For settings up RaLink drivers for your wireless device, please see a previous entry: RT61 / RT2×00 RaLink Linux Driver Installation

In many previous kernel versions, including 2.6.27, my wireless would randomly go down. I checked dmesg | tail and found that I received the following error:

[41884.647257] wlan0: authenticate with AP 00:15:e9:76:1a:ee
[41884.658208] wlan0: authenticated
[41884.658208] wlan0: associate with AP 00:15:e9:76:1a:ee
[41884.668257] wlan0: RX ReassocResp from 00:15:e9:76:1a:ee (capab=0x431 status=0 aid=5)
[41884.668257] wlan0: associated
[41892.844239] wlan0: no IPv6 routers present
[68822.729255] wlan0: No ProbeResp from current AP 00:15:e9:76:1a:ee - assume out of range

For more information, please see my posts in the following bug report:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/200500
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/200500/comments/35

Within the bug report, a link was referenced to modify the kernel, increasing the amount of time to wait for a response, so it doesn’t assume it’s out of range and disconnect. The problem is – the file to edit didn’t exist anymore in 2.6.27:

http://rt2x00.serialmonkey.com/phpBB/viewtopic.php?f=5&t=2081&p=30312&hilit=No+ProbeResp+from+current+AP#p30312

First, you must obtain your kernel source. In gentoo, emerge the vanilla or gentoo sources. In Ubuntu, run the following commands (taken and modified from https://help.ubuntu.com/community/Kernel/Compile):

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$ su
# (Enter root password - if it's not set, run "sudo su" instead)
$ apt-get install linux-source
$ cd /usr/src
$ tar xjvf /usr/src/linux-source-*.tar.bz2
$ cd linux-source-*
$ vi ./net/mac80211/mlme.c #or use your favorite text editor

In the file mlme.c, find the following line:

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#define IEEE80211_MONITORING_INTERVAL (2 * HZ)

Modify it so it looks like this (we’re changing the “2″ to “100″):

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#define IEEE80211_MONITORING_INTERVAL (100 * HZ)

Save and close the file. Let’s get to building it. With Gentoo, you would simply run “make && make modules_install”, navigate to “arch/your_arch/boot”, find the image, and copy it to /boot. Then modify GRUB/Lilo accordingly. Since Gentoo users probably know what they’re doing, I’ll focus on Ubuntu, which I recently figured out how to do via the above wiki. Ubuntu does it oddly.

Using the commands in the wiki, I had some trouble. It was trying to build using the “xen” archeticture – definatly not what I have. I wanted amd64 (which is x86_64 in the eyes of the kernel). So, I added the –arch option to the below commands. Be sure to specify YOUR architecture (such as i386). Also note the –apend-to-version line. This will append text to the kernel version (which’ll show up in uname -r). Remove it if you don’t want anything. If you do, modify the text in the command.

Multi-core/multiple processors: If you have multiple processors or cores (such as dual-core), type the following command before continuing, replacing the number with 1 + number of processors/cores. This will increase the compiling speed (trust me, you want that) by utilizing all available processors/cores. If you’re busy doing something else, you may wish not to set it, so your computer doesn’t slow down too much.

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# Do this only if you have multiple processors (see above paragraph)
$ export CONCURRENCY_LEVEL=3

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$ cp -vi /boot/config-`uname -r` .config #copy current configuration to use when building kernel
$ make-kpkg --arch=amd64 clean
$ fakeroot make-kpkg --arch=amd64 --initrd --append-to-version=-some-string-here kernel-image kernel-headers

Go grab something to eat, watch TV, throw pebbles at young children – something to pass the time. It’ll take a while.

After it is complete, in Ubuntu, this will have created *.deb files and placed them in the parent directory (in this case, /usr/src). Let’s install them!

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$ echo vesafb | sudo tee -a /etc/initramfs-tools/modules
$ echo fbcon | sudo tee -a /etc/initramfs-tools/modules
$ dpkg -i linux-*.deb

After that, check out the following link for building the restricted modules:
https://help.ubuntu.com/community/CustomRestrictedModules

Then, of course, modify GRUB to boot the new image. Good luck!