Re: [PATCH v3] ath10k: support NET_DETECT WoWLAN feature

[Brian Norris]

(I realize I replied to the v3, not the v4 which was merged.)

On Wed, Sep 18, 2019 at 7:03 AM Kalle Valo <kvalo@xxxxxxxxxxxxxx> wrote:
> Brian Norris <briannorris@xxxxxxxxxxxx> writes:
> > Since Wen has once again suggested I use this patch in other forums,
> > I'll ping here to note:
> >
> > On Wed, Nov 14, 2018 at 2:59 PM Brian Norris <briannorris@xxxxxxxxxxxx> wrote:
> >> You've introduced a regression in 4.20-rc1:
> >
> > This regression still survives in the latest tree. Is it fair to just
> > submit a revert?
>
> Your description about the problem from an earlier email:
>
>   "It seems like youre enabling SCHED_SCAN support? But you're not
>    adding the NL80211_FEATURE_SCHED_SCAN_RANDOM_MAC_ADDR feature flag.
>    So it puts us in a tough place on using randomization -- we either
>    can't trust the FEATURE flags, or else we can't use both SCHED_SCAN
>    and scan randomization."

Yeah, maybe I shouldn't have trimmed that context :)

> So essentially the problem is that with firmwares supporting both
> WMI_SERVICE_NLO and WMI_SERVICE_SPOOF_MAC_SUPPORT ath10k enables
> NL80211_FEATURE_SCAN_RANDOM_MAC_ADDR, but
> NL80211_FEATURE_SCHED_SCAN_RANDOM_MAC_ADDR is not enabled which is
> inconsistent from user space point of view. Is my understanding correct?

Yes, that sounds about right.

> Wen, can you enable NL80211_FEATURE_SCAN_RANDOM_MAC_ADDR? Does firmware
> support that?

I feel like I've asked him that privately, but asking here might not hurt :D

> If that's not possible, one workaround might to be to not enable
> NL80211_FEATURE_SCAN_RANDOM_MAC_ADDR if firmware supports
> WMI_SERVICE_NLO, but of course that would suck big time.

Yeah, that would be strictly worse than the current situation I think.
SCAN_RANDOM_MAC_ADDRESS is a product requirement for us. At least
right now, it's possible I could teach a user space to just ignore
SCHED_SCAN if it doesn't support the appropriate randomization
features. (I don't want to have to do that, but at least it's
possible.)

Brian

> Here's the full context in case someone is interested:
>
> https://patchwork.kernel.org/patch/10567005/