32a1648aca
Add support for composing XRGB888 planes in addition to the ARGB8888 format. In the case of an XRGB plane at the top, the composition consists of copying the RGB values of a pixel from src to dst and clearing alpha channel, without the need for alpha blending operations for each pixel. Blend equations assume a completely opaque background, i.e., primary plane is not cleared before pixel blending but alpha channel is explicitly opaque (a = 0xff). Also, there is room for performance evaluation in switching pixel blend operation according to the plane format. v4: - clear alpha channel (0xff) after blend color values by pixel - improve comments on blend ops to reflect the current state - describe in the commit message future improvements for plane composition Signed-off-by: Melissa Wen <melissa.srw@gmail.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/07bcf4643d11da9480599fe1b165e478bff58b25.1619250933.git.melissa.srw@gmail.com
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.