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[Why] Set gamma not working on certain planes in MPO configuration Root cause is that video format (YUV-420) isn't allowed for IGAM where gamma is applied. Fix is not easy though: 1. allowing will not work because IGAM is before ICSC so RGB gamma would be applied on YUV pixels. 2. Moving OS gamma to DGAM or RGAM resulted in weird artifacts. Ultimately the root cause for these artifacts was due to handling end points and the fact that YUV->RGB conversion will frequently "overshoot" FP 1.0 value. DCE has a single end point and slope, so we would take max. In nightlight mode, blue channel is reduced, sometimes to flat 0 line, but red is virtually unchanged. Any "overshot" in blue will be clipped to 1 (max R,G,B) instead of max blue value. [How] Fortunately, this can be fixed on DCN where we have end point and slope for all three color channels. We cannot fix this problem on DCE. Other things fixed: - switch (back) to using RGAM for OS gamma instead of IGAM - add coeffs for 709 YUV->RGB (we used RGB->YUV for both conversions) - switch color temperature method to scaled bradford - otherwise we would have clipping problems that caused us to switch to IGAM for OS gamma in the first place. - comments and some minor improvements - there are some more issues but they will be addressed in separate commits. Signed-off-by: Krunoslav Kovac <Krunoslav.Kovac@amd.com> Reviewed-by: Aric Cyr <Aric.Cyr@amd.com> Acked-by: Leo Li <sunpeng.li@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.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.