On Tue, Oct 11, 2016 at 10:12 PM, Arend van Spriel <arend.vanspriel@xxxxxxxxxxxx> wrote: > On 07-10-16 16:33, Gucea Doru wrote: >> On Thu, Oct 6, 2016 at 10:25 AM, Arend Van Spriel >> <arend.vanspriel@xxxxxxxxxxxx> wrote: >>> On 6-10-2016 10:07, Gucea Doru wrote: >>>> On Wed, Oct 5, 2016 at 11:12 AM, Arend Van Spriel >>>> <arend.vanspriel@xxxxxxxxxxxx> wrote: >>>>> On 4-10-2016 13:39, Gucea Doru wrote: >>>>>> On Sat, Oct 1, 2016 at 2:52 PM, Arend van Spriel >>>>>>> <arend.vanspriel@xxxxxxxxxxxx> wrote: >>>>>>>> >>>>>>>> >>>>>>>> On 29-09-16 13:32, Gucea Doru wrote: >>>>>>>>> On Tue, Sep 27, 2016 at 12:03 PM, Gucea Doru <gucea.doru@xxxxxxxxx> 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
