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ath9k_htc

ath9k_htc provides hardware support for Atheros AR9001 and AR9002 family hardware.

Get the driver

The driver is part of wireless-testing. See this guide to use the wireless-testing tree directly. Or you can use compat-wireless to get the driver.

Chipsets supported

  • AR9271
  • AR7010

Supported Devices

See the ath9k_htc device list.

Mailing list

Configuring your kernel

Enable these options in your kernel config. Most distros will already have it enabled.

CONFIG_ATH_COMMON=m
CONFIG_ATH9K_HW=m
CONFIG_ATH9K_COMMON=m
CONFIG_ATH9K_HTC=m

Firmware

This driver requires firmware. The firmware can be obtained from firmware tree.

Alternately you can download it from here: http://wireless.kernel.org/download/htc_fw/.

This firmware is now open, to contribute check out:

Older firmware map:

AR9271 - ar9271.fw
AR7010 - ar7010.fw or ar7010_1_1.fw

Newer firmware map:

AR9271 - htc_9271.fw
AR7010 - htc_7010.fw

The firmware has to be placed in the correct location, usually /lib/firmware. This could vary among distributions, so check your distro's policies if loading of the firmware fails.

Supported Features

  • Station Mode
  • Monitor Mode
  • AP Mode (NOTE: AP mode works only with up to 7 stations due to a firmware limitation)

  • IBSS Mode
  • Legacy (11g) operation
  • HT support
  • TX/RX 11n AMPDU aggregation
  • HW Encryption
  • LED
  • Suspend/Resume

Disabled Features

ath9k_htc uses the Autosleep feature of the wireless card. Basic PS support has been implemented in the driver, but it is disabled by default.

Modeswitching for AR7010

AR7010 based cards operate by default in USB Mass storage mode and have to be 'switched' to wireless mode on plugging in. If you have an old USB_ModeSwitch package, you can do this to load ath9k_htc automatically.

Add this line to /lib/udev/rules.d/40-usb_modeswitch.rules.

# Atheros Wireless
ATTRS{idVendor}=="0cf3", ATTRS{idProduct}=="20ff", RUN+="usb_modeswitch '%b/%k'"

Add a file "0cf3:20ff" in /etc/usb_modeswitch.d/ and add these lines to it.

########################################################
# Atheros Wireless

DefaultVendor= 0x0CF3
DefaultProduct=0x20FF

TargetVendor=  0x0CF3
TargetProduct= 0x7010

CheckSuccess=10
NoDriverLoading=1

MessageContent="5553424329000000000000000000061b000000020000000000000000000000"

Now, when the device is plugged in, ath9k_htc should load normally. If not, report to ath9k_devel.

Debugging

See here.

Known limitations

The AMPDU size is limited to 22 subframes for UB94/95 and 17 for UB91. Fixing this would require removing lots of cruft and structural changes in the firmware.

AP/P2P Modes

This is experimental !

Patches enabling P2P/AP modes have been merged in wireless-testing, it would be part of the driver from Linux 3.0. Using only one VIF (Virtual Interface) running in AP mode would be a good idea for now, multiple interface support has not been tested extensively. Note: PowerSave is not properly supported yet.

Please do report bugs, crashes, weird behavior and other general tantrums thrown by the driver.

TODO

A list of things that need to be fixed in the firmware.

  • Handle AMPDU subframe limits properly.
  • Handle AMPDU density properly.
  • ERP protection needs to be fixed.
  • RTS/CTS has to be handled properly (for both management and data frames).
  • Processing multicast frames has to be fixed (MultiRateRetry etc.).

  • Short/Long preamble selection has to be fixed.
  • Duration calculation for data, control and management frames.
  • BAR transmission to be moved to the host.
  • Low RSSI issue for UB91/94.
  • TPC for UB94/95 - why is it required ?
  • NOACK handling.
  • Destination mask handling.
  • TX filtering (legacy and HT modes).
  • AMPDU delimiter calculation.
  • AccessClass distribution.

  • Unify TX statistics.
  • MIB interrupt processing (how the fsck does ANI even work now ?)
  • cwMin/cwMax handling.
  • _Three_ different data structures pointing to the same rate control data, really ?
  • Multicast frame completion.
  • World poverty.
  • open firmware for ath9k_htc