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e4c8ae3e3d
Commite6bcca0890("backlight: pwm_bl: Switch to using "atomic" PWM API") removed the driver internal enabled tracking in favor of simply checking the pwm state. This can lead to issues as all of gpio-, regulator- and pwm-state are used to determine the initial state and the bootloader or kernel can leave them in an inconsistent state at boot. In my case on rk3399-kevin, the pwm backlight is build as module and the kernel disables the supply regulator as unused while keeping the pwm running thus pwm_bl calling pwm_backlight_power_off() during probe and creating an unmatched regulator-disable call, as it never got enabled from the pwm-bl before. To prevent these consistency issues, reintroduce the driver-internal tracking of the enabled state. Fixes:e6bcca0890("backlight: pwm_bl: Switch to using "atomic" PWM API") Signed-off-by: Heiko Stuebner <heiko@sntech.de> Acked-by: Thierry Reding <thierry.reding@gmail.com> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> 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
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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.