> Hi all.
>
> We, the MadWifi team, announce our decision to move away from the
> binary-only HAL and change the focus of our future development towards
> ath5k [1], a completely free (as in freedom) driver which will eventually
> become an integral part of the Linux kernel. We encourage all interested
> developers to join us and contribute to our efforts.
>
> For those who are not familiar with the concept, the proprietary "Hardware
> Abstraction Layer" (HAL) [2] was designed as compromise to allow at least
> one Free and Open Source Software (FOSS) wireless driver component. Unlike
> many other wireless devices Atheros chipsets can use a wide range of
> frequencies and the host software can control many aspects of the radio.
> Regulatory agencies all over the world have laws which restrict the use of
> the wireless spectrum to certain frequency bands under specific
> transmission power levels. These laws drive wireless manufacturers to come
> up with solutions to enforce compliance with the wide array of regulatory
> agencies. The binary HAL is a wrapper around all chipset registers, and
> all direct hardware access is routed through it. This approach ensures
> that non-compliant settings are not applied to the radio, while allowing
> the open source part of the driver to interact with the chipset in a
> permissive manner.
>
> We understand Atheros' reasons for introducing the HAL and distributing it
> in binary form only, and we supported it. But this decision forced us to
> deal with a black box that we could neither fix nor fully understand - a
> major issue for a free software project. This prevented MadWifi from
> appearing in many Linux distributions. Because of the proprietary HAL and
> since the MadWifi driver also did not make use of the new mac80211 layer
> in Linux it has been impossible for it to become part of the Linux kernel.
> It's also been clear to us that the "security through obscurity" approach
> won't work to protect the hardware against unlawful use. Regardless, we
> kept working on MadWifi as no acceptable alternative existed.
>
> This situation has changed.
>
> A driver for Atheros wireless cards is available in OpenBSD that talks
> directly to the hardware, based on reverse engineering efforts done by
> Reyk Floeter. Relevant parts of the driver have been ported to Linux by
> Nick Kossifidis to start OpenHAL [3], a free (as in freedom) replacement
> of the proprietary HAL. Claims that the OpenBSD driver (and thus also
> OpenHAL) contains stolen code slowed down the OpenHAL efforts but finally
> could be voided. The Software Freedom Law Center (SFLC) [4], with the help
> of Atheros, performed a thorough code review and concluded "that OpenHAL
> does not infringe copyrights held by Atheros" [5]. In other words, the way
> is clear now for the inclusion of an OpenHAL-based driver into the Linux
> kernel.
>
> Another important development is the work on a "central regulatory domain
> agent". It aims to ensure compliance with the regulatory constraints and
> rules based on the current location of the user. The agent and its
> integration with the kernel will allow wireless LAN drivers to enforce
> local regulations without requiring non-free software for that task. This
> work will soon be published for merging with the upstream kernel.
>
> We now see a road to move away from the binary-only HAL; it's no
> comfortable road, however, and thus requires full concentration of our
> resources to finally reach the ultimate goal of getting a free driver for
> Atheros devices into the Linux kernel. This free driver is called ath5k,
> and the work on it has already been started. We are also in contact with
> Atheros to encourage them to support these efforts.
>
> To underline our decision and commitment to ath5k we now declare MadWifi
> "legacy.". In the long run ath5k will replace the MadWifi driver. For the
> time being MadWifi will still be supported, bugs will get fixed and HAL
> updates will be applied where possible. But it becomes unlikely that we'll
> see new features or go through major changes on that codebase. The only
> exception to this is the work spent on improved support for Dynamic
> Frequency Selection (DFS) [6], which is used for avoiding interference
> with radars.
>
> Users who need stable and solid WLAN support for their Linux computers
> should stick with MadWifi for now. Interested parties are welcome to try
> ath5k and any constructive feedback is highly appreciated.
>
> We encourage developers to contribute [7] to the free driver efforts -
> it's still a long way before we reach the goal of a truly free Atheros
> driver for Linux, and every helping hand is welcome.
>
> If you have any questions, feel free to ask. Thanks for listening.
>
> -- The MadWifi Team
>
> Links:
> [1]
http://madwifi.org/wiki/About/ath5k
> [2]
http://madwifi.org/wiki/About/HAL
> [3]
http://madwifi.org/wiki/About/OpenHAL
> [4]
http://softwarefreedom.org/
> [5]
http://www.softwarefreedom.org/news/2007/jul/31/openhal/
> [6]
http://en.wikipedia.org/wiki/IEEE_802.11h#DFS_Dynamic_Frequency_Selection
> [7]
http://linuxwireless.org/en/users/Drivers/ath5k#Hackingath5k
>
>
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