I'm using Ubuntu 13.10 with GNOME 3.10 on a Packard Bell EasyNote-TK37 (Intel GM45 Express graphics), and I've had significant problems with my backlight.
Initially, upon booting the backlight would not turn on, but if I shone a light at the screen I could see that it was being drawn correctly. I solved the issue using the commands in the following post:
https://stackoverflow.com/questions/8380688/linux-ubuntu-11-04-install-backlight-wont-turn-on
However, this didn't completely solve all issues. When the laptop sleeps, it's backlight turns off. This can be mitigated by setting the timer very high for sleeping, but when I lock the laptop the backlight still turns off, and will not turn back on.
Is there any way to force the backlight to remain on permanently?
Caffeine seems to fit that requirement, but it isn't working for me, at least on the current version of Ubuntu. A bash script would be extremely helpful, since I could add that to my backup script for when I have to reinstall Ubuntu.
If any clarification is needed please leave a comment below. Thanks.