Slow performance HostAPD with B43 and NL80211

Ino Dekker ino.dekker at gmail.com
Fri Nov 21 14:51:44 EST 2008


I'm trying to convert an old P3 into a wireless router + AP with 2 ethernet
ports and a wlan port.
I'm using a Asus WL-138G v2 PCI Card with 4318 chipset.
I'm running Ubuntu 8.10 with 2.6.27-7 kernel and I've build the latest b43
and ssb drivers/modules from compat-wireless-2.6, as described on
http://www.linuxwireless.org, which includes the latest firmware for the
b43. Also, as suggested, I've build and installed the latest version of
HostAPD from the git repository.

Apart from initial setup problems, I have three problems remaining from
getting a perfect setup:
1) On system start-up, the b43 module will not load, because ssb is already
loaded and is not the right version ('b43: disagrees about version of symbol
ssb_device_is_enabled'). After start-up I unload module ssb and then load
b43 and it will work fine. I'm not sure how to solve this problem that i
don't need to unload and load after start-up (and also having to restart
networking, hostapd and dhcp3-server).

2) My Windows XP laptop (with intel 802.11g wireless and using standard XP
toolset) is having difficulties connecting with the wireless AP when I use
WPA2 Personal security. It will connect, but often only after disabling and
enabling the radio on the laptop. On the same laptop in my Ubuntu
environment it works perfectly, as for Windows XP with open system (no
WPA2). Another XP laptop with intel 802.11g wireless with Intel toolset is
having no difficulties with the WPA2 Personal security enabled. So far I'm
unsure what to do to solve this problem. However, it might be related to my
3rd problem.

3) The third and last problem is the most problematic one, as it will
actually block me from using this setup. When the connection is made, and
the client is reporting an excellent link, the maximum transfer speed is
about 100 kbytes/s (both up and down). With WPA2 security the transfer rate
is a little lower compared to open system. While transferring, it is nearly
impossible to setup another connection or to browse some where else.
However, the system load on the P3 is still very low. I've been testing
numerous things:
- Set different channels.
- Limiting the rates to 5.5M (in hostapd)
- Disabling security.
- Not using bridge of wlan0 and eth0 (eth1 is the WAN port)
- Different b43 firmware (not working) and original b43/ssb module (not
possible to run in master mode)
None of the above gave me any clue to where the problem lies. I've kept most
settings at their default settings and hostapd logging doesn't show anything
unusual, except for the occasional 'b43-phy0 ERROR: PHY transmission error',
but these are not that often to cause this huge drop in performance.
To test the cards' capabilities, i used the b43 in normal mode connecting to
my current ADSL router: about 950 kbytes/s, so it is possible to go faster.

Any help to debug this problem is appreciated.
Below I've listed some useful information, if more is needed, I'll try to
retrieve it.

Thanks!

Some useful information:
ino at router:~$ uname -a
Linux router 2.6.27-7-server #1 SMP Tue Nov 4 20:18:35 UTC 2008 i686
GNU/Linux

Excerpt from dmesg:
[   39.844244] b43-pci-bridge 0000:02:0a.0: PCI INT A disabled
[   39.926191] b43-pci-bridge 0000:02:0a.0: PCI INT A -> GSI 21 (level, low)
-> IRQ 21
[   40.040137] ssb: Sonics Silicon Backplane found on PCI device
0000:02:0a.0
[   40.082437] b43-phy0: Broadcom 4318 WLAN found
[   40.241470] phy0: Selected rate control algorithm 'pid'
[   40.405151] Broadcom 43xx driver loaded [ Features: PMLR, Firmware-ID:
FW13 ]
[   50.832520] input: b43-phy0 as /devices/virtual/input/input5
[   51.030098] firmware: requesting b43/ucode5.fw
[   51.105630] firmware: requesting b43/pcm5.fw
[   51.119585] firmware: requesting b43/b0g0initvals5.fw
[   51.132490] firmware: requesting b43/b0g0bsinitvals5.fw
[   51.260089] b43-phy0: Loading firmware version 410.2160 (2007-05-26
15:32:10)
[   51.330476] Registered led device: b43-phy0::tx
[   51.330539] Registered led device: b43-phy0::rx
[   51.330586] Registered led device: b43-phy0::assoc
[   51.330635] Registered led device: b43-phy0::radio
[   51.370133] b43-phy0: Radio turned on by software
[   52.316951] input: b43-phy0 as /devices/virtual/input/input6
[   52.630036] b43-phy0: Loading firmware version 410.2160 (2007-05-26
15:32:10)
[   52.700474] Registered led device: b43-phy0::tx
[   52.700536] Registered led device: b43-phy0::rx
[   52.700581] Registered led device: b43-phy0::assoc
[   52.700631] Registered led device: b43-phy0::radio

My hostapd.conf (partly):
interface=wlan0
driver=nl80211
ssid=DekkerHome
country_code=EU
hw_mode=g
channel=1
beacon_int=100
dtim_period=2
max_num_sta=255
rts_threshold=2347
fragm_threshold=2346
macaddr_acl=0
auth_algs=3
ignore_broadcast_ssid=0
wme_enabled=1
wme_ac_bk_cwmin=4
wme_ac_bk_cwmax=10
wme_ac_bk_aifs=7
wme_ac_bk_txop_limit=0
wme_ac_bk_acm=0
wme_ac_be_aifs=3
wme_ac_be_cwmin=4
wme_ac_be_cwmax=10
wme_ac_be_txop_limit=0
wme_ac_be_acm=0
wme_ac_vi_aifs=2
wme_ac_vi_cwmin=3
wme_ac_vi_cwmax=4
wme_ac_vi_txop_limit=94
wme_ac_vi_acm=0
wme_ac_vo_aifs=2
wme_ac_vo_cwmin=2
wme_ac_vo_cwmax=3
wme_ac_vo_txop_limit=47
wme_ac_vo_acm=0
own_ip_addr=192.168.0.1
wpa=0
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