[ath9k-devel] AR5416 not fully working

[Benoit PAPILLAULT <benoit.papillault@free.fr>]

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Luis R. Rodriguez a ?crit :
> On Tue, Oct 14, 2008 at 11:29:19PM -0700, Benoit PAPILLAULT wrote:
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> Hey Bonoit!
> 
>> Hi there,
>>
>> I'm currently testing an AR5416 minipci card in a laptop (using 1, 2 or
>> 3 antennas does not make any difference). My configuration is:
>>
>> - - laptop with the minipci card in STA mode
>> - - Linksys WRT350N in AP mode
>> - - another laptop wired to the Linksys AP
>> - - doing iperf between the 2 laptops
>>
>> I'm using wireless-testing tree + the ath9k driver. Here are the problem
>> i'm facing:
>>
>> 1/ Association using wpa_suplicant (WPA2-PSK) is OK
> 
> Yay.
> 
>> 2/ DHCP is always failing (I never got an IP)
> 
> Thanks, this should not fail and it does not fail in my own setup.
> Can you provide the log messages during this?
> 
>> 3/ Using a fixed IP, I'm not able to ping for some time (at least for 80s)
> 
> This needs to be fixed too, can you provide log messages during this?
> I haven't seen this anymore, it used to happen but I no longer see it.
> 
>> 4/ When ping is working, throughout is like 15 Mbits at its maximum.
> 
> You will only get MCS rates but without aggregation. It also depends
> on the noise on the location of where you are testing. More on this below.
> 
>> 5/ During all the test, tcpdump show that the RX side is OK
>>
>> dmesg shows lots of "BA request denied", but apparently that might not
>> be a problem.
> 
> Out of these I take it you mean the second one:
> 
> ht.c:           printk(KERN_DEBUG "BA request denied - session is not "
> ht.c:           printk(KERN_DEBUG "BA request denied - queue unavailable for"
> ht.c:           printk(KERN_DEBUG "BA request denied - HW unavailable for"
> 
> If so I find it strange as aggregation is disabled right now in
> mac80211 -- see ieee80211_ht_agg_queue_add(). But keep in mind ath9k
> ampdu_queues = 1 on ath9k right now and what I've seen so far is ath9k
> sends frames on two tids during a session to an AP some initial data on
> tid 0 and some data frames on tid 6. I think this a bug. Anyway you can
> temporarilly fix this by increasing the number of ampdu_queues ath9k
> declares. This whole ampdu_queues is bogus and just needs to be removed
> to fix aggregation properly in mac80211.
> 
>> Is that a known bug? Did i miss something in my setup? How to debug?
> 
> For now please consider aggregation disabled and broken in mac80211 due
> to two facts:
> 
> 1. Its current design on relying ampdu_queue notion (tid_to_tx_q stuff).
> 2. TX MQ changes require changes in order to deal with overwriting of
>    skb->cb upon having the skb enter the qdisc.
> 
> Our initial work on aggregation addresses the second issue and we tried
> to get it in for 2.6.27 as a temporary solution without having to rm -rf
> ampdu_queue notion yet. This patch didn't make it upstream, however, due
> to the more amount of changes required and some other hacks I saw on the
> way.
> 
> Its now time to simply fix aggregation properly by dealing with these
> two issues. For now please consider aggregation disabled.
> 
>> I will redo the very same test with an AR9160 minipci card as well.
> 
> I suspect you will get similar results. But regardless the issues we
> have to definitely address are your latency on ping/dhcp. Then we can
> move on to throughput concerns but they may very well be related.
> 
>   Luis
> 

Thanks Luis,

I must admit I do not fully understand your reply (I've not read the
802.11n specs .... ). I got the same results with AR9160. The exact
error message is:

BA request denied - queue unavailable for tid 0
BA request denied - queue unavailable for tid 6
BA request denied - queue unavailable for tid 7

However, this time, I got 27 Mbits, ie equivalent to 802.11g.

Are there some patches I can try?
Could you give me more details in order to fix aggregation?

Regards,
Benoit
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