Public bug reported:
Hi,
The installation of Linux on a brand new laptop is an incredible opportunity to
waste a lot of time...especially for a unrecoverable geek like me. I had a
strange behavior on my eeePC 1015PX with respect to power management and more
particularly with ASUS's Super Hybrid Engine (SHE). After having tried the very
ugly "Jupiter" (a software relying on mono...) I chose to let SHE be managed by
laptop-mode-tools, a very nice and heavily customizable package that optimizes
power management. I slightly modified
"/etc/laptop-mode/conf.d/eee-superhe.conf" to point to the right "cpufv" file
according to the new "eeepc-wmi" naming conventions :
SUPERHE_CONTROL_FILE=/sys/devices/platform/eeepc-wmi/cpufv
As I was using Matlab for doing intensive simulations, I noticed that,
while on AC, my EEEPC was very slow. So I launched Matlab's "bench"
command to perform some benchmarks and I was surprised to measure no
noticeable difference between AC and Battery modes.
So I started some investigations. I suspected a bad interference between
cpufreq and SHE. So I went in the /sys/devices/system/cpu/cpu0/cpufreq
directory and did a "cat scaling_max_freq" while on AC. I obtained
"1333000". On this platform it is not the maximum according to a "cat
cpuinfo_max_freq" giving "1667000". So I had the cause of my issue. Now
I had to find a fix. Before I need to find the cause of the cause. I
observed that, while on battery and so with the SHE powersave mode
engaged, doing an "echo 1667000 > scaling_max_freq" and after that an
"cat scaling_max_freq" gave me "1333000" instead of "1667000". So when
the SHE powersave mode (number 2) in selected, the maximum frequency is
saturated. Then I looked at the order of activation of the laptop-mode-
tools scripts in "/usr/share/laptop-mode-tools/modules". According to
the main script in "/usr/sbin" it is simply the alphabetical order. So
"cpufreq" is launched before "eee-superhe". And this is the core of the
problem.
1 Plug in the power
2 cpufreq tries to configure "scaling_max_freq" at "1667000 Hz" but is
saturated at "1333000 Hz" because there is still 2 in
"/sys/devices/platform/eeepc-wmi/cpufv".
3 eee-superhe switches "sys/devices/platform/eeepc-wmi/cpufv" from 2
(powersave) to 0 (performance).
So this fix is very easy : only change the first letter of the "eee-
superhe" script in order to be executed BEFORE "cpufreq".
sudo bash
cd /usr/share/laptop-mode-tools/modules
mv mv eee-superhe cp0_eee-superhe
Et voilà ! How to waste 2 hours ! I hope that this comment will save
your time.
** Affects: laptop-mode-tools (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/906335
Title:
EEE SHE and laptop-mode-tools adventures
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