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3a0c991fe3
The backlight power state handling is supremely confusing. We have: - props.power, using FB_BLANK_* defines - props.fb_blank, using the same, but deprecated int favour of props.state - props.state, using the BL_CORE_* defines - and finally a bunch of backlight drivers treat brightness == 0 as off. But of course not all of them. This is way too much confusion to fix in a simple patch, but at least prevent more hilarity from spreading by removing the unused BL_CORE_* defines. I have no idea why exactly anyone would need that. Wrt the ideal state, we really just want a boolean state. The 4 power saving states that the fbdev subsystem uses are overkill in todays hw (this was only relevant for VGA and similar analog circuits like TV-out), the new drm atomic modeset api simplified even the uapi to a simple bool. And there was never a valid technical reason to have the intermediate fbdev power states for backlights (those really only can be either off or on). Cleanup motivated by Meghana's questions about all this. Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Jingoo Han <jingoohan1@gmail.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Lee Jones <lee.jones@linaro.org>
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.