I filed this bug: http://www.acpica.org/bugzilla/show_bug.cgi?id=931 and a bit later I read of a workaround in https://bugs.launchpad.net/ubuntu/+source/linux/+bug/518002 which is to add "acpi_osi=Linux" in the kernel command line. Then the brightness keys work, but there's no indicator popup window for the brightness, which is no big deal.
I filed this bug: http:// www.acpica. org/bugzilla/ show_bug. cgi?id= 931 /bugs.launchpad .net/ubuntu/ +source/ linux/+ bug/518002
and a bit later I read of a workaround in https:/
which is to add "acpi_osi=Linux" in the kernel command line.
Then the brightness keys work, but there's no indicator popup window for the brightness, which is no big deal.