Sunday, March 28, 2010

High load on Acer Aspire 5738z with Ubuntu 9.10

There is a bug w.r.t to the graphic drivers for this laptop. This causes udev to take up quite a bit of CPU, making the laptop run hot.

The Ubuntu bug is here:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/440411

From the ubuntu bug, once can go look at the related kernel bug:
http://bugs.freedesktop.org/show_bug.cgi?id=23183

There seem to have been a resolution in the kernel but that got reverted since it was causing issues. So for now the problem remains.

For now I am killing udev to keep my laptop cool. Like so:

$ sudo /etc/init.d/udev stop

Thursday, March 18, 2010

Brigthness fix for Acer Aspire 5738z with Ubuntu 9.10

The brightness keys on this laptop (Fn + left/right arrow keys), do not work out of the box on Ubuntu. It does not work on 9.04 (Jaunty Jalopy) and continued to not work in 9.10 (Karmic Koala).

The work around for this is modifying your kernel command line to add "acpi_osi=Linux nomodeset acpi_backlight=vendor". One way to do this is to modify (or safer yet copy) a kernel entry in menu.1st file of the grub bootloader.

So for example if your boot directory is /boot/ then menu.1st is in /boot/grub/menu.1st.

I edited my latest kernel like so:
Old entry ->

title Ubuntu 9.10, kernel 2.6.31-20-generic
uuid some_id
kernel /boot/vmlinuz-2.6.31-20-generic
root=UUID=some_id ro quiet splash
initrd /boot/initrd.img-2.6.31-20-generic
quiet
New entry ->

title *Brigthness fix* Ubuntu 9.10, kernel 2.6.31-20-generic
uuid some_id
kernel /boot/vmlinuz-2.6.31-20-generic root=UUID=some_id
ro quiet splash acpi_osi=Linux nomodeset acpi_backlight=vendor
initrd /boot/initrd.img-2.6.31-20-generic
quiet

Taken from this thread:https://bugs.launchpad.net/ubuntu/+source/acpid/+bug/392948