[ath9k-devel] AR9280 with only one antenna?

[Jussi Haakana <jussi.haakana@7signal.com>]

On 9.3.2011 18:04, Adrian Chadd wrote:
> I didn't think the radiotap knew about MIMO. :)
>
> It's possible you're being told about the "old" antenna selection/information stuff.

Hmm. I think that receiving antenna is set in ath9k_rx_skb_preprocess() 
(recv.c:984) to ieee80211_rx_status from which it is then copied
to radiotap by mac80211?

- Jussi
>
>
> Adrian
>
> On 9 March 2011 23:14, Mohammed Shafi<shafi.wireless at gmail.com<mailto:shafi.wireless@gmail.com>>  wrote:
> On Wed, Mar 9, 2011 at 6:34 PM, Jussi Haakana<jussi.haakana at 7signal.com<mailto:jussi.haakana@7signal.com>>  wrote:
>> On 9.3.2011 14:29, Mohammed Shafi wrote:
>>>
>>> On Wed, Mar 9, 2011 at 5:21 PM, Jussi Haakana<jussi.haakana at 7signal.com<mailto:jussi.haakana@7signal.com>>
>>>   wrote:
>>>>
>>>> On 9.3.2011 13:39, Mohammed Shafi wrote:
>>>>>
>>>>> On Wed, Mar 9, 2011 at 4:32 PM, Adrian Chadd<adrian at freebsd.org<mailto:adrian@freebsd.org>>
>>>>>   wrote:
>>>>>>
>>>>>>
>>>>>> I've found a couple places that hard-code setting up both chains (eg
>>>>>> open-loop TX power control, which initialises it for both chains in the
>>>>>> same
>>>>>> location!) but that shouldn't matter.
>>>>>>
>>>>>> There's a function which sets the TX chainmask based on the
>>>>>> sleep/btcoex
>>>>>> mode, maybe you could try setting it to 0x1 there and see what happens.
>>>>>
>>>>>    also hardcoding to 0x1 in the function of  int
>>>>> ath9k_hw_fill_cap_info(struct ath_hw *ah)
>>>>>    hw.c helps
>>>
>>> please add this  before 2016, 2017 lines
>>>
>>> +pCap->tx_chainmask = 0x1;
>>> +pCap->rx_chainmask =0x1;
>>>>>
>>
>> I did that now the data stream seems to be going through antenna 0:
>>
>> 12:35:22.783976 599348659493us tsft 5240 MHz 11a 126dB signal antenna 0 [bit
>> 14] CF +QoS DA:...
>> 12:35:22.784021 599348659493us tsft 5240 MHz 11a 0dB signal antenna 0 [bit
>> 14] CF +QoS DA:...
>> 12:35:22.784064 599348660933us tsft 5240 MHz 11a -78dB signal antenna 0 [bit
>> 14] CF +QoS DA:...
>> 12:35:22.784109 599348660981us tsft 5240 MHz 11a -123dB signal antenna 0
>> [bit 14] CF +QoS DA:...
>> 12:35:22.784153 599348660981us tsft 5240 MHz 11a 2dB signal antenna 0 [bit
>> 14] CF +QoS DA:...
>>
>> However, I'm still receiving beacons through antenna 1:
>
> not much idea, probably we cannot change the rx mask i think. we can
> only change the tx mask?
> I heard this some senior eng saying this, but not sure. need to dig deep.
>
>>
>> 12:35:23.781184 599349658003us tsft 6.0 Mb/s 5240 MHz 11a -54dB signal
>> antenna 1 [bit 14] BSSID:...
>> 12:35:23.985982 599349862803us tsft 6.0 Mb/s 5240 MHz 11a -75dB signal
>> antenna 1 [bit 14] BSSID:...
>> 12:35:24.190791 599350067603us tsft 6.0 Mb/s 5240 MHz 11a -75dB signal
>> antenna 1 [bit 14] BSSID:...
>> 12:35:24.298133 599350174394us tsft 6.0 Mb/s 5240 MHz 11a -76dB signal
>> antenna 1 [bit 14] BSSID:...
>>
>> (btw, if you look at the signal levels on the topmost capture, they just
>> look insane. Could the reason be my setup: one interface is in station mode
>> transferring data, and other interface in monitor mode, watching the packet
>> flow. Is it possible TX is interfering RX signal measurements?)
>>
>> - Jussi
>>
>>
>>>>>
>>>>> 2016         tx_chainmask = pCap->tx_chainmask;
>>>>> 2017         rx_chainmask = pCap->rx_chainmask;
>>>>>
>>>>
>>>> Ok, thanks, I'll try with these changes.
>>>>
>>>> - Jussi
>>>>
>>>>>>
>>>>>> On 9 March 2011 18:48, Jussi Haakana<jussi.haakana at 7signal.com<mailto:jussi.haakana@7signal.com>>
>>>>>>   wrote:
>>>>>>>
>>>>>>> Hi,
>>>>>>>
>>>>>>> I have a setup in which I can connect only one
>>>>>>> antenna to AR9280 based card. Is there any way
>>>>>>> to force ath9k to use this antenna only? I'm not
>>>>>>> sure, but based on reported signal levels (tcpdump
>>>>>>> on monitor interface), it looks like the card tries
>>>>>>> to use both antennas even though there is only one
>>>>>>> antenna connected.
>>>>>>>
>>>>>>> I've read from earlier posts that this could be
>>>>>>> done by forcing rx/tx chainmasks to 1, does this
>>>>>>> apply to current ath9k version (wireless-testing)
>>>>>>> also? If I do this, does this have any side
>>>>>>> effects?
>>>>>>>
>>>>>>> - Jussi
>>>>>>> _______________________________________________
>>>>>>> ath9k-devel mailing list
>>>>>>> ath9k-devel at lists.ath9k.org<mailto:ath9k-devel@lists.ath9k.org>
>>>>>>> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> ath9k-devel mailing list
>>>>>> ath9k-devel at lists.ath9k.org<mailto:ath9k-devel@lists.ath9k.org>
>>>>>> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>>>>>>
>>>>>>
>>>>
>>>> _______________________________________________
>>>> ath9k-devel mailing list
>>>> ath9k-devel at lists.ath9k.org<mailto:ath9k-devel@lists.ath9k.org>
>>>> https://lists.ath9k.org/mailman/listinfo/ath9k-devel
>>>>
>>
>>
>
>