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Diffstat (limited to 'Documentation/userspace-api/media/v4l/buffer.rst')
| -rw-r--r-- | Documentation/userspace-api/media/v4l/buffer.rst | 35 |
1 files changed, 0 insertions, 35 deletions
diff --git a/Documentation/userspace-api/media/v4l/buffer.rst b/Documentation/userspace-api/media/v4l/buffer.rst index 52bbee81c080..856874341882 100644 --- a/Documentation/userspace-api/media/v4l/buffer.rst +++ b/Documentation/userspace-api/media/v4l/buffer.rst @@ -694,41 +694,6 @@ enum v4l2_memory - 4 - The buffer is used for :ref:`DMA shared buffer <dmabuf>` I/O. -.. _memory-flags: - -Memory Consistency Flags ------------------------- - -.. raw:: latex - - \small - -.. tabularcolumns:: |p{7.0cm}|p{2.1cm}|p{8.4cm}| - -.. cssclass:: longtable - -.. flat-table:: - :header-rows: 0 - :stub-columns: 0 - :widths: 3 1 4 - - * .. _`V4L2-MEMORY-FLAG-NON-COHERENT`: - - - ``V4L2_MEMORY_FLAG_NON_COHERENT`` - - 0x00000001 - - A buffer is allocated either in coherent (it will be automatically - coherent between the CPU and the bus) or non-coherent memory. The - latter can provide performance gains, for instance the CPU cache - sync/flush operations can be avoided if the buffer is accessed by the - corresponding device only and the CPU does not read/write to/from that - buffer. However, this requires extra care from the driver -- it must - guarantee memory consistency by issuing a cache flush/sync when - consistency is needed. If this flag is set V4L2 will attempt to - allocate the buffer in non-coherent memory. The flag takes effect - only if the buffer is used for :ref:`memory mapping <mmap>` I/O and the - queue reports the :ref:`V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS - <V4L2-BUF-CAP-SUPPORTS-MMAP-CACHE-HINTS>` capability. - .. raw:: latex \normalsize |