1 files changed, 14 insertions, 3 deletions
diff --git a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
index d4bbbb0c60e8..e62a15782790 100644
--- a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
+++ b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
@@ -59,9 +59,14 @@ When the I/O method is not supported the ioctl returns an ``EINVAL`` error
 code.
 
 Applications can call :ref:`VIDIOC_REQBUFS` again to change the number of
-buffers, however this cannot succeed when any buffers are still mapped.
-A ``count`` value of zero frees all buffers, after aborting or finishing
-any DMA in progress, an implicit
+buffers. Note that if any buffers are still mapped or exported via DMABUF,
+then :ref:`VIDIOC_REQBUFS` can only succeed if the
+``V4L2_BUF_CAP_SUPPORTS_ORPHANED_BUFS`` capability is set. Otherwise
+:ref:`VIDIOC_REQBUFS` will return the ``EBUSY`` error code.
+If ``V4L2_BUF_CAP_SUPPORTS_ORPHANED_BUFS`` is set, then these buffers are
+orphaned and will be freed when they are unmapped or when the exported DMABUF
+fds are closed. A ``count`` value of zero frees or orphans all buffers, after
+aborting or finishing any DMA in progress, an implicit
 :ref:`VIDIOC_STREAMOFF <VIDIOC_STREAMON>`.
 
 
@@ -112,6 +117,7 @@ any DMA in progress, an implicit
 .. _V4L2-BUF-CAP-SUPPORTS-USERPTR:
 .. _V4L2-BUF-CAP-SUPPORTS-DMABUF:
 .. _V4L2-BUF-CAP-SUPPORTS-REQUESTS:
+.. _V4L2-BUF-CAP-SUPPORTS-ORPHANED-BUFS:
 
 .. cssclass:: longtable
 
@@ -132,6 +138,11 @@ any DMA in progress, an implicit
     * - ``V4L2_BUF_CAP_SUPPORTS_REQUESTS``
       - 0x00000008
       - This buffer type supports :ref:`requests <media-request-api>`.
+    * - ``V4L2_BUF_CAP_SUPPORTS_ORPHANED_BUFS``
+      - 0x00000010
+      - The kernel allows calling :ref:`VIDIOC_REQBUFS` while buffers are still
+        mapped or exported via DMABUF. These orphaned buffers will be freed
+        when they are unmapped or when the exported DMABUF fds are closed.
 
 Return Value
 ============