On Fri, Mar 04, 2016 at 10:07:56AM +0200, Luca Coelho wrote:
> On Fri, 2016-02-26 at 22:12 +0200, Jouni Malinen wrote:
> > This is an optimization and as such, it is acceptable for some of the
> > drivers not to support the mechanism. If not supported, the wildcard
> > BSSID will be used and more responses may be received.
>
> Receiving more responses than what we asked for is always possible,
> because we don't filter out other things we may receive at the same
> time. It's like requesting for a specific SSID, it just means that the
> SSID will be used in the probe requests, but it doesn't guarantee that
> other results will not be returned.
Sure. This "more responses" is referring to not being able to get the
benefit from saved airtime; not on what we might add into the cfg80211
BSS table. We don't even have an explicit mechanism for reporting
results from a single scan iteration.
> > diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
> > @@ -322,7 +322,9 @@
> > * @NL80211_CMD_GET_SCAN: get scan results
> > * @NL80211_CMD_TRIGGER_SCAN: trigger a new scan with the given parameters
> > * %NL80211_ATTR_TX_NO_CCK_RATE is used to decide whether to send the
> > - * probe requests at CCK rate or not.
> > + * probe requests at CCK rate or not. %NL80211_ATTR_MAC can be used to
> > + * specify a BSSID to scan for; if not included, the wildcard BSSID will
> > + * be used.
>
> Maybe you could be explicit here about the possibility of receiving
> more results than requested?
Which "receiving" are you referring to here? I don't see much point in
documenting the airtime optimization here and as far as receiving
results through nl80211 is concerned, the only option for it today is to
use NL80211_CMD_GET_SCAN and that returns the current contents of the
BSS table rather than returns from any specific scan, so I'm not sure
what exactly you would like to add here.
I was going to note that this is similar to how NL80211_ATTR_SCAN_SSIDS
is documented, but actually, that one is not mentioned at all with
NL80211_CMD_TRIGGER_SCAN currently.. Nor is the details of what
NL80211_CMD_GET_SCAN returns.
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