What do you think about compat-wireless, iwl3945, & how does kernel find "updates" modules?
Paul Johnson
pauljohn32 at gmail.com
Tue Mar 11 18:22:23 UTC 2008
I'm making some progress on understanding my wireless troubles and the
iwl3945 driver for ipw3945.
In my adventure with the iwl3945 driver and the new-ish Fedora
kernels, I found this page by Bill Moss at Clemson. It explains some
details I've not found elsewhere.
http://www.ces.clemson.edu/linux/f8-nm-iwl3945-B.shtml
It mentions a project compat-wireless which has daily-updated code for
many different network kernel modules. Here's the tarball
http://linuxwireless.org/download/compat-wireless-2.6/compat-wireless-2.6.tar.bz2
The patches mentioned on Bill Moss's page are already applied in the
compat-wireless package that is online today. It is updated every
day.
I can verify that compat-wireless it is easy to install and, after
comparing the code day after day, it really does change every day.
I'm a little concerned that they don't have a marker in the file name
to indicate the date, because when you find one that works, you'd like
to be able to refer people to it.
A case in point. I have the Intel ipw3945 wireless in a Dell Laptop.
It hardly ever works under the iwl3945 driver in the 2.6.24 kernel
from Fedora, but I have had some luck experimenting with various koji
kernels. I never could figure out why it would change from day to
day, but I'm getting an idea that it traces back to the
compat-wireless changing from day to day.
Today, after updating the compat-wireless modules and restarting, it
actually found some networks and joined one. I almost fainted.
NetworkManager working? I had a dream like this last week, but a
twenty-five year old Farrah Fawcett was in it too, so I knew it was
not real. There's no Farrah today, so I'm guessing I just got lucky
with the iwl3945 from compat-wireless. :)
If you are one of the suffering iwl3945 users with the 2.6.24 kernel,
I wonder if the compat-wireless modules will help you as well? You
might as well try it. It is as easy as a "make" and "make install"
"make unload" and "make load". Or a restart. Their directions are
great.
I don't think you will see any new information in dmesg, the version
information is the same with either the kernel's iwl3945 driver or the
update. 1/2/26kds is the version:
$ dmesg | grep iwl
iwl3945: Intel(R) PRO/Wireless 3945ABG/BG Network Connection driver
for Linux, 1.2.26kds
iwl3945: Copyright(c) 2003-2007 Intel Corporation
iwl3945: Detected Intel Wireless WiFi Link 3945ABG
iwl3945: Tunable channels: 11 802.11bg, 13 802.11a channels
phy0: Selected rate control algorithm 'iwl-3945-rs'
But today it worked, and that's mainly what I'm here to say.
Here's my follow up question. When you run make install in the
compat-wireless package, it drops a bunch of kernel modules into your
/lib/modules hierearchy. It does not wipe out what you have, but
rather it drops them in a directory structure it creates and it runs
depmod for you. In my case today, the files are installed under:
/lib/modules/2.6.24.3-22.fc8/updates/drivers/net
I'm a little puzzled why or how the kernel (or is it depmod?) knows to
use the updates drivers before the ones provided by the kernel. See
what I mean, I have both sets still:
$ find . -name "mac8*"
./kernel/net/mac80211
./kernel/net/mac80211/mac80211.ko
./updates/net/mac80211
./updates/net/mac80211/mac80211.ko
PJ
--
Paul E. Johnson
Professor, Political Science
1541 Lilac Lane, Room 504
University of Kansas
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