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Subject[PATCH v2] media/doc: Allow sizeimage to be set by v4l clients
Date
This changes v4l2_pix_format and v4l2_plane_pix_format sizeimage
field description to allow v4l clients to set bigger image size
in case of variable length compressed data.

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
---
Documentation/media/uapi/v4l/pixfmt-v4l2-mplane.rst | 13 ++++++++++++-
Documentation/media/uapi/v4l/pixfmt-v4l2.rst | 11 ++++++++++-
2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/Documentation/media/uapi/v4l/pixfmt-v4l2-mplane.rst b/Documentation/media/uapi/v4l/pixfmt-v4l2-mplane.rst
index 5688c816e334..005428a8121e 100644
--- a/Documentation/media/uapi/v4l/pixfmt-v4l2-mplane.rst
+++ b/Documentation/media/uapi/v4l/pixfmt-v4l2-mplane.rst
@@ -31,7 +31,18 @@ describing all planes of that format.

* - __u32
- ``sizeimage``
- - Maximum size in bytes required for image data in this plane.
+ - Maximum size in bytes required for image data in this plane,
+ set by the driver. When the image consists of variable length
+ compressed data this is the number of bytes required by the
+ codec to support the worst-case compression scenario.
+
+ For uncompressed images the driver will set the value. For
+ variable length compressed data clients are allowed to set
+ the sizeimage field, but the driver may ignore it and set the
+ value itself, or it may modify the provided value based on
+ alignment requirements or minimum/maximum size requirements.
+ If the client wants to leave this to the driver, then it should
+ set sizeimage to 0.
* - __u32
- ``bytesperline``
- Distance in bytes between the leftmost pixels in two adjacent
diff --git a/Documentation/media/uapi/v4l/pixfmt-v4l2.rst b/Documentation/media/uapi/v4l/pixfmt-v4l2.rst
index 71eebfc6d853..0f7771151db9 100644
--- a/Documentation/media/uapi/v4l/pixfmt-v4l2.rst
+++ b/Documentation/media/uapi/v4l/pixfmt-v4l2.rst
@@ -89,7 +89,16 @@ Single-planar format structure
- Size in bytes of the buffer to hold a complete image, set by the
driver. Usually this is ``bytesperline`` times ``height``. When
the image consists of variable length compressed data this is the
- maximum number of bytes required to hold an image.
+ number of bytes required by the codec to support the worst-case
+ compression scenario.
+
+ For uncompressed images the driver will set the value. For
+ variable length compressed data clients are allowed to set
+ the sizeimage field, but the driver may ignore it and set the
+ value itself, or it may modify the provided value based on
+ alignment requirements or minimum/maximum size requirements.
+ If the client wants to leave this to the driver, then it should
+ set sizeimage to 0.
* - __u32
- ``colorspace``
- Image colorspace, from enum :c:type:`v4l2_colorspace`.
--
2.17.1
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