[Bug 641660] [NEW] screen brightness problems on laptops with 10.04

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Well it seems that a lot of systems don't like to work with 10.04 when
you try to adjust the screen brightness......

Please read the comments below:

#1 
I have a Acer Aspire 5738Z laptop which I have just updated to 10.04. I cannot adjust the screen brightness either. On my machine the screen should be adjustable by using the window key and the left and right arrows. Pressing them does bring up a slider control which can be adjusted but it makes no difference to the actual brightness. The panel applet behaves exactly the same and makes not difference to the brightness.

#2
I have the same problem with my Dell Vostro 3500/NV310M/. (ubuntu 10.04, Nvidia driver 195.36.15)  The brightness of screen is set at 100%.I try to change it manually, "echo -n 30 >/proc/acpi/video/PEGP/LCD/brightness ". The value in ../brightness file was changed but the screen didn't change brightness. Sorry for my english. :)

#3
Yes, I have the same problem with my Toshiba T110 - the screen brightness should dim/brighten with the function keys but as with other comments, pressing them does bring up a slider control which can be adjusted but it makes no difference to the actual brightness.

#4
one more: i experience the problem with lucid on an asus k70ij function keys don't work, sometimes a slider appears after some seconds, but brightness remains at 100% neither the "echo -n 30 >/proc/acpi/video/PEGP/LCD/brightness" command works for me i found that "setpci -s 00:02.0 F4.B=11" does the job, but the problem is that in an unpredictable manner, brightness suddenly gets back to the maximum doh!

#5
Same here on a Dell Vostro 3500 with NVIDIA Driver Version 195.36.15 (Lucid Lynx 64bits). Is there any log/dump I could provide to help with this issue ?

#6
I add myself to this bunch. Exactly the same with Ubuntu 10.04 LTS 32-bit. It is a HP/Compaq 615. Changing the slider on the applet does not have any visible effect. The Function Keys controlling the brightness have no effect and fail to control the slider. The brightness is set to maximum. When plugging in the cable and removing it, thereby running on battery, the screen dims a step. Repeating the process the screen continues to being dimmed. There is no possibility to brighten it up again. So having done this a couple of times the screen is nearly dark. Rebooting the system, the screen brightness is back to maximum.
Can I help with some more info? BTW.: I am Linux newbie but with a high level of comprehension. Taught myself on computers since early 90's. Thank you anybody helping us out on this one.

#7
Yep, same here - a new duel boot 10.04 install on a Asus 1005PE and the screen brightness control does not work either.
Windows XP is happy and the GRUB loader works dandy and sees both installs but the Ubuntu desktop screen is very dark and if you try to adjust it, the screen brightness goes up and down and off in no real order - its not happy. I'd say its deff a bug! 10.04 Lynx is not happy but I ran 9.10 Koala on the Mini 1005PE for 9 months and it was great. Cheers' Dave

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: Opinion

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screen brightness problems on laptops with 10.04
https://bugs.launchpad.net/bugs/641660
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