Rfloading449

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This is the web site for the Third Edition of Linux Device Drivers,by Jonathan Corbet, Alessandro Rubini, and Greg Kroah-Hartman. For themoment, only the finished PDF files are available; we do intend to make anHTML version and the DocBook source available as well.

• Oracle Linux is free to download, use and distribute and is provided in a variety of installation and deployment methods. The developer preview releases are for development and test purposes only and are not covered by Oracle Linux support. Oracle does not recommended using preview releases in.
• Installation and Use Rights.For installation and use of the Software on any non-Windows platform, including but not limited to macOS and Linux, you may install and use one copy of the Software on any device running such non-Windows platform.

This book is available under the terms of the Creative CommonsAttribution-ShareAlike 2.0 license. That means that you are free todownload and redistribute it. The development of the book wasmade possible, however, by those who purchase a copy from O'Reilly orelsewhere.

LDD3 is current as of the 2.6.10 kernel. See the LWN 2.6 API changes page forinformation on subsequent changes.

LDD3 chapter files

Title page	PDF
Copyright and credits	PDF
Table of Contents	PDF
Preface	PDF
Chapter 1: An Introduction to Device Drivers	PDF
Chapter 2: Building and Running Modules	PDF
Chapter 3: Char Drivers	PDF
Chapter 4: Debugging Techniques	PDF
Chapter 5: Concurrency and Race Conditions	PDF
Chapter 6: Advanced Char Driver Operations	PDF
Chapter 7: Time, Delays, and Deferred Work	PDF
Chapter 8: Allocating Memory	PDF
Chapter 9: Communicating with Hardware	PDF
Chapter 10: Interrupt Handling	PDF
Chapter 11: Data Types in the Kernel	PDF
Chapter 12: PCI Drivers	PDF
Chapter 13: USB Drivers	PDF
Chapter 14: The Linux Device Model	PDF
Chapter 15: Memory Mapping and DMA	PDF
Chapter 16: Block Drivers	PDF
Chapter 17: Network Drivers	PDF
Chapter 18: TTY Drivers	PDF
Index	PDF

Downloads

Also available:

• A tarball of the LDD3 PDF files (11MB).

Download Linux Developer Community Others Drivers

b43 and b43legacy are drivers for the 802.11b/g/n family of wireless chips that Broadcom produces.

Note: Broadcom USB devices are handled by the brcmfmac driver.

• b43legacy: supports BCM4306 Rev 2 and cards that have only 802.11b capability

• b43: supports all other models

Kernel automatically loads correct driver for the present hardware (it checks for revision of the 802.11 core).

Please read this whole document and the FAQ before asking questions to the developers.

Contents

1. Features
2. Device firmware installation

• The b43/b43legacy drivers require proprietary firmware to be loaded onto the wireless chip before it can operate, see below.

• If you have a Broadcom USB device, it's most likely a FullMAC device. See rndis_wlan for 14e4:4320 and brcmfmac for others. The b43/b43legacy driver is not meant to support such a device.

• It is possible to use only one driver at a moment, they are conflicting each other. See Switching between drivers for howto on choosing driver.

• LP-PHY devices: DMA errors on some machines with kernel 2.6. Problem was fixed in 3.0. Using PIO (module param) can be used as workaround for 2.6.

• BCM4318 chipset: AP mode does not work because of packet loss in high transmission rates. Hard to debug & fix.

• BCM4321: some cards do not work in DMA mode with kernel 3.1 and older. Problem was fixed in 3.2. A workaround for older kernel is to use PIO mode (b43.pio=1 module param).

• G-PHY devices: not working with kernels 3.15 and 3.16-rc1 (a regression). This was fixed in 3.15.5 (6f3f164) and 3.16-rc3 (2fc68eb).

To find out whether a PCI device is supported by the b43 or b43legacy drivers, issue this lspci command:

The command will output a string similar to this example:

Ignore everything, except the last part inside of the [ ]. Find that phrase in the below table to determine support.

PCI-ID	Supported?	Chip ID	Modes	PHY version	Alternative
14e4:0576	not tested	BCM43224	a/b/g/n	?	wl/brcm80211
14e4:4301	yes (b43legacy)	BCM4301	b	B
14e4:4306	yes (b43legacy)	BCM4306/2	b/g	G
14e4:4307	yes	BCM4306/3	b/g	G
14e4:4311	yes	BCM4311	b/g	G	wl
14e4:4312	yes	BCM4311	a/b/g	G (r8)	wl
14e4:4313	not tested	BCM4311	a	?	wl
	no	BCM4313	b/g/n	LCN (r1)	wl/brcm80211
14e4:4315	yes	BCM4312	b/g	LP (r1)	wl
14e4:4318	yes	BCM4318	b/g	G (r7)
14e4:4319	yes	BCM4318	a/b/g	G
14e4:4320	yes (b43legacy)	BCM4306/2	b/g	G (r1)
	yes	BCM4306/3	?	G (r2)
14e4:4321	partially	BCM4321	?	N (r2)
14e4:4322	not tested	BCM4322	b/g/n	N (r4)
14e4:4324	yes (b43legacy)	BCM4306	a/b/g	G (r1)
	yes	BCM4306/3	a/b/g	G (r5)
14e4:4325	yes (b43legacy)	BCM4306/2	b/g	G (r1)
14e4:4328	partially	BCM4321	a/b/g/n	N (r2)	wl
14e4:4329	partially	BCM4321	b/g/n	N (r1)	wl
14e4:432a	not tested	BCM4321	a/n	N	wl
14e4:432b	partially	BCM4322	a/b/g/n	N (r4)	wl
14e4:432c	yes	BCM4322	b/g/n	N	wl
14e4:432d	not tested	BCM4322	a/n	N	wl
14e4:4331	yes (3.2-rc3+)	BCM4331	a/b/g/n	HT (r1)	wl
14e4:4350	yes (3.8+)	BCM43222	a/b/g/n	N (r6)
14e4:4353	yes (3.1+)	BCM43224	a/b/g/n	N (r6)	wl/brcm80211
14e4:4357	yes (3.1+)	BCM43225	b/g/n	N (r6)	wl/brcm80211
14e4:4358	yes (3.17+)	BCM43227	b/g/n	N (r16)	wl
14e4:4359	yes (3.17+)	BCM43228	a/b/g/n	N (r16)	wl
14e4:4360	no	BCM4360	?	AC (r1)
14e4:4365	no	BCM43142	b/g/n	LCN40 (r3)	wl
14e4:43a0	no	BCM4360	a/b/g/n/ac	AC?	wl
	no	BCM4352	a/b/g/n/ac	?	wl
14e4:43a9	yes (3.17+)	BCM43217	b/g/n	N (r17)
14e4:43aa	yes (3.17+)	BCM43131	b/g/n	N (r17)
14e4:43b1	no	BCM4352	a/b/g/n/ac	AC?
14e4:4727	no	BCM4313	b/g/n	LCN (r1)	wl/brcm80211
14e4:a8d6	not tested	BCM43222	?	N (6)
14e4:a8d8	yes (3.6+)	BCM43224	a/b/g/n	N (r6)
	yes (3.6+)	BCM43225	?	N (r6)
14e4:a8db	not tested	BCM43217	b/g/n	N (r17)
14e4:a99d	not tested	BCM43421?	?	?	wl

Note that the PCI-ID is not in direct correlation with the Chip ID. Often the PCI-ID equals the Chip ID, but that is not always the case and it is a constant source of confusion.

For a list of available devices, please see the device list.

Please note that we do not support wl or brcm80211 drivers.

• IRC: server is irc.freenode.net, channel is #bcm-users (English please)

• Mailing list: http://lists.infradead.org/mailman/listinfo/b43-dev

Working

• Station mode
• Mesh networking mode (b43 only)
• Access Point mode
• Ad-Hoc (IBSS) mode (b43 only)
• Monitor and Promisc mode.
• 'Monitor while operating' and multiple monitor interfaces.
• In-Hardware traffic de/encryption (relieves your CPU).
• LEDs to signal card state and traffic.
• In-Hardware MAC address filter (b43 only; impossible on b43legacy hardware)
• Packet injection (with radiotap; no FCS injection currently though hardware supports it - a radiotap flag is being discussed for this)
• Bluetooth coexistence protection, if the bluetooth card is physically connected to the wireless chip. (Does not protect against external BT dongles)
• Probably something we forgot to add here.

Not working yet

• Interference mitigation.
• 802.11n: HT
• 802.11n: aggregation
• 802.11n: 40MHz channels
• 5 GHz band

The Broadcom wireless chip needs proprietary software (called 'firmware') that runs on the wireless chip itself to work properly. This firmware is copyrighted by Broadcom and must be extracted from Broadcom's proprietary drivers. To get such firmware on your system, you must download the driver from a legal distribution point, extract it, and install it. This is accomplished different ways by different Linux distributions, so please read the section for yours for the best results. You will need an alternate working internet connection (by Ethernet cable, for example) since the firmware cannot be included with the distro itself.

Post details for missing distributions at b43-dev@lists.infradead.org . Note: the firmware from the binary drivers is copyrighted by Broadcom Corporation and cannot be redistributed.

Fedora

With Fedora 10 and above, you should install wget and the b43-fwcutter tool (which will extract firmware from the Windows driver):

Next use the instructions here, skipping b43-fwcutter installation part.

openSUSE

openSUSE 11.3 and above includes a utility that will automatically download the firmware and install it into its proper location. With working Internet access, run the following commands:

Ubuntu/Debian

In recent versions of Ubuntu and Debian, installing the firmware-b43-installer package will handle everything for you:

You will be asked to automatically fetch and install the firmware into the right location. Again, you will need an internet connection.

Ubuntu Community Documentation

Ubuntu also has a page detailing the process of installing Broadcom wireless drivers on their community documentation. If you have internet access on the device that you want to install the b43 driver onto, follow this link: https://help.ubuntu.com/community/WifiDocs/Driver/bcm43xx#b43%20-%20Internet%20access . If you do not have internet access on the device that has a b43 supported broadcom wireless chipset and would like to use b43, follow this link instead: https://help.ubuntu.com/community/WifiDocs/Driver/bcm43xx#b43%20-%20No%20Internet%20access.

Note that you can only follow one of the two guides, not both.

Gentoo

Gentoo systems supply a pre-compiled binary for b43-fwcutter. You need to:

and then follow the instructions below to download the Broadcom driver. The line that invokes b43-fwcutter will need to be changed to execute the program emerged above.

Mandriva

See the instructions at http://wiki.mandriva.com/en/Installing_wireless_network_cards_using_the_b43_driver

Other distributions not mentioned above

Note: You need to have a compiler and headers for libc installed, since you will have to build fwcutter from source

Install b43-fwcutter

Use version 018 of b43-fwcutter.
Download, extract the b43-fwcutter tarball and build it:

If verification of the GPG signature fails due to an unknown key, you need to import the following key:

If you are using the b43 driver from 3.2 kernel or newer:

After installing b43-fwcutter, download version 5.100.138 of Broadcom's proprietary driver and extract the firmware from it:

If you are using the b43 driver from older kernel:

After installing b43-fwcutter, download version 5.10.56.27.3 of Broadcom's proprietary driver and extract the firmware from it:

Note that you must adjust the FIRMWARE_INSTALL_DIR path to your distribution. The standard place where firmware is installed to is /lib/firmware. However some distributions put firmware in a different place.

If you are using the b43legacy driver:

After installing b43-fwcutter, download version 3.130.20.0 of Broadcom's proprietary driver and extract the firmware from it:

Note that you must adjust the FIRMWARE_INSTALL_DIR path to your distribution. The standard place where firmware is installed to is /lib/firmware. However some distributions put firmware in a different place.

Many different drivers are or have been in use to support Broadcom chipsets, so the terminology is very confusing. The sections below aim to help you understand what is what.

Basic info	b43	STA (wl)	brcmsmac
Open source	yes	no	yes
In kernel	yes	no	yes
Supported buses	b43	wl	brcmsmac
ssb	yes	yes	no
bcma	yes	yes	yes
usb	no	no	no
Supported PHYs	b43	wl	brcmsmac
G	yes	yes	no
N	yes	yes	yes
LP	yes	yes	no
HT	yes	no	no
LCN	no	yes	yes
Supported modes	b43	wl	brcmsmac
Managed	yes	yes	yes
Ad-Hoc	yes	yes	unknown
Monitor	yes	yes	no
AP	yes	no	no

There is also b43legacy driver for some old cards: B-PHY and early G-PHY ones. These cards can't run new firmware, so hardware encryption is unsupported on them.

Please note b43 developers don't offer support for the STA (wl) driver due to the fact that it's mainly proprietary. Contact Broadcom's support.

If you have few drivers installed, system may auto-load different driver than the one you wanted to use. Manual (un)loading drivers can be done with modprobe tool.

To unload all known drivers (you can pick only one command, if you know which driver is in use) perform:

To load specific driver use one of the following commands:

It is possible to prevent system from auto-loading some drivers by blacklisting them. This can be done with the following command:

If you plan to use wl, you should blacklist b43 and brcmsmac as well as bcma. Unfortunately wl does not use bcma bus driver, so this additional step is required.

If you encounter a bug, you should send a message to the b43/b43legacy mailing list at b43-dev@lists.infradead.org containing ALL of the following:

• A description of the problem at hand
• When it happens
• How to reproduce
• wlan configuration and authentication/encryption type
• The output of the following commands:

In addition the following may be of interest to developers:

• If you have built the kernel from git, tell which tree, the output of 'git describe'
• If the driver worked with earlier kernels, but has since stopped working, a bisection is of great value.

Download Linux Developer Community Others Driverpack

See developers page for some advanced info, tools.

Many people have donated money, hardware or other services to make this driver possible. Thanks! Please see the donations page for details.

• Broadcom Wireless-LAN section

• Proprietary Broadcom wl driver