Re: brcmfmac disconnects when iwd scans

On Wed, May 7, 2025 at 2:44 PM KeithG <[email protected]> wrote:
>
> On Wed, May 7, 2025 at 9:27 AM Arend van Spriel
> <[email protected]> wrote:
> >
> > On 5/7/2025 3:54 PM, KeithG wrote:
> > > further information...
> > >
> > > I tried this with 2 different pi4s and have been able to confirm
> > > wpa_supplicant/hostapd is stable on the Pi4 (will try others when I
> > > get a chance). I also tried both the 'shipping' brcmfmac43455 firmware
> > > and the 'latest'. It is only with the 'latest' that I get reliable
> > > connections. With the 'shipping' version, I can get connections for
> > > both wlan0 with wpa_suppolicant and ap0 with hostapd, but the ap0
> > > connection is flaky without any connection on wlan0. And I cannot
> > > sustain both connections at all. This 'latest' firmware is required
> > > for a sustainable, reliable ap0 with connection with hostapd.
> > >
> > > this is the firmware required:
> > > [    3.658201] brcmfmac: brcmf_fw_alloc_request: using
> > > brcm/brcmfmac43455-sdio for chip BCM4345/6
> > > [    3.660643] usbcore: registered new interface driver brcmfmac
> > > [    4.041524] brcmfmac: brcmf_c_process_txcap_blob: no txcap_blob
> > > available (err=-2)
> > > [    4.042269] brcmfmac: brcmf_c_preinit_dcmds: Firmware: BCM4345/6
> > > wl0: Oct 28 2024 23:27:00 version 7.45.286 (be70ab3 CY) FWID
> > > 01-95efe7fa
> > >
> > > The only annoyance I get is that the log fills up with failed scan messages:
> > > May 07 08:43:11 deskrune wpa_supplicant[604]: wlan0: Failed to
> > > initiate sched scan
> >
> > The scheduled scan is basically a scan offload in which user-space tells
> > the driver what to look for and how often (hence scheduled). The
> > advantage of the scheduled scan is that the host (RPi) goes to sleep
> > while the wifi chip is on the lookout for the ssid. No idea why it is
> > failing though.
> >
> > > the Pi still works and is scanning because when a known ssid appears,
> > > it immediately connects, so it is scanning, I just get this message.
> >
> > What I recall from wpa_supplicant behavior is that it does a regular
> > scan for a configured ssid and after a number of attempts it does try to
> > setup a scheduled scan if the driver supports it. When it fails it
> > simply continues with the regular scans. The brcmfmac driver supports
> > scheduled scan so it seems like regression although apart from the log
> > message the end-user is not really affected. I expect it will not make
> > much noticable difference on the energy bill. ;-)
> >
> > > Now that I have this working well with wpa_supplicant and know how to
> > > get it all 'up' and stable, I will start investigating what
> > > differences there are with iwd and why it is flaky. Please guide me as
> > > to the best way to do this.
> >
> > Were you successful using nlmon. I suspect differences should show up
> > between wpa_supplicant and iwd.
> >
> > Regards,
> > Arend
>
> I will use nlmon and see what the difference is. Will post them when I get them.
>
> Keith

This is an iwmon log showing the hostapd up then a connection from my
laptop then a wpa_supplicant connection to my phone acting as a hot
spot.

https://drive.google.com/file/d/12NhxYT-gF0K2NrBfYEpSvcuGQ6UyejQD/view?usp=sharing

This is an iwmon log showing the same activities, but with iwd
managing the ap. The laptop connecting, then connecting to the phone
as a hot spot. Both disconnected. and passed no data.

https://drive.google.com/file/d/1diSp32FXpHjLzQeC5gF-tlNNHji8a1l5/view?usp=sharing

I do not know how to read these, but hopefully they will provide some guidance.

Keith