Re: Problem with brcmfmac removing extra interface

[Arend van Spriel <arend.vanspriel@broadcom.com>]

On 22-3-2016 7:36, Rafał Miłecki wrote:
> On 3 March 2016 at 23:37, Rafał Miłecki <zajec5@gmail.com> wrote:
>> brcmfmac in general is not capable of removing interfaces. If you take
>> a look at brcmf_cfg80211_del_iface implementation, you'll see it
>> returns -EOPNOTSUPP (except for p2p interfaces).
>>
>> However there is problem in handling NL80211_CMD_STOP_AP (with the
>> brcmf_cfg80211_stop_ap callback). Current implementation calls
>> brcmf_fil_cmd_int_set(ifp, BRCMF_C_DOWN, 1)
>> if mbss support is enabled/used.
>>
>> Above call results in firmware generating BRCMF_E_LINK event. This
>> event is handled with the following forward-traced functions chain:
>> 1) brcmf_notify_connect_status
>> 2) brcmf_notify_connect_status_ap
>> 3) brcmf_remove_interface
>> 4) brcmf_del_if
>> 5) brcmf_net_detach
>> 6) unregister_netdev
>>
>> So the result of NL80211_CMD_STOP_AP is interface being removed. The
>> problem with this behavior is that interface can't be recreated after
>> that:
>> # iw phy phy1 interface add wlan1-1 type __ap
>> [ 3602.929199] brcmfmac: brcmf_ap_add_vif: timeout occurred
>> command failed: I/O error (-5)
>>
>> I hit this problem when trying to restart hostapd using BCM43602 and 2 BSSes.
>>
>> Could you analyze this problem and see if you see some way of solving
>> this problem, please?
> 
> Hi, any ideas / help regarding this issue?

Restarting hostapd obviously is a valid scenario. My guess is we would
need to avoid interface removal in brcmf_notify_connect_status_ap. But
first I would like to know in which state the firmware is upon
brcmf_ap_add_vif. Can you provide a full log with FWCON debug level enabled?

Regards,
Arend