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| -rw-r--r-- | Documentation/userspace-api/dma-buf-heaps.rst | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/Documentation/userspace-api/dma-buf-heaps.rst b/Documentation/userspace-api/dma-buf-heaps.rst index a0979440d2a4..5d68cab9ef13 100644 --- a/Documentation/userspace-api/dma-buf-heaps.rst +++ b/Documentation/userspace-api/dma-buf-heaps.rst @@ -16,16 +16,18 @@ following heaps: - The ``system`` heap allocates virtually contiguous, cacheable, buffers. - - The ``cma`` heap allocates physically contiguous, cacheable, - buffers. Only present if a CMA region is present. Such a region is - usually created either through the kernel commandline through the - ``cma`` parameter, a memory region Device-Tree node with the - ``linux,cma-default`` property set, or through the ``CMA_SIZE_MBYTES`` or - ``CMA_SIZE_PERCENTAGE`` Kconfig options. The heap's name in devtmpfs is - ``default_cma_region``. For backwards compatibility, when the - ``DMABUF_HEAPS_CMA_LEGACY`` Kconfig option is set, a duplicate node is - created following legacy naming conventions; the legacy name might be - ``reserved``, ``linux,cma``, or ``default-pool``. + - The ``default_cma_region`` heap allocates physically contiguous, + cacheable, buffers. Only present if a CMA region is present. Such a + region is usually created either through the kernel commandline + through the ``cma`` parameter, a memory region Device-Tree node with + the ``linux,cma-default`` property set, or through the + ``CMA_SIZE_MBYTES`` or ``CMA_SIZE_PERCENTAGE`` Kconfig options. Prior + to Linux 6.17, its name wasn't stable and could be called + ``reserved``, ``linux,cma``, or ``default-pool``, depending on the + platform. From Linux 6.17 onwards, the creation of these heaps is + controlled through the ``DMABUF_HEAPS_CMA_LEGACY`` Kconfig option for + backwards compatibility. + Naming Convention ================= |