On Tue, Oct 11, 2016 at 10:12 PM, Arend van Spriel
<arend.vanspr...@broadcom.com> wrote:
> On 07-10-16 16:33, Gucea Doru wrote:
>> On Thu, Oct 6, 2016 at 10:25 AM, Arend Van Spriel
>> <arend.vanspr...@broadcom.com> wrote:
>>> On 6-10-2016 10:07, Gucea Doru wrote:
>>>> On Wed, Oct 5, 2016 at 11:12 AM, Arend Van Spriel
>>>> <arend.vanspr...@broadcom.com> wrote:
>>>>> On 4-10-2016 13:39, Gucea Doru wrote:
>>>>>> On Sat, Oct 1, 2016 at 2:52 PM, Arend van Spriel
>>>>>>> <arend.vanspr...@broadcom.com> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> On 29-09-16 13:32, Gucea Doru wrote:
>>>>>>>>> On Tue, Sep 27, 2016 at 12:03 PM, Gucea Doru <gucea.d...@gmail.com> 
>>>>>>>>> wrote:
>>>>>>>>>> What is the decision triggering the exit from the PS mode immediately
>>>>>>>>>> after the ping request? I am asking this because 802.11 PS legacy
>>>>>>>>>> specifies that the client should wait for a beacon with TIM set in
>>>>>>>>>> order to wake up: in my case, there is no beacon between the ping
>>>>>>>>>> request message and the Null frame that announces the exit from the 
>>>>>>>>>> PS
>>>>>>>>>> mode.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Any help would be highly appreciated :)
>>>>>>>>
>>>>>>>> Actually though I already sent you are reply, but alas here it is.
>>>>>>>>
>>>>>>>> bcmdhd is our aosp driver. I am maintaining the upstream brcm80211
>>>>>>>> drivers. Regardless your question is more for firmware running on the
>>>>>>>> device. So like the same behavior would be observed when using brcmfmac
>>>>>>>> with same firmware.
>>>>>>>>
>>>>>>>>> IEEE Std 802.11-2012, section 10.2.1.8 specifies that "when the STA
>>>>>>>>> detects that the bit corresponding to its AID is 1 i the TIM, the STA
>>>>>>>>> shall issue a PS Poll". In my capture there are cases when the STA
>>>>>>>>> exits the PS mode without waiting for a beacon.
>>>>>>>>
>>>>>>>> It is a bit tricky, but the standard does not explicitly say the STA
>>>>>>>> should be in power-save at any other time. So it is difficult to say
>>>>>>>> what event occurred on the STA side to exit PS mode. Also STA means
>>>>>>>> P2P-Client as you say. That means that you have multiple interfaces:
>>>>>>>> regular STA and P2P-Client. So is the STA connected to some other AP or
>>>>>>>> just not connected. wpa_supplicant will do intermittent scan or 
>>>>>>>> initiate
>>>>>>>> scheduled scan by which firmware will scan at a certain interval. That
>>>>>>>> is just some things I can come up with and I am sure there are more.
>>>>>>
>>>>>> I agree that there may be some events belonging to the regular STA
>>>>>> interface that could trigger the Null Frame (which includes the exit
>>>>>> from PS Mode). However, I would expect to see some management frames
>>>>>> in the air before/after the Null Packet (e.g.: a Probe request in case
>>>>>> of a scheduled scan). But in my case the trigger for the Null frame
>>>>>> seems to be the ping request packet, the scenario is the same every
>>>>>> time: ping request -> Block ACK -> Null Frame (Wireshark trace
>>>>>> confirms this behavior).
>>>>>>
>>>>>> I thought that you had a power save optimization algorithm that keeps
>>>>>> the card on a few milliseconds just to see if we can have a fast reply
>>>>>> from the peer. Does this ring a bell? :)
>>>>>
>>>>> It does not. That would be implemented in firmware. As said I am working
>>>>> on brcmfmac/brcmsmac. So bcmdhd and firmware are not my expertise.
>>>>>
>>>>
>>>> Arend, could you please redirect me to a Broadcom firmware maintainer?
>>>
>>> Can you please elaborate on your platform, broadcom chipset, and what
>>> version of bcmdhd you are using.
>>>
>>
>> Platform: Nexus 5 running CM13 (Android 6.0.1)
>> Broadcom chipset: BCM4339 Wi-Fi Chipset
>> bcmdhd version:Dongle Host Driver, version 1.88.45 (r)
>>
>> Do you need more information?
>
> So can you indicate the mac addresses of the two nexus devices and which
> one is P2P-GO. I entered the wpa key you mentioned in your initial
> email, but my wireshark does not seem to be able to decrypt the packets,
> which makes it a bit harder to analyze.

Do you have a wpa-pwd entry "JYdrhZp3:DIRECT-35-Android_Intel" inside
Edit->Preferences->Protocols->IEEE 802.11->Decryption Keys? I use
Wireshark 2.0.4.

P2P-GO MAC: 66:89:9a:81:0d:95
P2P Client MAC: 66:89:9a:81:0f:20

Thanks,
Doru

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