[libcamera-devel] [PATCH v4 3/9] libcamera: ipu3: Calculate number of buffers for ImgU

[Niklas Söderlund]

Decouple the number of buffers to allocate for the ImgU from the number
of buffers allocated for the CIO2. Instead of blindly following the CIO2
pick the maximum number of buffers requested for any stream facing
applications.

This is potentially wasteful, as each stream could allocate just as many
buffers as requested by the application instead of the maximum from the
set. But this is not more wasteful than what is already used by the
pipeline and should be fixed on top after the decoupling of the two
processing units.

Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
* Changes since v1
- Use std::max({ ... })
---
 src/libcamera/pipeline/ipu3/ipu3.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index db52bff46f45e55f..4fbc9ae54ddf049b 100644
--- a/src/libcamera/pipeline/ipu3/ipu3.cpp
+++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
@@ -735,7 +735,11 @@ int PipelineHandlerIPU3::allocateBuffers(Camera *camera)
 	if (ret < 0)
 		return ret;
 
-	bufferCount = ret;
+	bufferCount = std::max({
+		data->outStream_.configuration().bufferCount,
+		data->vfStream_.configuration().bufferCount,
+		data->rawStream_.configuration().bufferCount,
+	});
 
 	ret = imgu->allocateBuffers(data, bufferCount);
 	if (ret < 0) {
-- 
2.27.0