Hi Johannes, On Mon, Dec 5, 2016 at 6:28 AM, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote: > Hi Dmitry, > > Sorry I didn't respond earlier. > >> Currently we have sched scan with possibility of various >> intervals. We would like to extend it to support also >> different types of scan. > > "Different types of scan" is a bit misleading though, isn't it? I mean, > mostly they differ in the reporting modes - the scanning itself still > happens at "various intervals"? > >> In case of powerful wlan CPU, all this functionality >> can be offloaded. >> In general case FW processes additional scan requests >> and puts them into queue based on start time and interval. >> Once current request is fulfilled, FW adds it (if interval != 0) >> again to the queue with proper interval. If requests are >> overlapping, new request can be combined with either one before, >> or one after, assuming that requests are not mutually exclusive. >> Combining requests is done by combining scan channels, ssids, >> bssids and types of scan result. Once combined request was fulfilled >> it will be reinserted as two (or three) different requests based on >> their type and interval. >> Each request has attribute: >> Type: connectivity / location > > I'm not super happy with this - after all, in theory nothing precludes > using the results for one thing or the other, it's just about when and > how they are gathered, no? Indeed, results are results. I just want to take care of two things: 1) Memory consumption - we can clear stale scan results for connection, but not for location if we are using history scan. 2) Use of insufficient results for connection - in case we had history or hotlist scan only for very limited amount of channels, then we may not have enough APs in our result for "sterling" connection decision. > You do have a point wrt. an incomplete scan triggering something wrt. > roaming or so in the connection manager, but I think that if it finds a > better result there than the current connection it would make sense to > pick it - even without full information. > > So ultimately, I think this might boil down to reporting the scan > finished more accurately/precisely, rather than saying the type of > scan? This is intertwined with Luca's and yours point below - to use scan by name or by description of the actions. Indeed maybe this way is more generic and more useful. >> Report: none / batch / immediate > > Not sure I see much point in "none"?? > > Can you define these more clearly? Do you think "batch" reporting > should be like the gscan buckets? Or actually have full information? None - means that there is not need to report. It can be useful in case of roaming scan, scheduling or hotlist scan - you didn't find anything suitable - don't report that there is no scan results. Batch - means to report only when buffer is full (or close to full) - mostly for history scan or for example for case to report all scan results together. Immediate - is kind of self-explaining. >> Request may have priority and can be inserted into >> the head of the queue. >> Types of scans: >> - Normal scan >> - Scheduled scan >> - Hotlist (BSSID scan) >> - Roaming >> - AutoJoin > > I think somebody else said this but I didn't find it now - I think this > would make more sense to define in terms of expected behaviour than use > cases for each type of scan. I think Luca made this statement. It is totally ok from SW point of view - especially due to the fact that scan is scan. However, I suspect it will be harder to handle from user experience. I mean at the end wireless framework / driver / FW will convert special scan type to usual scan with special params and response, but why to put this burden on user? Anyway, I am ok with this approach as well. If we see that it is confusing we can use scan wrappers. > johannes >
