Same problem on Ubuntu 12.04 (3.2.0-26-generic) and Thinkpad T500 echo 0 | sudo tee /sys/module/video/parameters/brightness_switch_enabled
or echo 4 > /proc/acpi/ibm/cmos echo 5 > /proc/acpi/ibm/cmos works -> ~9 brightness steps instead of ~5 steps dmesg: thinkpad_acpi: detected a 8-level brightness capable ThinkPad -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-power-manager in Ubuntu. https://bugs.launchpad.net/bugs/1000270 Title: Laptop backlight brightness increases/decreases 2 steps each time Status in “gnome-power-manager” package in Ubuntu: Confirmed Bug description: Hi, I have a Lenovo 3000 N200 laptop which uses a Nvidia Geforce Go 7300 graphics chip. I noticed this issue in Lubuntu 11.10 with the Nvidia binary driver and also after booting a Xubuntu 12.04 CD (using the Nouveau driver there I think). As far as I can remember, this issue wasn't present with either Ubuntu 8.04 or Xubuntu 9.10. The laptop has 8 possible backlight brightness settings. At the desktop, increasing or decreasing brightness (by pressing Fn-F10 or Fn-F11) causes the brightness to increase or decrease by 2 steps instead of 1. However, in text mode -- after switching with Ctrl- Alt-F1 -- changing brightness works as it should, in single steps. I noticed that the page http://forum.notebookreview.com/acer/434638-linux-acer-1410-1810tz-1810t.html mentions a fix for a similar issue with Acer laptops. That fix adds a line to /etc/rc.local: echo N > /sys/module/video/parameters/brightness_switch_enabled Applying that to my laptop fixed the screen brightness double-stepping at the desktop, so now changing brightness works as it should. However after doing that, the brightness cannot be changed at all when in text mode. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/1000270/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
