Hans de Goede
93ec6f222c
platform/x86: x86-android-tablets: Fix backlight ctrl for Lenovo Yoga Tab 3 Pro YT3-X90F
Fix the maximum brightness being much too low on the Yoga Tab 3 Pro. The LP8557 backlight controller can either be configured to multiply its PWM input and the I2C register set level (requiring both to be at 100% for 100% output); or to only take the I2C register set level into account. Multiplying the 2 levels is useful because this will turn off the backlight when the panel goes off and turns off its PWM output. But on the YT3-X90F the panel's PWM output defaults to a duty-cycle of much less then 100%, severely limiting max brightness. In this case the LP8557 should be configured to only take the I2C register into account and the i915 driver must turn off the backlight separately using a VBT MIPI sequence to turn off the backlight. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Link: https://lore.kernel.org/r/20231104205828.63139-4-hdegoede@redhat.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.
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