I recently upgraded my laptop's 9.04 to 9.10
My laptop is a Lenovo3000 G410 Model 2049

After upgrading to 9.10, the Fn+Up and Fn+Down keys stopped working. When the
system boots up, the brightness is at its Full position which is very
discomforting to the eyes. I've tried mapping a different set of keys to
increase or decrease brightness. Even then I am not able to adjust the
brightness.

A google search suggests how to do it for a Samsung. I tried doing the same on
my Lenovo but still it is not working. I've been trying various methods for the
past two days in vain. Anybody knows what might be the problem? One of the
results suggests compile an older kernel which earlier worked with 9.04. How do
I do that?