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Message-ID: <4D8F506B.8070808@openwrt.org>
Date: Sun, 27 Mar 2011 16:57:47 +0200
From: Felix Fietkau <nbd@openwrt.org>
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To: =?ISO-8859-1?Q?Klaus_M=FCller?= <kmueller@justmail.de>
CC: linux-wireless@vger.kernel.org
Subject: Re: broken ath9k-driver - problems with creating new TCP-connections.
 Bad performance
References: <4D8F28C1.4060402@justmail.de> <4D8F2F3E.9030802@openwrt.org> <4D8F4B9F.9010809@justmail.de>
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On 2011-03-27 4:37 PM, Klaus M?ller wrote:
> Felix Fietkau wrote:
>>  On 2011-03-27 2:08 PM, Klaus M?ller wrote:
>>>  Hello,
>>>
>>>  I'm running kernel 2.6.38.1 (from the OpenSuSE buildservice on OpenSuSE
>>>  11.4) and compat-wireless-2011-03-26 (the performance / functionality of
>>>  the driver delivered with 2.6.38.1 is unusable).
>>>  [...]
>>>  iwconfig wlan0
>>>
>>>  wlan0     IEEE 802.11bgn  ESSID:"ssid"
>>>             Mode:Managed  Frequency:2.412 GHz  Access Point:
>>>  00:25:33:22:11:00
>>>             Bit Rate=150 Mb/s   Tx-Power=17 dBm
>>>             Retry  long limit:7   RTS thr:off   Fragment thr:off
>>>             Encryption key:off
>>>             Power Management:on
>>>             Link Quality=14/70  Signal level=-63 dBm
>>>             Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
>>>             Tx excessive retries:4  Invalid misc:1423   Missed beacon:0
>>>
>>>
>>>  I run iwconfig 3 times in 7 seconds. The link quality alternated between
>>>  47 and 14.
>>>
>>  Have you tried switching your AP to HT20 instead of HT40 to see if that
>>  improves stability?
>
> If the AP is set to HT20, this driver doesn't use IEEE 802.11n any more,
> or, to say it more specific: the selected bit rate is max. 64 Mb/s and
> the performance is even worse.
>
> I'm wondering at all, why the ath9k driver doesn't switch to 300 Mb/s:
> the rt3572sta-driver doesn't have any problem with both settings.
AR9285 is a single stream chipset, so it only has one antenna and can't 
do any MIMO.

- Felix