c1ee92f94c
Adaptive Backlight Management (ABM) is a feature that reduces backlight level to save power, while increasing pixel contrast and pixel luminance to maintain readability and image quality. ABM will adjust in response to the pixel luminance of the displayed content. ABM is made available as a drm property on eDP monitors called "abm level", which ranges from 0 to 4. When this property is set to 0, ABM is off. Levels 1 to 4 represent different ranges of backlight reduction. At higher levels both the backlight reduction and pixel adjustment will be greater. ABM requires DMCU firmware, which is currently available for Raven ASICs only. If the feature does not work, please ensure your firmware is up to date. v2: Fix commit message, only attach property if DMCU loaded v3: Store ABM level in crtc state to accommodate dc v4: Fix ABM saving on dpms cycle Signed-off-by: David Francis <David.Francis@amd.com> Reviewed-by: Harry Wentland <harry.wentland@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.