I have also had this problem on my T61 (X3100 graphics), the fix is to add 'options thinkpad_acpi brightness_enable=1' to /etc/modprobe.d/options. brightness changing is very laggy/slow, but it works perfectly.
-- [REGRESSION] Impossible to change LCD brightness on Thinkpad R61/T61/X61 https://bugs.launchpad.net/bugs/198476 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
