All,
On 2/12/24 5:36 PM, KeithG wrote:
I have been trying to use teh brcmfmac device on my RPi to run in AP
mode to allow device configuration of wifi and such when ethernet is
not available. I am using connman and iwd to manage my internet
connections and have noticed that when the AP is running, the AP will
reset when iwd scans.
I set it up to be an AP so I can configure the network on the RPi via
a web interface. I first set up a as a separate device as an AP for
wlan0:
iw dev wlan0 interface add ap0 type __ap
I then give it a MAC different from the wlan0 so iwd can keep track of
which is which and the ssids will show up on wlan0 when I run 'iwctl
station wlan0 scan'
ip link set dev ap0 address b8:27:eb:00:00:00
I then start an AP with either iwd or hostapd/dnsmasq.
iwctl device ap0 set-property Mode ap
iwctl ap ap0 start-profile testAP
It will start the AP and then I can connect to the Pi from my laptop.
I am using iwd on wlan0 to scan for available SSIDs. Whenever iwd
scans, either manually from cli or automatically, it will reset the AP
and kick everyone off. It does this even when I use hostapd/dnsmasq to
control the AP. When I disable iwd and use wpa_supplicant for
scanning, though, I can set up the AP with hostapd and scan many times
via connmanctl and it will not disconnect.
Why does it kick everyone off when iwd scans? Why is iot more stable
with wpa_supplicant? Is there something I could/should do to make this
more stable? When I try this on an intel card, it is rock steady and I
have not seen a disconnect. I have tried the latest brcmfmac
(cycmfmac) firmware and see the same result.
https://github.com/Infineon/ifx-linux-firmware/tree/master/firmware
I am running RPiOS Bookworm and am fully up to date though it uses an
older firmware
[ 11.513277] brcmfmac: F1 signature read @0x18000000=0x1542a9a6
[ 11.533628] brcmfmac: brcmf_fw_alloc_request: using
brcm/brcmfmac43430b0-sdio for chip BCM43430/2
[ 11.740252] brcmfmac: brcmf_c_preinit_dcmds: Firmware: BCM43430/2
wl0: Mar 31 2022 17:24:51 version 9.88.4.77 (g58bc5cc) FWID
01-3b307371
Is there any hope of stability when used like this?
Keith
I was helping Keith out here and wanted to provide a bit more
information. I found there were a few differences between IWD and
wpa_supplicant related to scanning which may aid in figuring out why
brcmfmac is behaving this way:
- IWD scans using the wdev ID where wpa_supplicant uses ifindex. Not
sure if this has anything to do with the difference behavior.
- Passive scans (which IWD prefers) seem to exacerbate the behavior.
Simple testing using "wpa_cli scan" showed wpa_supplicant was only using
active scans. I also tested with iw and saw repeatable disconnects when
passive scanning. Disconnects while using active scans (using iw) were
much less frequent.
- Scanning with IWD, wpa_supplicant, or iw, passive or active, always
resulted in beacon loss for clients connected to the AP. This was 100%
guaranteed. The clients just could recover when active scans were used
over passive. But either way this does not seem like normal behavior,
the AP interface should still be beaconing on its active channel during
a scan right? If this isn't possible or can't be done reliably then
should the interface combinations be changed to disallow concurrent sta
+ AP mode interfaces?
Thanks,
James
