man/man4/ath.4

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.\" $FreeBSD: /repoman/r/ncvs/src/share/man/man4/ath.4,v 1.40 2006/05/12 17:58:11 keramida Exp $
.\" $DragonFly: src/share/man/man4/ath.4,v 1.10 2008/07/26 16:25:40 swildner Exp $
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.Dd July 26, 2008
.Dt ATH 4
.Os
.Sh NAME
.Nm ath
.Nd "Atheros IEEE 802.11 wireless network driver"
.Sh SYNOPSIS
To load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
if_ath_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
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.
.Pp
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.
.Pp
The
.Nm
driver encapsulates all IP and ARP traffic as 802.11 frames, however
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 support 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
.Dq "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
.Xr ifconfig 8
as shown below.
.Pp
By default, the
.Nm
driver configures the card for BSS operation (aka infrastructure
mode).
This mode requires the use of an access point (base station).
.Pp
The
.Nm
driver also supports the standard IBSS point-to-point mode
where stations can communicate amongst themselves without the
aid of an access point.
.Pp
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
Ethernet segment.
.Pp
For more information on configuring this device, see
.Xr ifconfig 8 .
.Pp
Devices supported by the
.Nm
driver come in either Cardbus or mini-PCI packages.
Wireless cards in Cardbus slots may be inserted and ejected on the fly.
.Sh HARDWARE
The
.Nm
driver supports all Atheros Cardbus or PCI cards,
except those that are based on the AR5005VL chipset.
.Pp
A list of cards that are supported can be found at
.Pp
.Pa http://customerproducts.atheros.com/customerproducts .
.Sh EXAMPLES
Refer to the
.Sx EXAMPLES
section of
.Xr wlan 4 .
.Sh DIAGNOSTICS
.Bl -diag
.It "ath%d: unable to attach hardware; HAL status %u"
The Atheros Hardware Access Layer was unable to configure the hardware
as requested.
The status code is explained in the HAL include file
.Pa sys/contrib/dev/ath/ah.h .
.It "ath%d: failed to allocate descriptors: %d"
The driver was unable to allocate contiguous memory for the transmit
and receive descriptors.
This usually indicates system memory is scarce and/or fragmented.
.It "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 happen.
.It "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.
.It "ath%d: 802.11 address: %s"
The MAC address programmed in the EEPROM is displayed.
.It "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.
.It "ath%d: rx FIFO overrun; resetting"
The receive FIFO in the hardware overflowed 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 continue.
.It "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
.Pa sys/contrib/dev/ath/ah.h .
This should not happen.
.It "ath%d: unable to start recv logic"
The driver was unable to restart frame reception.
This should not happen.
.It "ath%d: device timeout"
A frame dispatched to the hardware for transmission did not complete in time.
The driver will reset the hardware and continue.
This should not happen.
.It "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.
.It "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.
.It "ath%d: unable to allocate channel table"
The driver was unable to allocate memory for the table used to hold
the set of available channels.
.It "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.
.It "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.
.It "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.
.It "ath%d: cannot map register space"
The driver was unable to map the device registers into the host address space.
This should not happen.
.It "ath%d: could not map interrupt"
The driver was unable to allocate an IRQ for the device interrupt.
This should not happen.
.It "ath%d: could not establish interrupt"
The driver was unable to install the device interrupt handler.
This should not happen.
.El
.Sh SEE ALSO
.Xr an 4 ,
.Xr arp 4 ,
.Xr ath_hal 4 ,
.Xr ifmedia 4 ,
.Xr netintro 4 ,
.Xr wi 4 ,
.Xr wlan 4 ,
.Xr hostapd 8 ,
.Xr ifconfig 8 ,
.Xr wpa_supplicant 8
.Sh HISTORY
The
.Nm
device driver first appeared in
.Fx 5.2
and was imported into
.Dx 1.5 .
.Sh CAVEATS
Different regulatory domains have different default channels for adhoc
mode.
See
.Xr ifconfig 8
for information on how to change the channel.
Different regulatory domains may not be able to communicate with each
other with 802.11a as different regulatory domains do not necessarily
have overlapping channels.
.Pp
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.
.Pp
Revision v3 of the Netgear WG311 is based on a Marvell Libertas
88W8335 and is not supported by this driver.
.Sh BUGS
There is no software retransmit; only hardware retransmit is used.
.Pp
The driver does not fully enable power-save operation of the chip;
consequently power use is suboptimal.
.Pp
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.
.Pp
WPA is not supported for 5210 parts.
.Pp
Atheros' SuperG functionality is not supported.