05-23-2014 06:17 PM
I figured, being a laptop that is supposed to be available with Ubuntu, and approved by Ubuntu hardware certs, installing 14.04 would yield good results.
Everything except brightness control. Screen is maxed out, limiting battery life to 6 hours instead of 8-9. (I know, there are worse fates, but I'll be **bleep** if I am stuck with windows 8....)
I've tried many things. new kernels, RC kernels, catalyst drivers, etc. Nothing works.
Solved! Go to Solution.
05-28-2014 12:19 PM
08-21-2014 10:50 AM
In Ubuntu 14.04, adding those two kernel parameters to grub enabled brightness control via default hotkeys on my X140e.
08-16-2016 03:28 PM
That answer is correct, but lacking in detail for most users. To add kernel parameters you need to modify your grub file and then run update-grub.
First, start editing your grub file (with sudo):
sudo nano /etc/default/grub
Next look for the line that starts with GRUB_CMDLINE_LINUX_DEFAULT
On my x140e it looks like this:
Now add the kernel parameters to that line, adding a space, but within the quotes like this:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash thinkpad-acpi.brightness_enable=1 acpi_backlight=vendor"
Close the file, saving (ctrl-X, Y, enter)
Now run the update grub command so that the changes are incorporated on next boot:
Now restart the computer. My system is dual-boot and I find some of the hardware doesn't necessary switch 100% from one OS to the other, so you may be better off fully shutting down rather than just a reboot.