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dgokhale
August 23rd, 2010, 01:11 PM
Hi..

I recently installed 64 bit 10.04 on my Ideapad U460. Most things seem to work fine but I am unable to control the screen brightness by using the Fn key and the Arrow keys (as it can be in Windows.)

The brightness can however be controlled using the Gnome Brightness applet.

I have tried googling the issue but have not found any solutions.

Does anyone know how to get the Fn key going??

Regards

D

treesurf
August 24th, 2010, 03:47 AM
I am having the same problem with an Lenovo Y550.

dgokhale
August 24th, 2010, 12:57 PM
I have reported this problem as a bug in launchpad (Bug #623065 (https://bugs.launchpad.net/bugs/623065)).

It seems its an issue with the kernel not registering an event when those keys are pressed. I read that the issue is resolved in a 2.6.34 version of kernels that are yet to be released... Will try an install one and post an update

treesurf
August 27th, 2010, 12:46 AM
Let us know if you have any success with any of the newer kernels.

dgokhale
August 27th, 2010, 09:48 AM
I installed the 2.6.35-rc1-lucid kernel (http://kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.35-rc1-lucid/) and that seems to solve the problem. I checked for the keymap and scan code and the FN+Up/Down keys do not register any scan code but the event is registered as an acpi_event.

Is there anything I can do to narrow down the problem to a specific program / module etc?

Also can somebody check if what I have done resolves the problem on other Ideapad laptops?

treesurf
August 28th, 2010, 05:11 PM
How do you go about installing that kernel? Also, isn't there a backported version of the Maverick kernel that's available to install through a ppa? Just wondering which route would be safer and/or better supported.

dgokhale
August 31st, 2010, 09:13 AM
How do you go about installing that kernel?

Just follow the instructions given on this page (https://wiki.ubuntu.com/Kernel/MainlineBuilds) and you should be able to do it quite easily.



Also, isn't there a backported version of the Maverick kernel that's available to install through a ppa? Just wondering which route would be safer and/or better supported.

Haven't really explored that. i tried the release candidate of Maverick through a live CD (it had 2.6.34 kernel version) but the brightness control didn't work in that either.

Maybe need to start moving backwards and find the first kernel that makes it work and then look for the exact problem. Priam facie it seems to me that its an ACPI issue. Though maybe I'm just plain wrong!

treesurf
September 1st, 2010, 06:07 PM
Current backported kernel is 2.6.35. I will try it later today. Here is the PPA:

http://ppa.launchpad.net/kernel-ppa/ppa/ubuntu


By the way, what is the difference between the "generic" and "generic-pae" kernel packages?

treesurf
September 1st, 2010, 06:23 PM
Never mind, just did my own research to discover that PAE kernel is not necessary unless using over 4GB of RAM. I'll give the generic kernel a try.

treesurf
September 2nd, 2010, 03:25 AM
I'm now running kernel 2.6.35-19 and can confirm that my brightness function keys do work again on a Lenovo Y550.

dgokhale
September 2nd, 2010, 05:31 AM
I'm now running kernel 2.6.35-19 and can confirm that my brightness function keys do work again on a Lenovo Y550.

did you compile from source or got a deb package to install? and any idea on what has been patched such that it works?

treesurf
September 2nd, 2010, 02:40 PM
I installed a deb package from the maverick backport kernel PPA. Unfortunately, I have now discovered that suspend does not seem to work properly with this kernel.

I have no idea what was patched so that the brightness keys now work. I think the question really is what happened in the lucid kernel so that they DON'T work. I had no problem with brightness keys prior to lucid.

treesurf
September 3rd, 2010, 04:52 AM
And now, strangely, suspend seems to be working again with no problem.