I found a workaround in this related bug (for a very similar model of laptop, U9200): https://bugs.launchpad.net/ubuntu/+bug/352699
If /sys/module/video/parameters/brightness_switch_enabled is set to "N", then both brightness keys works as expected.
I found a workaround in this related bug (for a very similar model of laptop, U9200): /bugs.launchpad .net/ubuntu/ +bug/352699
https:/
If /sys/module/ video/parameter s/brightness_ switch_ enabled is set to "N", then both brightness keys works as expected.