I keep losing the ability to adjust screen brightness!

This has happened several times already and I'm not really sure what's causing it. Basically adjusting screen brightness with FN + F4/F5 works fine and then all of a sudden, it won't work. When I press FN + F4/F5, it shows the screen brightness adjuster thing on the screen, but it doesn't actually adjust it. If I reinstall the GPU driver(s), then it works again (even though it's the exact same driver). This time, I was adjusting the screen brightness while the computer was unplugged and I plugged it back in (It might have been while I was changing the brightness but I"m not sure) and then it stopped. What could the problem be? Is something corrupting the driver? It's really bugging me that this keeps happening.

 

Are you using official ATI drivers or Dell's drivers? Alot of times when you use official drivers you lose the ability to manually change the brightness. Happened on my Latitude 13.

 

Dell.
I always download drivers directly from Dell, mostly because I'm too lazy to find each and every driver for my system and Dell tells me what my system needs. :þ

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Well that's weird...I had to restart for Windows Update and all of a sudden I can change my brightness again...

EDIT: and it's back again....I have no idea what's causing this! Could it be a hardware issue that Dell can fix?

 

Just started getting this issue yesterday.

Whenever I try the Fn+F4/F5 while on the 6970m, the window thing pops up, but the gauge doesnt go any higher/lower. It's just blank and has no ticks to indicate the brightness(I hope you know what I mean). But when I switch to the integrated GPU, I can adjust brightness with Fn+F4/F5, and the ticks show correctly.

ADDITIONALLY, while on the 6970m, if I go to my power options (where you click on the battery/plug icon in the system tray, there's no option for "Adjust screen brightness." And when I actually open the power options window, the slider at the bottom isn't there. But whenever I switch to the integrated GPU, clicking adjust screen brightness will bring up the power options window, and the slider is there.

ODD and ANNOYING!

And every time I try reinstalling the graphics drivers (either stock Dell drivers or the Catalyst 12.11 beta drivers, I keep getting an error where it can't find the drivers, even though it just extracted them.

Oh, also, when I reboot the computer on the 6970m, it'll have the screen fully dimmed upon startup. And then I'll switch to the integrated GPU, and it'll be fully bright again (cuz of my last setting). Then if I switch to the 6970m, it'll be fully bright (but I still won't have the ability to adjust brightness again)...

Damnit!!!

 

I'm on a M17xR4 with a 680M and I have also ran into this issue many times. I'm running the latest Nvidia drivers but on a 120hz screen, with the stock Windows install from Dell. For me a simple reboot has solved the issue. I have also had my cooling fans kick on to full blast while on battery and stay stuck until I completly power down my system and plug it in.

 

I've also had this issue on my R4.

I have the 675m and Windows 7. However, I just reboot and it works again. It's not that often for me, tho.

 

If I restart the computer, the problem still persists... This GPU and the various drivers have been giving me lots of issues... I think I'm just gonna call it in for warranty service tomorrow, since I go the 3 year complete care thing... Think they'll just replace my GPU with a new one?

 

Have you tried switching to intel graphics then back to dedicated? With my 6990m I am unable to change brightness unless I am on intel graphics, this is due to the fact I am running one of the beta ATI drivers.

 

I find it unusual that this same issue is occuring on both nvidia and ati systems... and particurly on my 3D 120hz that has the intel graphics disabled full time

 

I think the nvidia users problem is different. I've seen this a lot through different drivers. Come out of a game and no way to adjust brightness. A restart always works but I found that if I go into the driver control panel and use the 'test stereoscopic 3D' option, when it exits the display brightness is workin gagain. Seems the display is left in 3D mode sometimes and the brightness does not work