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ath - Atheros IEEE 802.11 wireless network driver
To compile this driver into the kernel, place the following lines in your
kernel configuration file:
Alternatively, to load the driver as a module at boot time, place the
following line in loader.conf(5):
The ath driver provides support for wireless network adapters based on
the Atheros AR5210, AR5211, and AR5212 programming APIs. These APIs are
used by a wide variety of chips; all chips with a PCI and/or CardBus
interface are supported. Chip-specific support is provided by the
Atheros Hardware Access Layer (HAL), that is packaged separately.
Supported features include 802.11 and 802.3 frames, power management,
BSS, IBSS, and host-based access point operation modes. All host/device
interaction is via DMA.
The ath driver encapsulates all IP and ARP traffic as 802.11 frames, how‐
ever it can receive either 802.11 or 802.3 frames. Transmit speed and
operating mode is selectable and depends on the specific chipset.
AR5210-based devices support 802.11a operation with transmit speeds of 6
Mbps, 9 Mbps, 12 Mbps, 18 Mbps, 24 Mbps, 36 Mbps, 48 Mbps, and 54 Mbps.
AR5211-based devices support 802.11a and 802.11b operation with transmit
speeds as above for 802.11a operation and 1Mbps, 2Mbps, 5.5 Mbps and
11Mbps for 802.11b operation. AR5212-based devices support 802.11a,
802.11b, and 802.11g operation with transmit speeds appropriate to each.
Most chips also support an Atheros Turbo Mode (TM) that operates in the
5Ghz frequency range with 2x the transmit speeds. Some chips also sup‐
port Turbo mode in the 2.4Ghz range with 802.11g though this support is
not presently available due to regulatory requirements. (Note that Turbo
modes are, however, only interoperable with other Atheros-based devices.)
The actual transmit speed used is dependent on signal quality and the
“rate control” algorithm employed by the driver. All chips support WEP
encryption. The AR5212 has hardware support for the AES-CCM, TKIP, and
Michael cryptographic operations required for WPA. To enable encryption,
use ifconfig(8) as shown below.
By default, the ath driver configures the card for BSS operation (aka
infrastructure mode). This mode requires the use of an access point
The ath driver also supports the standard IBSS point-to-point mode where
stations can communicate amongst themselves without the aid of an access
The driver may also be configured to operate in hostap mode. In this
mode a host may function as an access point (base station). Access
points are different than operating in IBSS mode. They operate in BSS
mode. They allow for easier roaming and bridge all Ethernet traffic such
that machines connected via an access point appear to be on the local
For more information on configuring this device, see ifconfig(8).
Devices supported by the ath driver come in either Cardbus or mini-PCI
packages. Wireless cards in Cardbus slots may be inserted and ejected on
The ath driver supports all Atheros Cardbus or PCI cards, except those
that are based on the AR5005VL chipset.
A list of cards that are supported can be found at
Join an existing BSS network (ie: connect to an access point):
ifconfig ath0 inet 192.168.0.20 netmask 0xffffff00
Join a specific BSS network with network name “my_net”:
ifconfig ath0 inet 192.168.0.20 netmask 0xffffff00 ssid my_net
Join a specific BSS network with WEP encryption:
ifconfig ath0 inet 192.168.0.20 netmask 0xffffff00 ssid my_net \
wepmode on wepkey 0x8736639624
Join/create an 802.11b IBSS network with network name “my_net”:
ifconfig ath0 inet 192.168.0.22 netmask 0xffffff00 ssid my_net \
mode 11b mediaopt adhoc
Create an 802.11g host-based access point:
ifconfig ath0 inet 192.168.0.10 netmask 0xffffff00 ssid my_ap \
mode 11g mediaopt hostap
Create an 802.11a host-based access point with WEP enabled:
ifconfig ath0 inet 192.168.0.10 netmask 0xffffff00 ssid my_ap \
wepmode on wepkey 0x1234567890 mode 11a mediaopt hostap
Create a host-based wireless bridge to fxp0:
ifconfig ath0 inet up ssid my_ap media DS/11Mbps mediaopt hostap
ifconfig bridge0 create
ifconfig bridge0 addm ath0 addm fxp0 up
This will give you the same functionality as an access point.
ath%d: unable to attach hardware; HAL status %u The Atheros Hardware
Access Layer was unable to configure the hardware as requested. The sta‐
tus code is explained in the HAL include file sys/contrib/dev/ath/ah.h.
ath%d: failed to allocate descriptors: %d The driver was unable to allo‐
cate contiguous memory for the transmit and receive descriptors. This
usually indicates system memory is scarce and/or fragmented.
ath%d: unable to setup a data xmit queue! The request to the HAL to set
up the transmit queue for normal data frames failed. This should not
ath%d: unable to setup a beacon xmit queue! The request to the HAL to
set up the transmit queue for 802.11 beacon frames frames failed. This
should not happen.
ath%d: 802.11 address: %s The MAC address programmed in the EEPROM is
ath%d: hardware error; resetting An unrecoverable error in the hardware
occurred. Errors of this sort include unrecoverable DMA errors. The
driver will reset the hardware and continue.
ath%d: rx FIFO overrun; resetting The receive FIFO in the hardware over‐
flowed before the data could be transferred to the host. This typically
occurs because the hardware ran short of receive descriptors and had no
place to transfer received data. The driver will reset the hardware and
ath%d: unable to reset hardware; hal status %u The Atheros Hardware
Access Layer was unable to reset the hardware as requested. The status
code is explained in the HAL include file sys/contrib/dev/ath/ah.h. This
should not happen.
ath%d: unable to start recv logic The driver was unable to restart frame
reception. This should not happen.
ath%d: device timeout A frame dispatched to the hardware for transmis‐
sion did not complete in time. The driver will reset the hardware and
continue. This should not happen.
ath%d: bogus xmit rate 0x%x An invalid transmit rate was specified for
an outgoing frame. The frame is discarded. This should not happen.
ath%d: ath_chan_set: unable to reset channel %u (%u Mhz) The Atheros
Hardware Access Layer was unable to reset the hardware when switching
channels during scanning. This should not happen.
ath%d: unable to allocate channel table The driver was unable to allo‐
cate memory for the table used to hold the set of available channels.
ath%d: unable to collect channel list from hal A problem occurred while
querying the HAL to find the set of available channels for the device.
This should not happen.
ath%d: failed to enable memory mapping The driver was unable to enable
memory-mapped I/O to the PCI device registers. This should not happen.
ath%d: failed to enable bus mastering The driver was unable to enable
the device as a PCI bus master for doing DMA. This should not happen.
ath%d: cannot map register space The driver was unable to map the device
registers into the host address space. This should not happen.
ath%d: could not map interrupt The driver was unable to allocate an IRQ
for the device interrupt. This should not happen.
ath%d: could not establish interrupt The driver was unable to install
the device interrupt handler. This should not happen.
an(4), arp(4), ath_hal(4), card(4), netintro(4), pcic(4), wi(4), wlan(4),
The ath device driver first appeared in FreeBSD 5.2.
Different regulatory domains have different default channels for adhoc
mode. See ifconfig(8) for information on how to change the channel. See
wicontrol(8) for information on different regulatory domains. Different
regulatory domains may not be able to communicate with each other with
802.11a as different regulatory domains do not necessarily have overlap‐
Revision A1 of the D-LINK DWL-G520 and DWL-G650 are based on an Intersil
PrismGT chip and are not supported by this driver.
There is no software retransmit; only hardware retransmit is used.
The driver does not fully enable power-save operation of the chip; conse‐
quently power use is suboptimal.
The driver honors the regulatory domain programmed into the EEPROM of a
device and does not support overriding this setting. This is done to
insure compliance with local regulatory agencies when operating as an
access point. Unfortunately this also means that devices purchased for
use in one locale may not be usable in another. Changes are planned to
remove this restriction when operating in station mode.
WPA is not supported for 5210 parts.
Atheros’ SuperG functionality is not supported.