[PATCH] [RFC] libcamera: pipeline: Add h/v blanking delays

[Paul Elder]

Quoting Kieran Bingham (2025-05-13 19:43:12)
> The HBLANK and VBLANK control delays are not being accounted for in all
> of the libipa platforms. Update their delayed controls instantiation
> accordingly.

I thought hblank was a generally a read-only control?

> 
> In particular, update the RKISP1 VBLANK control delay to be marked as a
> priority control as well as setting the correct delay to align with the
> existing Raspberry Pi implementation.

Given that the priorityWrite docs says 

 * Typically set for the \a V4L2_CID_VBLANK control so that the device driver
 * does not reject \a V4L2_CID_EXPOSURE control values that may be outside of
 * the existing vertical blanking specified bounds, but are within the new
 * blanking bounds.

I suppose we do want this.

> 
> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> ---
> 
> Marking this as RFC because I haven't tested this or explored it yet -
> but as I was reviewing other parts of the code base - I noted that these
> are inconsistent across pipeline handlers - so lets figure out why and
> make sure all the pipeline handlers operate in the same way where
> possible.
> 
>  src/libcamera/pipeline/ipu3/ipu3.cpp         | 2 ++
>  src/libcamera/pipeline/mali-c55/mali-c55.cpp | 2 ++
>  src/libcamera/pipeline/rkisp1/rkisp1.cpp     | 3 ++-
>  src/libcamera/pipeline/simple/simple.cpp     | 2 ++
>  4 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
> index e31e3879dcc9..4cec22b01940 100644
> --- a/src/libcamera/pipeline/ipu3/ipu3.cpp
> +++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
> @@ -1082,6 +1082,8 @@ int PipelineHandlerIPU3::registerCameras()
>                 std::unordered_map<uint32_t, DelayedControls::ControlParams> params = {
>                         { V4L2_CID_ANALOGUE_GAIN, { delays.gainDelay, false } },
>                         { V4L2_CID_EXPOSURE, { delays.exposureDelay, false } },
> +                       { V4L2_CID_HBLANK, { delays.hblankDelay, false } },
> +                       { V4L2_CID_VBLANK, { delays.vblankDelay, true } },
>                 };
>  
>                 data->delayedCtrls_ =
> diff --git a/src/libcamera/pipeline/mali-c55/mali-c55.cpp b/src/libcamera/pipeline/mali-c55/mali-c55.cpp
> index a05e11fccf8d..7d052263b34d 100644
> --- a/src/libcamera/pipeline/mali-c55/mali-c55.cpp
> +++ b/src/libcamera/pipeline/mali-c55/mali-c55.cpp
> @@ -1607,6 +1607,8 @@ bool PipelineHandlerMaliC55::registerSensorCamera(MediaLink *ispLink)
>                 std::unordered_map<uint32_t, DelayedControls::ControlParams> params = {
>                         { V4L2_CID_ANALOGUE_GAIN, { delays.gainDelay, false } },
>                         { V4L2_CID_EXPOSURE, { delays.exposureDelay, false } },
> +                       { V4L2_CID_HBLANK, { delays.hblankDelay, false } },
> +                       { V4L2_CID_VBLANK, { delays.vblankDelay, true } },
>                 };
>  
>                 data->delayedCtrls_ =
> diff --git a/src/libcamera/pipeline/rkisp1/rkisp1.cpp b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> index 52633fe3cb85..6c5b81b9a2ba 100644
> --- a/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> +++ b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> @@ -1325,7 +1325,8 @@ int PipelineHandlerRkISP1::createCamera(MediaEntity *sensor)
>         std::unordered_map<uint32_t, DelayedControls::ControlParams> params = {
>                 { V4L2_CID_ANALOGUE_GAIN, { delays.gainDelay, false } },
>                 { V4L2_CID_EXPOSURE, { delays.exposureDelay, false } },
> -               { V4L2_CID_VBLANK, { 1, false } },

(This probably won't apply upstream as it was recently fixed to
{ V4L2_CID_VBLANK, { delays.vblankDelay, false } }, )


Paul

> +               { V4L2_CID_HBLANK, { delays.hblankDelay, false } },
> +               { V4L2_CID_VBLANK, { delays.vblankDelay, true } },
>         };
>  
>         data->delayedCtrls_ =
> diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
> index efb07051b175..fc88efc7a716 100644
> --- a/src/libcamera/pipeline/simple/simple.cpp
> +++ b/src/libcamera/pipeline/simple/simple.cpp
> @@ -546,6 +546,8 @@ SimpleCameraData::SimpleCameraData(SimplePipelineHandler *pipe,
>         std::unordered_map<uint32_t, DelayedControls::ControlParams> params = {
>                 { V4L2_CID_ANALOGUE_GAIN, { delays.gainDelay, false } },
>                 { V4L2_CID_EXPOSURE, { delays.exposureDelay, false } },
> +               { V4L2_CID_HBLANK, { delays.hblankDelay, false } },
> +               { V4L2_CID_VBLANK, { delays.vblankDelay, true } },
>         };
>         delayedCtrls_ = std::make_unique<DelayedControls>(sensor_->device(), params);
>  
> -- 
> 2.49.0
>