I can't believe this is another 5+ year old bug that is still unresolved. I am experiencing this issue on Ubuntu/Xubuntu 11.04. The problem is that somehow dpms calls are being made to turn the backlight back on when a mouse event occurs, even though the lid is still shut.
I ran into some difficulty because the Ubuntu acpi-support scripts don't run if they detect a desktop (gnome/kde/xfce/etc) power-manager app running. It's a pain to have to kill those, because I lose all GUI-based power management (battery indicator, etc.) on my laptop. However, I got so fed up with this issue that I felt it was worth it to block the power-manager app so that acpid could run the show. In the end, the best solution I could find was to run lid.sh on a 1-minute recurring cron job. This forces the backlight off when the lid is closed and on when it's open. Not a very elegant solution, but at least I won't have to worry about burning out my laptop's monitor any more. Also vbetool did not work for me. Specifically, it was able to turn off the backlight, but was not able to turn it back on. After using vbetool to turn off the backlight, I had to switch to a text console and back to get the backlight to come back on! ** Also affects: xfce4-power-manager Importance: Undecided Status: New -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-power-manager in Ubuntu. https://bugs.launchpad.net/bugs/41994 Title: closed Laptop Lid to reliably keep Backlight off Status in The Dell Project: Invalid Status in Xfce4 Power Manager: New Status in “gnome-power-manager” package in Ubuntu: Confirmed Bug description: Currently, on Dapper Beta 1, closing the laptop lid causes the backlight to shut off. However, for example when moving the mouse the backlight switches back on, even if the lid is still closed. The backlight should stay off as long as the lid is closed. There is no sense in trying to read a display in a closed lid. I am using a Dell Latitude X1. To manage notifications about this bug go to: https://bugs.launchpad.net/dell/+bug/41994/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp