[SOLVED] Brightness Key Levels T430

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https://bbs.archlinux.org – I tried doing acpi_osi="!Windows 2012" and this doesn't seem to work for me.  /sys/class/backlight/acpi_video0 exists, and brightness ranges from 0-15, but changing /sys/class/backlight/acpi_video0/brightness doesn't cause any change to the screen.Adding acpi_backlight=vendor causes it to change to thinkpad_screen from acpi_video0, but changing the brightness here doesn't affect anything either.Here's some relevant messages from my dmesg (this was captured with acpi_osi set and acpi_backlight not set):[    1.949590] thinkpad_acpi: detected a 8-level (HowTos)