[ath9k-devel] Zyxel NWD-170n badly slow

[Andrej Podzimek <andrej@podzimek.org>]

>>> Are you using an ieee80211_regdom module parameter?
>> The ath9k module I use does not accept such a parameter. The same applies to
>> the mac80211 module. Maybe it's not in the vanilla kernel yet? Will try
>> something bleeding-edge ASAP (compat-wireless).
> 
> Was just asking to see if you used it to understand better how your
> cfg80211 is coming up and with what parameters. I do not want you to
> use it but it is available through the cfg80211 module. Just ignore
> this then.

I had cfg80211 compiled into the kernel, not as a module. That's why I could not find out what module is supposed to take that parameter.

I recompiled the kernel to get the cfg80211 module, which is necessary for compat-wireless anyway. Compiled and installed today's compat-wireless afterwards. Added this to modprobe.conf:

	options cfg80211 ieee80211_regdom=CZ

The device initialization now looks like this:

	pcmcia_socket pcmcia_socket0: pccard: CardBus card inserted into slot 0                                           
	pci 0000:02:00.0: reg 10 32bit mmio: [0x000000-0x00ffff]
	cfg80211: Calling CRDA for country: CZ
	ath9k 0000:02:00.0: enabling device (0000 -> 0002)
	ath9k 0000:02:00.0: PCI INT A -> Link[LNKB] -> GSI 5 (level, low) -> IRQ 5
	cfg80211: Regulatory domain changed to country: CZ
	        (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
	        (2400000 KHz - 2483500 KHz @ 40000 KHz), (N/A, 2000 mBm)
	        (5150000 KHz - 5250000 KHz @ 40000 KHz), (N/A, 2301 mBm)
	        (5250000 KHz - 5350000 KHz @ 40000 KHz), (N/A, 2301 mBm)
	        (5470000 KHz - 5725000 KHz @ 40000 KHz), (N/A, 3000 mBm)
	ath: EEPROM regdomain: 0x30
	ath: EEPROM indicates we should expect a direct regpair map
	ath: Country alpha2 being used: AM
	ath: Regpair used: 0x30
	phy0: Selected rate control algorithm 'ath9k_rate_control'
	cfg80211: Calling CRDA for country: AM
	cfg80211: Regulatory domain changed to country: AM
	        (start_freq - end_freq @ bandwidth), (max_antenna_gain, max_eirp)
	        (2402000 KHz - 2482000 KHz @ 40000 KHz), (N/A, 2000 mBm)
	        (5170000 KHz - 5250000 KHz @ 20000 KHz), (N/A, 1800 mBm)
	        (5250000 KHz - 5330000 KHz @ 20000 KHz), (N/A, 1800 mBm)
	Registered led device: ath9k-phy0::radio
	Registered led device: ath9k-phy0::assoc
	Registered led device: ath9k-phy0::tx
	Registered led device: ath9k-phy0::rx
	phy0: Atheros AR5416 MAC/BB Rev:2 AR2122 RF Rev:81: mem=0xf0b80000, irq=5

Now this is how it worked:

	WMM QoS off, 20 MHz channels:	about 24 Mb/s, like 802.11g
	WMM QoS off, 40 MHz channels:	about 10 Mb/s, really bad
	WMM QoS  ON, 20 MHz channels:	about 60 Mb/s
	WMM QoS  ON, 40 MHz channels:	about 56 Mb/s, 60 Mb/s peaks

WMM QoS is just a checkbox in the router's web interface. ;-) I don't know what it exactly does. When I configured this WMM stuff with MadWifi and hostapd, there were at least 30 different settings, not just yes/no. I never thought WMM could influence transfer rates when one client talks to one AP. The checkbox probably does much more than just WMM.

I experimented with iw channel settings, especially HT20, HT40+ and HT40-. However, it either didn't influence the speed in any way, or killed the connection. (The latter is not surprising...) I don't know whether the AP uses HT40+ or HT40-. When wide channels are enabled on the AP, both settings work on the client.

To sum up, the current speed is better than 802.11g, but no better than Atheros' g+.

Maybe I should try the debugfs stuff to get more output data. Would that be helpful, or just loss of time?

There's one more problem I didn't mention. The router was bought here (Czech Republic) and conforms to ETSI, whereas the PCIMCIA card comes from the USA. They both conform to Draft 2.0, but it seems there's some strange compatibility issue.

Andrej