NL80211_ATTR_PREV_BSSID on resume

Carlo Caione carlo at
Thu Jan 25 09:12:11 PST 2018

I'm not sure if this is a wpa_supplicant or a driver problem but I'd
like to discuss this a bit here since I'm missing familiarity with
NL80211 to define where the problem actually is.

In Endless we are facing a problem with an hardware shipping a
RTL8723BU WiFi module. Since the upstream drivers are not working fine
we resorted to use the downstream driver at [0].

This driver is usually working fine with a big problem though: when
resuming the machine from suspend, nm fails to connect again to the
AP. As you can see in [1] we are not the only ones experiencing this

I bisected this issue down to the upstream commit in [2]. In
particular AFAICT the problem is triggered by the line in [3] since
(as you can see in [4]), the NL80211_ATTR_PREV_BSSID attribute is not
set on connect. AFAICT wpa_supplicant is perfectly able to set the
NL80211_ATTR_PREV_BSSID on connect but it is not doing that on resume
from the logs I collected (if you are interested in [5] the
wpa_supplicant log after the resume).

Now I'm wondering where the problem is. For sure something is wrong in
the driver (otherwise I would have seen much more complains around
with other drivers) but it's still not clear to me what's the matter
with NL80211_ATTR_PREV_BSSID and if wpa_supplicant is supposed to set
the attribute when connecting and especially after a resume.

Thank you,


Carlo Caione  |  +44.7384.69.16.04  |  Endless

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