LCD display would not come back on (Edit: now with theory)

[K. Eng]

I was working on my ThinkPad earlier this afternoon and I went out to lunch around 1PM. I left my machine locked at my desk (windows key + L), but I don't remember if I turned the display off.

I came back around 3:10PM and the LCD display was off, so I hit spacebar to turn the display back on. Nothing. The machine was still working so I started hitting keys and clicking the buttons to try to get the display back, but it would not turn back on!

Finally I had to hit the power button to shut it down and then reboot the machine. The Windows event logger claims that nothing has been amiss recently. This has never happened to me before. Any ideas?

Edit - New theory

I mentioned this to my roommate, who insisted that Fn+F7 was the proper way to turn off a ThinkPad display and not Fn+F3. Hmm...

So I hit Fn+F7 and my monitor went off. If I had an external display attached, it would have activated the external display. And no matter what other keys I pressed, the LCD would not turn back on unless I toggled Fn+F7 again.

And then I had a thought. I am pretty sure I did not turn off the display on my ThinkPad before I went to lunch, and when I do turn off the dispay I use Fn+F3, and nothing else. When I came back, I was not able to turn the display on with any keys, yet the system was still running, and the Windows Event Logger indicates that there were no problems or alerts.

Fn+F7 is the only way to replicate my problem. There are 2 possibilities: (1) Software malfunction somehow caused the display to automatically stop outputting to the LCD and start outputting to the external VGA port. I believe this is highly unlikely since I have not experienced this before. (2) If I did not turn off my display, and my computer did not turn off my display, then someone else did...

Thoughts?

Edit - I left my ThinkPad running overnight with the display on and confirmed that the display will not automatically turn off. Grrrrrr

[sugo]

So did you hit Fn F7 before you went to lunch?

I remember reading something similar on a thinkpad, not sure if it's this forum.

You said you can reproduce the issue with Fn F7. How exactly? Does it do that all the time?

I no longer use Fn F3 to turn off screen (don't remember the issue I ran into). But suffice to say that Fn F3 does not behave exactly the same as ACPI screen off. I now use a utility Wizmo.exe instead.

[K. Eng]

No. I can't remember if I left my display on or off, but I never use Fn+F7 to turn the display off, only Fn+F3.

Using Fn+F7 to turn off the display requires using Fn+F7 to turn the display back on (the key combo cycles through the display modes: LCD only, VGA out only, and LCD & VGA on simultaneously).

If I'm in LCD only mode, and someone hits Fn+F7 to toggle it to VGA out only mode, I can't restore the LCD display unless I use Fn+F7. This was the problem I had yesterday when I came back from lunch - I couldn't get my LCD to display using any single key, and it never occured to me that someone might have turned off the display using Fn+F7.

I did not use Fn+F7. I have determined that this most likely was not a software malfunction.

This means someone was messing around with my ThinkPad while I was gone!

So did you hit Fn F7 before you went to lunch?

You said you can reproduce the issue with Fn F7. How exactly? Does it do that all the time?

[sugo]

That's great. In that case your T40 should be okay then. Next time it happens again you can try getting fingerprint from the F7 key

Perhaps Thinkpad HotKey Manager or ATI driver should disable the Fn F7 when Windows is locked (secured).