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When using brightness keys and backlight device's sysfs interface alternately, an incorrect input event might be generated for a brightness key press. Consider the following sequence of events: 1. Set backlight brightness to 6 using brightness keys. 2. Write 4 to /sys/class/backlight/fujitsu-laptop/brightness. 3. Press the "brightness up" key. The input event generated in this scenario would be KEY_BRIGHTNESSDOWN, because before step 3 brightness_level would still be at 6. As the new brightness level is established using GBLL, it would evaluate to 5 (SBLL/SBL2 sets it to 4 in step 2 and pressing the "brightness up" key increases it by 1). This in turn would cause acpi_fujitsu_bl_notify() to observe a 6 -> 5 change, i.e. a decrease in brightness, while screen brightness would in fact be increased. Fix this by updating brightness_level in set_lcd_level. Signed-off-by: Michał Kępień <kernel@kempniu.pl> Reviewed-by: Jonathan Woithe <jwoithe@just42.net> Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. 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.