poor performance with W2CBW003 (Marvell 8686)

[Andreas Kemnade]

Hi,

on the GTA04 (www.gta04.org) 
which has a W2CBW003 chip for wifi connected to a DM3730CBP CPU. data
rates are quite low using the libertas driver from kernel 3.2-3.4 
(https://github.com/neilbrown/gta04/branches)
even near an accesspoint. That seems not depend on the encryption
settings. Rates are around 100KByte/s. iwconfig shows 5.5Mb/s if it is
not connected to an accesspoint with specially configured rates (but
still the throughput is low).

In contrary data rates are high (>1MByte/s) with a kernel based on
the 2.6.32  BeagleBoard XM hw-validation kernel
https://github.com/goldelico/gta04-kernel
That behaviour was reported by several people.

I tried also the libertas-tf driver with kernel 3.2 using the
instructions here:
http://corysohrakoff.wordpress.com/2011/09/13/enabling-wifi-ap-mode-on-a-gumstix-overo/
That was also slow.

Any hints?

Greetings
Andreas Kemnade