--- zzzz-none-000/linux-3.10.107/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml 2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/Documentation/DocBook/media/v4l/pixfmt-packed-rgb.xml 2021-02-04 17:41:59.000000000 +0000
@@ -15,9 +15,6 @@
per pixel. These are all packed-pixel formats, meaning all the data
for a pixel lie next to each other in memory.
- When one of these formats is used, drivers shall report the
-colorspace V4L2_COLORSPACE_SRGB.
-
- Bit 7 is the most significant bit. The value of a = alpha
-bits is undefined when reading from the driver, ignored when writing
-to the driver, except when alpha blending has been negotiated for a
-Video Overlay or
-Video Output Overlay or when alpha component has been configured
-for a Video Capture by means of V4L2_CID_ALPHA_COMPONENT
- control.
+ Bit 7 is the most significant bit.
+
+ The usage and value of the alpha bits (a) in the ARGB and ABGR formats
+ (collectively referred to as alpha formats) depend on the device type and
+ hardware operation. Capture devices
+ (including capture queues of mem-to-mem devices) fill the alpha component in
+ memory. When the device outputs an alpha channel the alpha component will
+ have a meaningful value. Otherwise, when the device doesn't output an alpha
+ channel but can set the alpha bit to a user-configurable value, the V4L2_CID_ALPHA_COMPONENT
+ control is used to specify that alpha value, and the alpha component
+ of all pixels will be set to the value specified by that control. Otherwise
+ a corresponding format without an alpha component (XRGB or XBGR) must be
+ used instead of an alpha format.
+
+ Output devices (including output queues
+ of mem-to-mem devices and video output overlay
+ devices) read the alpha component from memory. When the device processes the
+ alpha channel the alpha component must be filled with meaningful values by
+ applications. Otherwise a corresponding format without an alpha component
+ (XRGB or XBGR) must be used instead of an alpha format.
+
+ The XRGB and XBGR formats contain undefined bits (-). Applications,
+ devices and drivers must ignore those bits, for both capture and output
+ devices.<constant>V4L2_PIX_FMT_BGR24</constant> 4 × 4 pixel
@@ -512,16 +674,14 @@
</formalpara>
</example>
- <important>
- <para>Drivers may interpret these formats differently.</para>
- </important>
-
- <para>Some RGB formats above are uncommon and were probably
-defined in error. Drivers may interpret them as in <xref
- linkend="rgb-formats-corrected" />.</para>
+ <para>Formats defined in <xref linkend="rgb-formats-deprecated"/> are
+ deprecated and must not be used by new drivers. They are documented here for
+ reference. The meaning of their alpha bits (a) is ill-defined and
+ interpreted as in either the corresponding ARGB or XRGB format, depending on
+ the driver.</para>
- <table pgwide="1" frame="none" id="rgb-formats-corrected">
- <title>Packed RGB Image Formats (corrected)
+