VHT 160Mhz and nss related config.

Sebastian Gottschall s.gottschall at dd-wrt.com
Tue Feb 14 02:19:30 PST 2017


now the test result. yes. it assocs with VHT160 SGI in my case. but 
performance is as expected identical to VHT80

Am 14.02.2017 um 00:12 schrieb Ben Greear:
> On 02/13/2017 02:48 PM, Sebastian Gottschall wrote:
>> Am 13.02.2017 um 20:56 schrieb Ben Greear:
>>> On 02/11/2017 10:21 AM, Sebastian Gottschall wrote:
>>>> Am 11.02.2017 um 18:58 schrieb Ben Greear:
>>>>> On 02/10/2017 08:37 PM, Adrian Chadd wrote:
>>>>>> On 10 February 2017 at 20:22, Sebastian Gottschall
>>>>>> <s.gottschall at dd-wrt.com> wrote:
>>>>>>> i really can't believe this. if this is true the  160 mhz mode 
>>>>>>> would not
>>>>>>> make any sense.
>>>>>>> the maximum tx / rx rate for 4x4 vht80 and 2x2 vht160 is 
>>>>>>> identical. so
>>>>>>> vht160 would not increase performance in any way
>>>>>>
>>>>>> Well, if it can also do 2x2 MU-MIMO at 160MHz then it can be a
>>>>>> perfectly fine STA to a 4x4 160MHz MU-MIMO chip that can actually
>>>>>> transmit 2x2 rates to different MU-MIMO peers.
>>>>>>
>>>>>> That's the outstanding question I have - is it like, 2x2 MU only, or
>>>>>> is it say, 2 concurrently different spatial stream 2x2 MU? Ie, 
>>>>>> can you
>>>>>> have 2 peers, different VHT spatial groups (or 4 peers, 1 spatial
>>>>>> group each) all going at the same time?
>>>>>>
>>>>>> I'm .. not even sure how you're supposed to cleanly negotiate 
>>>>>> that you
>>>>>> can do 4NSS in VHT80 but 2NSS in VHT160 to a peer... that only makes
>>>>>> sense if you're doing lots of 1NSS and 2NSS MU-MIMO peers..
>>>>>
>>>>> I think using the max-rx-rate logic might could imply this, but I 
>>>>> am not sure
>>>>> many drivers fill this out properly.
>>>>>
>>>>> Looks like a mess waiting to happen to me.
>>>>>
>>>>> Even if you can do 1x1 160Mhz MU-MIMO to two stations, and I am 
>>>>> not certain you
>>>>> can since in 80Mhz you can only do a 1x1 and a 2x2 (not two 2x2).
>>>>>
>>>>> So, from what I know currently, 80+80 is not that useful on the 
>>>>> 9984 NIC...
>>>> never tried 80+80 since i need to enhance the channel logic alot in 
>>>> my firmware code to handle it. would be great enough if vht160 
>>>> would work as expected and
>>>> i'm not sure right now if it really works, even if the interface 
>>>> initialized correctly it assocs only with vht80
>>>
>>> Looks like it is working with the hack I posted:
>>>
>>> Station 04:f0:21:2e:49:65 (on wlan2)
>>>     inactive time:    0 ms
>>>     rx bytes:    64902998
>>>     rx packets:    37918
>>>     tx bytes:    64760298
>>>     tx packets:    42239
>>>     tx retries:    0
>>>     tx failed:    0
>>>     signal:      -43 dBm
>>>     signal avg:    -42 dBm
>>>     tx bitrate:    1053.0 MBit/s VHT-MCS 6 160MHz VHT-NSS 2
>>>     rx bitrate:    1560.0 MBit/s VHT-MCS 8 160MHz short GI VHT-NSS 2
>>>     authorized:    yes
>>>     authenticated:    yes
>>>     preamble:    long
>>>     WMM/WME:    yes
>>>     MFP:        no
>>>     TDLS peer:    no
>>>     connected time:    156 seconds
>>>
>>> Thanks,
>>> Ben
>>>
>>>
>> the hack you posted crashes the driver for me. i also see that this 
>> patch is based on the CT ath10k source. it doesnt apply clean to 
>> ath10k. needed to merge it
>> manually
>
> Ok, I'm in the middle of a bunch of changes to support VHT overrides 
> to allow
> disabling VHT160/80+80 in station mode, and I'll push all my changes 
> to my
> tree when I get that implemented and testing.
>
> I've about given up on getting ath10k patches upstream, but I'll get 
> these changes into
> ath10k-ct in LEDE sometime...
>
> If you want to post the splat, just possibly I'll have a quick idea of 
> why it
> is crashing.
>
> Thanks,
> Ben
>
>


-- 
Mit freundlichen Grüssen / Regards

Sebastian Gottschall / CTO

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