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[Tony Espy <1480877@xxxxxxxxxxxxxxxxxx>]

I installed bustle on my krillin this afternoon to try and glean some
more information from the system DBus.   I few observations...

1. The top signal on the system bus is:

org.freedesktop.NetworkManager.AccessPoint.PropertiesChanged

2. Most of these seem to be for a specific AP ( instance 0 ), which I'm
pretty sure is the current connected AP.  The associated property is
'Strength'.   This makes sense, as NM constantly reports the varying
signal strength of the AP.    These are happening all the time, and I
typically see them in bursts of two or three signals.

3. As scans typically occur anywhere from 20s to 2m, when they do occur,
we see a flurry of AccessPoint.PropertiesChanged signals representing
the changing signals strengths of each access point.  There also are
AccessPoint.PropertiesChanged signals for the 'LastSeen' property.  I'm
pretty sure this property was added specifically for the
LocationService.  Note, ideally this signal would be bundled with the
associated 'Strength' signal, however due to the way NM's underlying
object/property system was architected, this doesn't seem to be an easy
change at first glance.  Note, these LastSeen signals are consumed by
the LocationService's 'connectivity API' ( which I'm pretty sure uses
dbus-cpp ).

So... we still need to quantify how many APs trigger the problem, and if
it's being triggered whenever scans occur.  In comment #29, Pat
mentioned that it happened when he initially arrived in Bluefin, but
went away once he connected to an AP.   As background scanning had
recently been restored in NM, I would've assumed he would continue to
see the issue each time a scan was occurred, even when connected.

It also would be interesting to see whether disabling location service
has any effect on the problem ( if we can reproduce reliably of course
).

Perhaps I can dummy up wpa_supplicant to push an artificial number of
APs to NM and see if I can trigger the problem locally.

-- 
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Packages, which is subscribed to network-manager in Ubuntu.
https://bugs.launchpad.net/bugs/1480877

Title:
  Access points' "PropertiesChanged" dbus signals freeze UI on mobile
  devices

Status in Canonical System Image:
  Confirmed
Status in indicator-network package in Ubuntu:
  Incomplete
Status in network-manager package in Ubuntu:
  Incomplete

Bug description:
  Krillin, rc-proposed, r83

  
  DESCRIPTION:
  I've been trying to track down the cause of the occasional UI freezes on my Krillin device, and I noticed that whenever the UI freezes for 2-4 seconds, I get a burst of "PropertiesChanged" signals in dbus-monitor

  Here's a log of what's shown in dbus-monitor:
  http://pastebin.ubuntu.com/11992322/

  I'd guess the problem is in the code that actually catches the signals
  and acts accordingly.

  HOW TO REPRODUCE: 
  1) Move to a place where many wifi hotspots are available
  2) Connect the device via USB and run "phablet-shell" and then "dbus-monitor"
  3) Use the device while keeping an eye on dbus-monitor output

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