While Linux desktop users have long been able to use Wi-Fi cards based on Atheros chip sets, they haven’t been able to do so without using proprietary Atheros code. Now, the Software Freedom Law Center has given the green light to developers working on an open-source substitution for the closed-source code.
The technology in question, OpenHAL, enables users with wireless cards based on technology from Atheros Communications to connect to networks using exclusively free and open-source software.
OpenHAL is low-level interface software for Atheros 802.11 Wi-Fi cards. Without OpenHAL, Linux-based systems need a proprietary HAL (Hardware Abstraction Layer) plus a wrapper driver to use these wireless cards. Thus, OpenHAL is an open-source replacement for Atheros’ proprietary HAL.
OpenHAL was initially based on the ar5k driver, which was used as the basis for a proprietary HAL replacement for the OpenBSD operating system. Support for Atheros cards is especially important for desktop Linux, since Atheros wireless chip sets are commonly used by dozens of Wi-Fi vendors such as 3Com, D-Link and Netgear, as well as many laptop manufacturers, such as Hewlett-Packard, Lenovo and Toshiba.
The developers of OpenHAL faced allegations that their project might include material that infringed Atheros’ HAL copyright. The programmers then asked the SFLC (Software Freedom Law Center) to investigate these rumors.
The SFLC agreed to help on a pro-bono basis, and subsequently conducted a confidential audit that carefully compared OpenHAL to Atheros’ proprietary HAL code.
After performing the audit, SFLC concluded that OpenHAL does not infringe copyrights held by Atheros. As a result, OpenHAL development can now continue safely, so long as the OpenHAL developers continue their work in isolation from Atheros’ proprietary code, it said.
“The OpenHAL developers can now continue development with legal clarity,” said Karen Sandler, an SFLC attorney. “We thank Atheros for granting us confidential access to its proprietary HAL source code for purposes of the review. We join Atheros in encouraging developers to avoid proprietary code in their work, using clean room approaches like the techniques used in the development of OpenHAL.”
Historically, Atheros, while not allowing access to its HAL, has been very supportive of open-source development. It is because of this support that MadWifi has long been able to supply Linux kernel device drivers for Wi-Fi cards that use Atheros-based chip sets for 802.11a, 802.11b and 802.11g compatibility. Eventually, 802.11n cards will also be supported.
“Our ultimate goal is to have full support for Atheros devices included in the Linux kernel,” Luis Rodriguez, a Linux wireless developer, said in a statement. “By providing legal clearance, the Software Freedom Law Center has helped us get one step closer to making this a reality.”
“We believe that this outcome will clear the way for eventual acceptance of a new wireless driver into the Linux kernel,” said John Linville, the Linux kernel maintainer for wireless networking.