Ubuntu – Does the screen not return to full brightness when waking a Lenovo B570 from sleep mode


I have a Lenovo B570 laptop and have Ubuntu 11.10 installed. My problem is that when the screen is turned off through inactivity (set at 10 minutes in the settings), it is very difficult to reawaken the laptop because the screen doesn't 'wake up' to full brightness so that I can re-enter my password.

At first I thought that moving the mouse or pressing a keyboard button had no effect and the screen remained black, but in fact the screen does wake up and show the dialogue box to enter my password but the brightness has been turned down to the lowest level so if I squint very hard I can see the password entry dialogue box. But my hardware brightness keys (fn + up/down) do not work (though they work fine in every other circumstance).

I can unlock by entering my password 'blind' which unlocks the screen but leaves the brightness levels at the lowest possible, now the hardware brightness keys do work. Seems strange behaviour though. If I do a normal lock screen (Ctrl + Alt + L) there are no brightness problems so it must be something to do with the "turn screen off after 10 minutes" (possibly a fault with gnome-screensaver ?)

The same behaviour occurs when the laptop is on AC power or running from the battery. Having searched around the subject a bit more this question seems very similar, though there was no real answer proposed: https://askubuntu.com/questions/66932/screen-sleeps-but-cant-be-rewoken-on-an-hp-nx6310

Potentially as this may be a fault in the kernel might it be a good idea to update to the 12.04 version of the kernel? and if I needed to report this as a bug on Launchpad what package would I say was involved?

Thanks for any time and help.

Best Answer

I think you should file a bug in Launchpad in which you will explain the steps to reproduce the bug and specify that it happens only after wake from suspend. If you are unsure which package it affects, then for your kind of problem you can choose the kernel, as it is explained in this answer about how to report bugs.