#BRIGHTNESS KEY DRIVER#

thinkpad_acpi: Standard ACPI backlight interface available, not loading native one thinkpad_acpi: Disabling thinkpad-acpi brightness events by default.

#BRIGHTNESS KEY DRIVER#

thinkpad_acpi: This ThinkPad has standard ACPI backlight brightness control, supported by the ACPI video driver thinkpad_acpi: detected a 8-level brightness capable ThinkPad Here's some relevant messages from my dmesg (this was captured with acpi_osi set and acpi_backlight not set): 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.Īdding acpi_backlight=vendor causes it to change to thinkpad_screen from acpi_video0, but changing the brightness here doesn't affect anything either. I tried doing acpi_osi='!Windows 2012' and this doesn't seem to work for me. This might not be the best solution for anyone looking to script this functionality, or who wants to set a certain brightness on boot (using a tmpfiles.d conf file or a udev rule). I haven't tried using intel_backlight, but would like to note that changing the brightness with the now functional hot keys produces no change in the /sys directories. Thinkpad_screen was set to 0, so when I echoed the highest value (seven) into the brightness file it went up, but I couldn't get it to go back down via writing to the file. I too was able to have this fixed by telling the system to prefer thinkpad_acpi for this control (using the acpi_backlight=vendor kernel command line parameter).Įdit: BTW, with this parameter, I now no longer have acpi0_backlight, but rather intel_backlight and thinkpad_screen. At first I thought it might be because I had to have a new motherboard installed which came with a new bios version, but realized the the lts 3.4 kernel provided that functionality for me again. I too have a ThinkPad, though mine is an E430.

I too noticed that lately my backlight keys have stopped working with the latest kernels (namely the 3.8.* ones).

Brightness key