Screen gets stuck in a dim setting after waking up

Question

I've got a laptop that I recently upgraded from Vista to Windows 7. It works a lot better now for a lot of things, but there's one problem I've had happen a few times that never happened under Vista.

When I put the system to sleep, then occasionally when I wake it up again, for no apparent reason, the screen's dim. Sometimes it's as if half the backlighting was turned off, and sometimes it's as if all the backlighting was turned off, all except for the mouse pointer, which remains as bright white as ever. Trying to change the screen's brightness does nothing, but rebooting fixes this.

Has anyone else seen this? Any ideas on what's causing it or how to make it stop happening?

Answer 1

I've encountered the same thing two or three times with a brand-new (~1 month old) Thinkpad T510 running dual-boot Windows/Linux. When it starts up in dimmed mode, the normal Windows brightness controls still work, so I can easily restore brightness that way, but Linux seems locked into treating the startup brightness as being the maximum possible - neither the installed brightness widget nor the keyboard brightness adjustment buttons will increase brightness beyond that point.

Although this hasn't happened often enough for me to be sure (yet), I suspect that the issue arises from shutting the machine down while the screen is dimmed, leading to the dimmed brightness being saved (presumably to BIOS, since both OSes are affected) and restored on the next boot.

Unfortunately, aside from making sure the screen isn't dimmed when shutting down, I have no other ideas on how to prevent this.

Answer 2

I can only presume that it's a bug. Whenever it happens I close then open the lid or whatever the equivalent of closing and opening the monitor then it manages to fix itself.