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. Keeping the STA aside, as far as AP is concerned the STA is still in PS, so it should set the TIM/DTIM bit to 1 before sending out data to the STA. Because the STA might be in power-off mode things seem to work.
