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-rw-r--r--Documentation/DocBook/v4l/vidioc-qbuf.xml24
1 files changed, 17 insertions, 7 deletions
diff --git a/Documentation/DocBook/v4l/vidioc-qbuf.xml b/Documentation/DocBook/v4l/vidioc-qbuf.xml
index ab691ebf3b93..f2b11f8a4031 100644
--- a/Documentation/DocBook/v4l/vidioc-qbuf.xml
+++ b/Documentation/DocBook/v4l/vidioc-qbuf.xml
@@ -64,7 +64,8 @@ zero to the number of buffers allocated with &VIDIOC-REQBUFS;
64contents of the struct <structname>v4l2_buffer</structname> returned 64contents of the struct <structname>v4l2_buffer</structname> returned
65by a &VIDIOC-QUERYBUF; ioctl will do as well. When the buffer is 65by a &VIDIOC-QUERYBUF; ioctl will do as well. When the buffer is
66intended for output (<structfield>type</structfield> is 66intended for output (<structfield>type</structfield> is
67<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant> or 67<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>,
68<constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE</constant>, or
68<constant>V4L2_BUF_TYPE_VBI_OUTPUT</constant>) applications must also 69<constant>V4L2_BUF_TYPE_VBI_OUTPUT</constant>) applications must also
69initialize the <structfield>bytesused</structfield>, 70initialize the <structfield>bytesused</structfield>,
70<structfield>field</structfield> and 71<structfield>field</structfield> and
@@ -75,7 +76,11 @@ supports capturing from specific video inputs and you want to specify a video
75input, then <structfield>flags</structfield> should be set to 76input, then <structfield>flags</structfield> should be set to
76<constant>V4L2_BUF_FLAG_INPUT</constant> and the field 77<constant>V4L2_BUF_FLAG_INPUT</constant> and the field
77<structfield>input</structfield> must be initialized to the desired input. 78<structfield>input</structfield> must be initialized to the desired input.
78The <structfield>reserved</structfield> field must be set to 0. 79The <structfield>reserved</structfield> field must be set to 0. When using
80the <link linkend="planar-apis">multi-planar API</link>, the
81<structfield>m.planes</structfield> field must contain a userspace pointer
82to a filled-in array of &v4l2-plane; and the <structfield>length</structfield>
83field must be set to the number of elements in that array.
79</para> 84</para>
80 85
81 <para>To enqueue a <link linkend="mmap">memory mapped</link> 86 <para>To enqueue a <link linkend="mmap">memory mapped</link>
@@ -93,10 +98,13 @@ structure the driver sets the
93buffer applications set the <structfield>memory</structfield> 98buffer applications set the <structfield>memory</structfield>
94field to <constant>V4L2_MEMORY_USERPTR</constant>, the 99field to <constant>V4L2_MEMORY_USERPTR</constant>, the
95<structfield>m.userptr</structfield> field to the address of the 100<structfield>m.userptr</structfield> field to the address of the
96buffer and <structfield>length</structfield> to its size. 101buffer and <structfield>length</structfield> to its size. When the multi-planar
97When <constant>VIDIOC_QBUF</constant> is called with a pointer to this 102API is used, <structfield>m.userptr</structfield> and
98structure the driver sets the <constant>V4L2_BUF_FLAG_QUEUED</constant> 103<structfield>length</structfield> members of the passed array of &v4l2-plane;
99flag and clears the <constant>V4L2_BUF_FLAG_MAPPED</constant> and 104have to be used instead. When <constant>VIDIOC_QBUF</constant> is called with
105a pointer to this structure the driver sets the
106<constant>V4L2_BUF_FLAG_QUEUED</constant> flag and clears the
107<constant>V4L2_BUF_FLAG_MAPPED</constant> and
100<constant>V4L2_BUF_FLAG_DONE</constant> flags in the 108<constant>V4L2_BUF_FLAG_DONE</constant> flags in the
101<structfield>flags</structfield> field, or it returns an error code. 109<structfield>flags</structfield> field, or it returns an error code.
102This ioctl locks the memory pages of the buffer in physical memory, 110This ioctl locks the memory pages of the buffer in physical memory,
@@ -115,7 +123,9 @@ remaining fields or returns an error code. The driver may also set
115<constant>V4L2_BUF_FLAG_ERROR</constant> in the <structfield>flags</structfield> 123<constant>V4L2_BUF_FLAG_ERROR</constant> in the <structfield>flags</structfield>
116field. It indicates a non-critical (recoverable) streaming error. In such case 124field. It indicates a non-critical (recoverable) streaming error. In such case
117the application may continue as normal, but should be aware that data in the 125the application may continue as normal, but should be aware that data in the
118dequeued buffer might be corrupted.</para> 126dequeued buffer might be corrupted. When using the multi-planar API, the
127planes array does not have to be passed; the <structfield>m.planes</structfield>
128member must be set to NULL in that case.</para>
119 129
120 <para>By default <constant>VIDIOC_DQBUF</constant> blocks when no 130 <para>By default <constant>VIDIOC_DQBUF</constant> blocks when no
121buffer is in the outgoing queue. When the 131buffer is in the outgoing queue. When the