[libcamera-devel] [PATCH v2 02/13] libcamera: ipu3: Import instead of allocate statistic buffers

[Niklas Söderlund]

Statistics buffers are not yet used by the IPU3 pipeline, they are never
queued to the video device or in any other way consumed. The kernel
driver will however not allow video streaming to start if buffers are
not either allocated or imported on the video device. Instead of
allocating the buffers wasting memory that is never used import buffers.

Signed-off-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>
---
 src/libcamera/pipeline/ipu3/ipu3.cpp | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/libcamera/pipeline/ipu3/ipu3.cpp b/src/libcamera/pipeline/ipu3/ipu3.cpp
index fba45935741e0e4e..405550b1302fb370 100644
--- a/src/libcamera/pipeline/ipu3/ipu3.cpp
+++ b/src/libcamera/pipeline/ipu3/ipu3.cpp
@@ -1135,11 +1135,13 @@ int ImgUDevice::allocateBuffers(IPU3CameraData *data, unsigned int bufferCount)
 	}
 
 	/*
-	 * Use for the stat's internal pool the same number of buffers as for
-	 * the input pool.
+	 * The kernel fails to start if buffers are not either imported or
+	 * allocated for the statisitcs video device. As statistics buffers are
+	 * not yet used by the pipeline import buffers to save memory.
+	 *
 	 * \todo To be revised when we'll actually use the stat node.
 	 */
-	ret = stat_.dev->allocateBuffers(bufferCount, &stat_.buffers);
+	ret = stat_.dev->importBuffers(bufferCount);
 	if (ret < 0) {
 		LOG(IPU3, Error) << "Failed to allocate ImgU stat buffers";
 		goto error;
-- 
2.27.0