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I picked up an hp dm3t laptop with intel HD graphics and installed ubuntu 10.10 64 bit on it. It works great -- the only problem is that the brightness controls on the keyboard don't work. The brightness is always at full. When I try to adjust it down, the indicator graphic indicates that it's going down but the actual brightness doesn't change. Is there anything that I can try to make this work? I'd really appreciate any help.

I asked this on superuser.com and someone commented that I should play around with the intel hd drivers. I'm a total noob -- how do I do that? What else can I try? I really don't want to go back to windows.

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2 Answers

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This seems to be a kernel bug.

You might be interested in reading this bug report, where an Ubuntu kernel developer posted a link to his PPA with a patched kernel (including steps on how to install it).

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This doesn't apply to my graphics driver – James Dec 30 '10 at 16:04
You have an Intel GMA 4500MHD and comments in this bug report suggest that the patched kernel fixes the very same problem with this GPU (eg. #111, #112). – htorque Dec 30 '10 at 17:54
Thanks so much! I'm having trouble finding steps on how to install it. The patched kernel is here: kernel.ubuntu.com/git?p=kamal/… ... I can't seem to find the directions on how to install it. Are they in the README inside of the download? If so, which section do I follow (there seem to be multiple options.) – James Dec 30 '10 at 20:10
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@James: You don't need to compile your own kernel. Just add the PPA to your system. Start a terminal and run sudo apt-add-repository ppa:kamalmostafa/linux-kamal-mjgbacklight, then sudo apt-get update and finally run the upgrade with sudo apt-get upgrade. As you can read in the above link to the PPA, you might need to add acpi_backlight=vendor to the linux-line of the grub entry for the new kernel (see the comments in this answer about how to add parameters to the kernel during boot). – htorque Dec 30 '10 at 22:08
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Try this.

sudo gedit /etc/default/grub

Change the line GRUB_CMDLINE_LINUX="" into GRUB_CMDLINE_LINUX="acpi_osi=Linux"

sudo update-grub

Restart your linux

Credit to this guy: http://livinginjava.blogspot.com/2010/11/ubuntu-1010-brightness-problem-in-acer.html

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This doesn't allow me to change the brightness. Also, the indicator that the brightness is being changed is gone. – James Dec 30 '10 at 15:57
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