Dell Studio 1555 - brightness keys (ubuntu)
I have very strange problem with my notebook - Dell Studio 1555. I have installed on it Ubuntu 9.04. When it's booting the system, I can change the brightness by special keys normally. When Ubuntu is working, the keys usually work for about the first minute, and later they just stop functioning correctly - when I press them, there is only brightness icon shown and nothing else happens. I also noticed that it recognizes when I' ve closed the laptop if and only if the brightness control is working.
Can anyone help me?