Update - I just started 3.13.0-39-generic from Trusty (on which everything was OK). But now it doesn't work. I can control brightness before X is started, but when lighdm starts brightness control no longer works.
IMHO this is rather related to X server, not kernel, what do you think?
Update - I just started 3.13.0-39-generic from Trusty (on which everything was OK). But now it doesn't work. I can control brightness before X is started, but when lighdm starts brightness control no longer works.
IMHO this is rather related to X server, not kernel, what do you think?