User:MartinDengler
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About Me
I program for a living. I got an XO to support the OLPC project and have a laptop for daily use.
I work with python and Fedora a lot.
kernel module building for compcache
To build a kernel module on a joyride XO, ensure you have make and gcc (yum -y install make gcc should do it) and then try:
#get joyride kernel-devel rpm
wget http://dev.laptop.org/~dilinger/stable/kernel-devel-2.6.22-20080408.1.olpc.de2a86ff3b60edc.i586.rpm
sudo rpm -ivh kernel-devel-2.6.22-20080408.1.olpc.de2a86ff3b60edc.i586.rpm
sudo cp -af /boot/* /versions/boot/current/boot/
#get compcache
wget http://compcache.googlecode.com/files/compcache-0.3.tar.gz
tar xzf compcache-0.3.tar.gz
cd compcache-0.3
make
#use it
sudo ./use_compcache.sh
XO/OLPC mini-projects
I'm interested in helping with:
* Implementing ebook mode (Trac #2954) * Sugar grabs too many shortcut keys (Trac #4646) * and anything else that looks interesting
Ambient temperature tracking
bash-3.2$ cat /ofw/openprom/model ; echo CL1 Q2D13 Q2D bash-3.2$ cat /boot/olpc_build update.1 691 bash-3.2$ for f in /sys/class/power_supply/olpc-battery/temp* ; do (echo -e $f\\t ; cat $f) | paste - - ; done /sys/class/power_supply/olpc-battery/temp 2783 /sys/class/power_supply/olpc-battery/temp_ambient 3900
bemasc explained things on #olpc [I edited out background chatter]:
bemasc: "ambient" means "ambient in the case" bemasc: battery means in the battery compartment bemasc: the "ambient" thermometer is on the motherboard bemasc: not sure which chip bemasc: they were trying to place in the antenna bemasc: so that it would be far from the heat sources mtd: bemasc: so I guess if I want to know the temperature outside the case, the lower of the two numbers is closer to that (though still quite inaccurate) bemasc: the battery temp is closest, yeah bemasc: if you have another thermometer, you might consider trying to work out the offset and correct for it bemasc: it'll be different depending on whether the battery is charging or discharging, and how fast bemasc: and it'll take at least a few minutes to stabilize bemasc: so it's not easy, but it's also not impossible
Misc snippets to remember
Backlight and blurring switched off, makes some pdfs more readable:
su -c "echo 1 > /sys/devices/platform/dcon/output"
How to explicitly forget/add a WPA wireless network
If you want to forget/add a WPA wireless network explicitly, stop NetworkManager (/etc/init.d/NetworkManader stop) and edit
/home/olpc/.sugar/default/nm/networks.cfg
Screen battery status hint
Date: Sat, 5 Jan 2008 18:09:19 +0000
From: Martin Dengler <martin@martindengler.com>
Subject: Battery capacity in screen hardstatus line hint
To: devel@lists.laptop.org
[-- PGP output follows (current time: Sat 05 Jan 2008 06:23:51 PM GMT) --]
gpg: Signature made Sat 05 Jan 2008 06:09:19 PM GMT using DSA key ID 75C7D2F8
[GNUPG:] SIG_ID AwM6Me4nlHAq/mT0qRJbz79n4sk 2008-01-05 1199556559
[GNUPG:] GOODSIG 81B444DD75C7D2F8 martin@martindengler.com
gpg: Good signature from "martin@martindengler.com"
[GNUPG:] VALIDSIG 565C8F33ABF72DAA33DEB9CB81B444DD75C7D2F8 2008-01-05 1199556559 0 3 0 17 2 01 565C8F33ABF72DAA33DEB9CB81B444DD75C7D2F8
[GNUPG:] TRUST_ULTIMATE
[-- End of PGP output --]
[-- The following data is signed --]
Hi,
In case this is of use to anyone, I've put the battery capacity in my
xo screen instance's hardstatus line with this tiny script & screenrc
change:
---------- /home/olpc/bin/olpc_screen_status.sh
#!/bin/bash
# Author: Martin Dengler <martin@martindengler.com>
# idea from http://www.mail-archive.com/screen-users@gnu.org/msg00322.html
# based on battery info from olpc-logbat
#
B_INFO=/sys/class/power_supply/olpc-battery
while true
do
CAP=`cat $B_INFO/capacity`
echo b:$CAP%
sleep 60
done
----------
....screenrc change:
---------- /home/olpc/bin/.screenrc
# run command forever and assign most recent output to string escape %1`
backtick 1 0 0 /home/olpc/bin/olpc_screen_status.sh
# the ...%1`... part at the end is the important part
hardstatus alwayslastline "%{.bW}%-w%{.rW}%n %t%{-}%+w %=%{..G} %H %{..Y} %m/%d %C%a %1` "
----------
I'd be interested to know how to get at the ambient temperature sensor mentioned in section 2.4.1 of the CL1 hardware design specification PDF. I've had a look around /sys/class but nothing's jumped out at me.
Other useful OLPC hints
Activity Installation fu
From: Gary C Martin <gary@garycmartin.com>
Subject: Re: Playing w/ Activity packs in build 702
> Can anyone tell me how to install TamTam from scratch?
Not sure if this is the official way â but hidden in the update-
activities.py script from Bert Freudenberg is a very useful link to a
whole bunch of .xo builds, not all of which are available on the wiki
activities page (I'm not sure why). You can find .xo bundles for the
TamTam** activities here:
http://mock.laptop.org/repos/local.update1/XOS/index.html
** I believe the original TamTam activity is now considered old,
unsupported code, and has been split out into individual activities
called TamTamEdit, TamTamJam, TamTamMini, and TamTamSynthLab.
Once activities are installed, the new xo_get.py script (which
includes Bert's update-activities.py code), is very useful for keeping
all installed activities upgraded to the latest versions available.
You can download the xo-get.py file from:
http://wiki.laptop.org/go/Xo-get