This is a follow-up to my blog entry about Linux on the Asus UX305.
The guide for the majority of the changes listed below: https://www.reddit.com/r/linux/comments/3ia8ta/review_of_ubuntu_on_asus_ux305fa/
The screen resolution on the Asus UX305C is 3200x1800 on a 13.3" screen. Ubuntu isn't really aware of this, particularly if you're using Openbox. So I needed to do some font fixing. First was to open ~/.config/openbox/rc.xml and search for "ont" (which is what you do when you're lazy and don't know how "font" is capitalized). There are a number of instances where there are title and menu fonts at 8 and 9 points: I changed them all to 14. It's still a little small after a restart, but vastly improved.
I installed the Ubuntu xfonts-terminus package, and now always run my terminal as
xterm -fn terminus-32 (the largest font available in terminus). The next size down is terminus-28, which I found slightly too small.
With Firefox, I installed the "Theme Font & Size Changer" plugin, which allows you increase the size of fonts and user interface elements.
I installed cairo-dock as a launcher, but after a lot of fighting and instability, I've removed it. I've used it elsewhere previously and it's been fine (or at least reasonably stable after you finish tweaking it), but it was unstable and badly behaved in this context (Ubuntu 15.10 amd64, Asus UX305C).
I installed the powertop package, and it said that the main consumer of power was:
Usage Events/s Category Description 100.0% Device Audio codec hwC0D0: Realtek
... despite the fact that I wasn't playing any sound. So:
# echo 1 > /sys/module/snd_hda_intel/parameters/power_save
Installed the xbacklight package. Added two key setups to ~/.config/openbox/rc.xml:
<!-- For the Asus UX305C --> <keybind key="A-F5"> <action name="Execute"> <command>xbacklight -dec 5</command> </action> </keybind> <keybind key="A-F6"> <action name="Execute"> <command>xbacklight -inc 5</command> </action> </keybind>
So Alt-F5 and Alt-F6 (NOT the "fn" key, as Asus meant it to be) control the backlight (and only in Openbox).
I also installed laptop-mode-tools. From the reddit article:
The defaults in /etc/laptop-mode/laptop-mode.conf are fine, included the default of enabling the cpufreq module. This module disables itself in the presence of intel_pstate. Instead, edit the /etc/laptop-mode/conf.d/intel_pstate.conf - the defaults lock the CPU to 800MHz when on battery which make it unpleasantly slow and it doesn't really save any power. Instead, set *_PERF_MIN_PCT and *_PERF_MAX_PCT in both of the "On AC" options to 100. Set BATT_INTEL_PSTATE_PERF_MIN_PCT to 40 and BATT_INTEL_PSTATE_PERF_MAX_PCT to 100. Set all of the *_NO_TURBO to 0 - they don't matter on the Core M.
I didn't really follow his advice, going with more conservative numbers - although not so conservative as the defaults. And I left the turbo alone, as I think the Core M3 has turbo (although he may still be right). On his advice, I also added this:
laptop_mode auto force
to /etc/rc.local. In the same file I also added:
I should turn the bluetooth service off permanently, but this works for now (reddit guy claims that turning off bluetooth alone will save you an hour a day on the battery).
Edited /etc/default/grub and uncommented:
While it's true that this is uglier than the pretty stuff GRUB normally puts on screen, the high res makes it insanely slow drawing its screen on start-up and the fonts are unreadably tiny. This fixes both problems (by switching to text mode).
Turning down the screen brightness, switching music to power save, and turning off Bluetooth has taken me from an apparent battery life of about 3-3.5 hours up to about 7 hours. This is thoroughly UNtested, and based on the opinion of the computer's battery indicator. But it does appear to have helped considerably.