>> documentation ?
>> https://linuxtv.org/downloads/v4l-dvb-apis/admin-guide/ipu3.html#running-mode-and-firmware-binary-selection
>>
>> I can add a TODO, in a v2 ?
> 
> Yes please, I still think we might want to use the StilCapture mode
> for, no surprise, still capture of raw frames, which, if I'm not
> mistaken should not involve the IPA and for which we don't need
> statistics.
> 
> If my understanding is correct, something along the lines of:
> /*
>  * \todo Set the ImgU pipe mode to 'Video' unconditionally to have statistics
>  * generated and re-consider if 'Still Capture' should be used for
>  * high quality RAW capture operations that do not involve the IPA.
>  */

Sounds great, v2 in a short time :-)

Thanks !
JM