From 1107999f7143dbbf6f0122778ee9b49b4bb13432 Mon Sep 17 00:00:00 2001 From: Naushir Patuck Date: Tue, 25 Jul 2023 09:55:37 +0100 Subject: pipeline: rpi: Increase buffer import count to 32 Hardcode the maximum number of buffers imported to the V4L2 video device to 32. This only has a minor disadvantage of over-allocating cache slots and V4L2 buffer indexes, but does allow more headroom for using dma buffers allocated from outside of libcamera. Signed-off-by: Naushir Patuck Reviewed-by: Jacopo Mondi Reviewed-by: Kieran Bingham --- src/libcamera/pipeline/rpi/common/rpi_stream.cpp | 36 ++++++++---------------- 1 file changed, 11 insertions(+), 25 deletions(-) (limited to 'src/libcamera/pipeline') diff --git a/src/libcamera/pipeline/rpi/common/rpi_stream.cpp b/src/libcamera/pipeline/rpi/common/rpi_stream.cpp index c158843c..4b20ac3f 100644 --- a/src/libcamera/pipeline/rpi/common/rpi_stream.cpp +++ b/src/libcamera/pipeline/rpi/common/rpi_stream.cpp @@ -8,6 +8,9 @@ #include +/* Maximum number of buffer slots to allocate in the V4L2 device driver. */ +static constexpr unsigned int maxV4L2BufferCount = 32; + namespace libcamera { LOG_DEFINE_CATEGORY(RPISTREAM) @@ -95,34 +98,17 @@ int Stream::prepareBuffers(unsigned int count) int ret; if (!(flags_ & StreamFlag::ImportOnly)) { - if (count) { - /* Export some frame buffers for internal use. */ - ret = dev_->exportBuffers(count, &internalBuffers_); - if (ret < 0) - return ret; - - /* Add these exported buffers to the internal/external buffer list. */ - setExportedBuffers(&internalBuffers_); - resetBuffers(); - } + /* Export some frame buffers for internal use. */ + ret = dev_->exportBuffers(count, &internalBuffers_); + if (ret < 0) + return ret; - /* We must import all internal/external exported buffers. */ - count = bufferMap_.size(); + /* Add these exported buffers to the internal/external buffer list. */ + setExportedBuffers(&internalBuffers_); + resetBuffers(); } - /* - * If this is an external stream, we must allocate slots for buffers that - * might be externally allocated. We have no indication of how many buffers - * may be used, so this might overallocate slots in the buffer cache. - * Similarly, if this stream is only importing buffers, we do the same. - * - * \todo Find a better heuristic, or, even better, an exact solution to - * this issue. - */ - if ((flags_ & StreamFlag::External) || (flags_ & StreamFlag::ImportOnly)) - count = count * 2; - - return dev_->importBuffers(count); + return dev_->importBuffers(maxV4L2BufferCount); } int Stream::queueBuffer(FrameBuffer *buffer) -- cgit v1.2.1