diff options
Diffstat (limited to 'Documentation/DocBook/media/v4l/io.xml')
| -rw-r--r-- | Documentation/DocBook/media/v4l/io.xml | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml index 97a69bf6f3eb..a086a5db7a18 100644 --- a/Documentation/DocBook/media/v4l/io.xml +++ b/Documentation/DocBook/media/v4l/io.xml @@ -125,7 +125,7 @@ location of the buffers in device memory can be determined with the <structfield>m.offset</structfield> and <structfield>length</structfield> returned in a &v4l2-buffer; are passed as sixth and second parameter to the <function>mmap()</function> function. When using the multi-planar API, -struct &v4l2-buffer; contains an array of &v4l2-plane; structures, each +&v4l2-buffer; contains an array of &v4l2-plane; structures, each containing its own <structfield>m.offset</structfield> and <structfield>length</structfield>. When using the multi-planar API, every plane of every buffer has to be mapped separately, so the number of @@ -699,7 +699,12 @@ linkend="v4l2-buf-type" /></entry> buffer. It depends on the negotiated data format and may change with each buffer for compressed variable size data like JPEG images. Drivers must set this field when <structfield>type</structfield> -refers to an input stream, applications when it refers to an output stream.</entry> +refers to an input stream, applications when it refers to an output stream. +If the application sets this to 0 for an output stream, then +<structfield>bytesused</structfield> will be set to the size of the +buffer (see the <structfield>length</structfield> field of this struct) by +the driver. For multiplanar formats this field is ignored and the +<structfield>planes</structfield> pointer is used instead.</entry> </row> <row> <entry>__u32</entry> @@ -861,7 +866,11 @@ should set this to 0.</entry> <entry></entry> <entry>The number of bytes occupied by data in the plane (its payload). Drivers must set this field when <structfield>type</structfield> - refers to an input stream, applications when it refers to an output stream.</entry> + refers to an input stream, applications when it refers to an output stream. + If the application sets this to 0 for an output stream, then + <structfield>bytesused</structfield> will be set to the size of the + plane (see the <structfield>length</structfield> field of this struct) + by the driver.</entry> </row> <row> <entry>__u32</entry> |