Broadcom Wireless

2014-04-01T21:42:31Z

Beder:

[[Category:Tutorials]]
== Introduction ==

This tutorial is written for setting up wireless on Slackware on laptops with Broadcom wireless cards. It deals with installing Boradcom's official proprietary '''wl''' driver for Linux that includes support for Broadcom's BCM4311-, BCM4312-, BCM4313-, BCM4321-, BCM4322-, BCM43224-, and BCM43225-, BCM43227- and BCM43228-based hardware.

== Prerequisites ==

This tutorial assumes a full Slackware installation. There should also be a way to transfer files to the target laptop - it can either be a working internet connection using the laptop's ethernet card, '''or''' a different machine with internet access and a USB thumb drive to transfer the files.
The regular user account on the laptop must also be a part of the ''netdev'' group.

== Getting Started ==

The first thing is to check if the user is part of the ''netdev'' group :

<pre>groups</pre>

If the output does not contain <code>netdev</code>, then as <code>root</code>, enter the following command :

<pre>usermod -a -G netdev username</pre>

where <code>username</code> is the name of your user account.

== Installing the driver ==

=== Sbopkg method ===
If a working internet connection is available on the laptop (say a wired connection), use [http://sbopkg.org sbopkg] to install the drivers :
<pre>sbopkg -i broadcom-sta</pre>

=== Manual method ===
Navigate to the slackbuilds.org's [http://slackbuilds.org/result/?search=broadcom-sta&sv= broadcom-sta page] and build the package according to the [http://slackbuilds.org/howto/ instructions] given. Make sure to download the source code relevant to the architecture of your installation (32-bit or 64-bit).

=== Kernel upgrade ===

If at any point you upgrade your kernel, you will have to do this process again, because the module is compiled against the running kernel only.

== Blacklisting the b43 and ssb modules ==

The Broadcom's <code>wl</code> driver conflicts with the kernel's <code>b43</code> driver, so open up the <code>/lib/modprobe.d/blacklist.conf</code> using the text editor of your choice as <code>root</code> and add the following lines to it :

<pre>
blacklist ssb
blacklist b43
blacklist bcma
</pre>

== Final steps ==

At this point, reboot your machine. The drivers should be installed and work now. To test this, enter the <code>iwconfig</code> command. you should see an output like this :

<pre>
$ iwconfig
lo no wireless extensions.

eth1 IEEE 802.11 Nickname:"lapto"
Access Point: Not-Associated
Link Quality:5 Signal level:217 Noise level:199
Rx invalid nwid:0 invalid crypt:31 invalid misc:0

eth0 no wireless extensions.
</pre>

This output suggests that the drivers installed right and your wireless card is recognized as <code>eth1</code> by the kernel. Hooray!

If you still don't see the wireless extensions, check if any of the blacklisted modules are really not loaded:
<pre>
lsmod | grep ssb
lsmod | grep b43
lsmod | grep bcma
</pre>

None of this commands should return anything. If any of the modules are still loaded, remove them manually:
<pre>
rmmod ssb
rmmod b43
rmmod bcma
</pre>

You can also make sure that the "wl" module is properly loaded
<pre>
lsmod | grep wl
</pre>

If there is no output, you may load the "wl" module manually
<pre>
modprobe wl
</pre>

You can now either use the <code>iwconfig</code> tool to configure your wireless networks, '''or''' if you prefer to use a GUI, follow the next section for installing Wicd.

== Installing Wicd ==

To make management of wireless connections easier, we will install [http://wicd.sourceforge.net/ Wicd] network manager that provides a simple configuration GUI and system tray icon.

=== Using slackpkg ===

If a working internet connection is available on the laptop (say a wired connection), simply use <code>slackpkg</code> to install wicd :
<pre>slackpkg install wicd</pre>

=== Using package tarball ===

Download the <code>Wicd</code> package for your Slackware version from the ''extra/'' section of your preferred Slackware [http://slackware.osuosl.org/ mirror] and install using <code>installpkg</code>.

For example, on a 32-bit system running Slackware 13.37, as root:

<pre>
wget http://slackware.dreamhost.com/slackware/slackware-13.37/extra/wicd/wicd-1.7.0-i486-2.txz
installpkg ./wicd-1.7.0-i486-2.txz
</pre>

== Wicd usage ==
Start the Wicd daemon :

<pre>
/etc/rc.d/rc.wicd start
</pre>

Once its started, run <code>wicd-client</code> and configure the network to your liking.

=== Caveat ===
Wicd by default treats <code>wlan0</code> as the default wireless interface. Since the interface is <code>eth1</code> in our case, you might want to correct this in Wicd's Preferences.

=== User note ===
In order to access the wicd client utilities, your user must also be in the netdev group. Add your user to the netdev group, logout and login to make it effective, then you can run the wicd client utilities as your user.
For the CLI based tool, there is wicd-cli and wicd-curses. For the GUI client, ther is wicd-client and wicd-gtk.

Resource Limits

2013-01-02T01:35:09Z

Beder:

= Purpose =

This page does not attempt to explain the different types of system resource limits or when it is (or is not) appropriate to change them; see '''man ulimit''' and [[http://google.com Google]] for that discussion.

However, some users run into problems with the linux kernel's default limit settings, so we'll attempt to explain how to modify them to suit special needs.

= Overview =

The default settings provided by the kernel are sane values for most multi-user machines. Issuing the command '''ulimit -Hn''' should show the following:
user@host:~$ ulimit -Hn
1024
and '''ulimit -n''' should show this:
user@host:~$ ulimit -n
1024

The first command shows the hard limit set by the kernel, and the second command shows the soft limit set by the user. An unprivileged user can increase the soft limit (up to the hard limit value), and he is also able to lower the hard limit (but then is unable to increase it, as an unprivileged user cannot raise the hard limit at all).

There are some situations which might require a larger hard limit for users, and the obvious "solution" is to add a line in /etc/profile to increase it. However, this will not work, because normal users cannot increase their hard limits (as indicated above).

= Solution =

To increase the hard limits for users, you will need to create '''/etc/initscript''' and place appropriate commands inside it. The easiest way is to copy the file '''/sbin/initscript.sample''' to '''/etc/initscript''' and edit the copy, but you are certainly free to "roll your own."

Using the following '''/etc/initscript''' file:

PATH=/bin:/sbin:/usr/bin:/usr/sbin
export PATH

# Increase the hardlimit for open files
ulimit -Hn 4096

# Execute the program.
eval exec "$4"

You should get the following after a reboot:
user@host:~$ ulimit -Hn
4096

user@host:~$ ulimit -n
1024

Notice that the hardlimit is now 4096 (as specified in /etc/initscript), but the softlimit is still 1024. In other words, you will still need to use /etc/profile (or some other shell init file - see below for recommendation) to raise the desired users' softlimits. With some creative scripting, you can be more selective about which users have what limits.

Rather than editing the system /etc/profile, it's recommended to create a custom file in /etc/profile.d and make it executable. This way, you don't have to worry about trying to merge your changes to /etc/profile when doing Slackware upgrades to new versions.

= Other Resources =

* '''man initscript'''
* '''man ulimit'''

[[Category:Tutorials]]

SlackWiki - User contributions [en]

Broadcom Wireless

Resource Limits