Poderia informar o modelo da placa?
Execute em terminal "sudo lshw -C network"
Se atualizar para o Kernel 3.5, poderia resolver o problema ?, visto que seria um Kernel com melhor suporte com placas mais novas.
*-network
description: Wireless interface
product:
RTL8191SEvA Wireless LAN Controller vendor:
Realtek Semiconductor Co., Ltd. physical id: 0
bus info: pci@0000:01:00.0
logical name:
wlan0 version: 10
serial: [retirei por motivo de segurança]
width: 32 bits
clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
configuration: broadcast=yes
driver=rtl8192se driverversion=3.0.0-32-generic firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11bgn
resources: irq:16 ioport:d800(size=256) memory:feafc000-feafffff