Rt2860sta

Summary
This article describes how to integrate Ralink staging driver (opensource rt2x00 driver is not ready to use at current moment) into Gentoo baselayout (automated start/restart/stop).

Initially the motivation was to get ad-hoc mode running with Planet WNL-9320 card.

Ralink driver 2010_01_29_RT2860_Linux_STA_v2.3.0.0 which released to wide public doesn't support AP(master) mode.

The environment consists of workstation PC and two notebooks (Lenovo T60 and Dell D430). Both notebooks contain Intel 3945ABG cards.

It covers:
 * Getting and building the driver sources.
 * Patching of rc-scripts.
 * Renaming of network interface.
 * Configuring network interface.

Getting driver sources
Ralink website Linux page

Driver patches

 * The patch to support AP (master) mode required.
 * The patch for proper resuming required. After PC resumed, iwpriv ra0 connStatus reports disconnected. While beacon present. Restarting of client wireless interface doesn't help.
 * The patch to avoid setting essid twice in ad-hoc mode.

Kernel Configuration
Latest git kernels includes rt2860sta sources. So you may skip building the standalone module in this case.

rc-script patches
There is issue with starting raX interface using procedure defined in iwconfig.sh. For some reasons this procedure must be complaint with devicescape stack. This implies that interface must be down before doing certain operations. Ralink driver doesn't accept this behavior - interface must be up before setting any parameters. Thus the line with setting iface down has to be adopted or removed for raX:

net if configuration
Here is the configuration of network interface on pseudo-AP side. This file shows how to set ad-hoc mode using iwconfig interface. For more information please check /etc/init.d/wireless.example

net if renaming
The udev may generate the rule template during emerge process. The template must be modified in order to be compatible with rt2860sta driver.


 * DRIVERS key must be removed.
 * MAC address must be changed to zero. This is because the interface should be in down state before renaming. Otherwise the renaming will not work. So make sure that files do not exists.

Performance comparison
iperf tool used to estimate performance. Unfortunately Atheros AR5008 driver on D430 notebook doesn't support 802.11n in ad-hoc mode. Thus data measured on Windows XP added here for reference.

For 802.11g sustained through-output about 20 MBits/sec both for Windows and Linux.

For 802.11n on the same channel 2, the value about 60 MBits/sec for Windows only. Since AR5008 Windows driver requires infrastructure mode for 802.11n;

Capabilities/Compatibility/Limitations
* Works stable with Intel 3945ABG in 802.11g * Works stable with Atheros AR5008 in 802.11g