最近装gentoo还是遇到了很多困难。特别是无线网卡比较让人头疼。因为我这里只有无线的环境，无线网络无法驱动的话gentoo相当于就是个残废，上 不了网后面的基本上就免谈了。废话说到这里。我看了很多的资料，终于找到一个驱动无线网卡的方法。放在这里，相当于是做个笔记。

gentoo wiki上推荐了一个叫做iwlwifi的东东，好像是叫做intel wireless wifi。就是intel为了他自己的无线网卡开发的的一个开源驱动，适用于Intel PRO/Wireless 3945ABG/BG或者更新型号的intel无线网卡。这个驱动在2.6.24以后的内核中已经被包含进来了。如果你安装的发行版本是gentoo，并 且网卡是intel 3945abg/4956agn的话，那么你就接着看下面的内容吧。

相关阅读：

Gentoo 安装之intel GMA显卡篇 http://www.linuxidc.com/Linux/2012-03/56745.htm

首先是编译内核中需要主意的事项。

1.打开"mac80211"无线网络堆栈和加密选项(Cryptographic)的WEP,WAP和WPA2支持。

Linux Kernel Configuration:

Networking --->

[*] Networking support

Wireless --->

[*] Improved wireless configuration API

[*] nl80211 new netlink interface support

Generic IEEE 802.11 Networking Stack (mac80211)

[*] Cryptographic API --->

--- Cryptographic API

Cryptographic algorithm manager

SHA1 digest algorithm

SHA224 and SHA256 digest algorithm

ECB support

CBC support

PCBC support

AES cipher algorithms

ARC4 cipher algorithm

Michael MIC keyed digest algorithm     2.确认你已经在kernel中打开了"General Setup"的"Prompt for development and/or incomplete code/drivers"选项。否则你在kernel的配置中无法配置iwlwifi drivers选项。

Linux Kernel Configuration:

General Setup --->

[*] Prompt for development and/or incomplete code/drivers     3.等会你将为你的intel无线网卡安装对应的microcode.你可以通过portage来安装。iwlwifi驱动会在启动的时候装载这个micorcode。为了让它能正常工作起来，我们需要启用内核的firmware_loader支持:

Linux Kernel Configuration:

Device Drivers --->

Generic Driver Options --->

[*] Userspace firmware loading support注意：在后面的步骤中，强烈建议你把驱动编译为模块，因为驱动需要通过文件系统来加载网卡的固件。如果你把驱动编译到内核中，那么他将无法加载无线网卡的固件因为文件系统在内核加载之后才会被挂载上。

4.后面的设置对于2.6.25和2.6.26的内核就不一样了，需要分别设置

1)for linux kernel 2.6.25

如果你的无线网卡是Intel PRO/Wireless 3945AGB/BG,那么启用iwl3945的驱动.

Linux Kernel Configuration:

Device Drivers --->

[*] Network device support --->

[*] Wireless LAN --->

[*] Wireless LAN (IEEE 802.11)

Intel PRO/Wireless 3945ABG/BG Network Connection

[*] Enable Wireless QoS in iwl3945 driver

[*] Enable Spectrum Measurement in iwl3945 drivers或者你的无线网卡是Intel Wireless WiFi 4965AGN,那么启用iwl4965的驱动.

Linux Kernel Configuration:

Device Drivers --->

[*] Network device support --->

[*] Wireless LAN --->

[*] Wireless LAN (IEEE 802.11)

Intel Wireless WiFi 4965AGN

[*] Enable Wireless QoS in iwl4965 driver

[*] Enable 802.11n HT features in iwl4965 driver

[*] Enable Spectrum Measurement in iwl4965 driver

[*] Enable Sensitivity Calibration in iwl4965 driver

2)for linux kernel >>= 2.6.26

如果你的无线网卡是Intel PRO/Wireless 3945AGB/BG,那么启用iwl3945的驱动.

Linux Kernel Configuration:

Device Drivers --->

[*] Network device support --->

[*] Wireless LAN --->

[*] Wireless LAN (IEEE 802.11)

Intel Wireless Wifi Core

[*] IWLWIFI RF kill support

< > Intel Wireless WiFi 4965AGN

Intel PRO/Wireless 3945ABG/BG Network Connection

[*] Enable Spectrum Measurement in iwl3945 drivers或者你的无线网卡是Intel Wireless WiFi 4965AGN,那么启用iwl4965的驱动.

Linux Kernel Configuration:

Device Drivers --->

[*] Network device support --->

[*] Wireless LAN --->

[*] Wireless LAN (IEEE 802.11)

Intel Wireless Wifi Core

[*] IWLWIFI RF kill support

Intel Wireless WiFi 4965AGN

[*] Enable 802.11n HT features in iwl4965 driver

[*] Enable Spectrum Measurement in iwl4965 driver

[*] Enable Sensitivity Calibration in iwl4965 driver

< > Intel PRO/Wireless 3945ABG/BG Network Connection2.6.26以后的内核中加入了对网卡LED信号灯的支持，但是你需要知道的是当网卡通信的时候LED会不停地闪烁。

Linux Kernel Configuration:

Device Drivers --->

[*] Network device support --->

[*] Wireless LAN --->

[*] Wireless LAN (IEEE 802.11)

Intel PRO/Wireless 3945ABG/BG Network Connection

[*] Enable LEDS features in iwl3945 driver

内核的设置到此为止，下面是软件的了,你需要安装microcode文件

当上面的内容都完成之后你需要为你的无线网卡安装对应的固件来保证网卡正常工作。下面是一个关于micorcode的简单(并不完整)的描述。是从iwl3945-ucode包中自带的文件README.iwlwifi-3945-ucode中提取出来的:

Note: Quote: README.iwlwifi-3945-ucode

The file iwlwifi-3945.ucode provided in this package is required to be present on your system in order for the Intel PRO/Wireless 3945ABG/BG Network Connection Adapter driver for Linux (iwlwifi-3945) to be able to operate on your system.On adapter initialization, and at varying times during the uptime of the adapter, the microcode is loaded into the RAM on the network adapter. The microcode provides the low level MAC features including radio control and high precision timing events (backoff, transmit, etc.) while also providing varying levels of packet filtering which can be used to keep the host from having to handle packets that are not of interest given the current operating mode of the device.安装microcode只需要简单的emerge net-wireless/iwl3945-ucode就可以了

emerge -av net-wireless/iwl3945-ucode或者你的网卡是4956abn,那么emerge net-wireless/iwl4965-ucode

emerge -av net-wireless/iwl4965-ucode

注意: 在2.6.27或者更新的内核中你需要安装iwl4956-ucode的第二个版本(version 228.57.2.21)

强烈建议你详细阅读microcode自带的README文件，它能告诉你很多如何设置这个设备的有用信息。一般来说你可以在/usr/share/doc/iwl3945-ucode-*/或者/usr/share/doc/iwl4956-ucode-*/发现他们。前面的星号是代表你包的版本。

iwlwifi的优点：其实新无线网络堆栈是个必然趋势，而且传输速度更快了。

Reference:gentoo-wiki(iwlwifi)