Hi again,

According to the comments for BackgroundScanning 

# Enable background scanning. Default is true.
# Background scanning will start every 5 minutes unless
# the scan list is empty. In that case, a simple backoff
# mechanism starting from 10s up to 5 minutes will run.

I would assume that connman should detect when the list is empty and trigger a scan but what we are experiencing is that it will only trigger a scan every 5 minute no mater if the list is empty or not. Is this how it is intended?

BR
Måns Zigher



Den mån 27 aug. 2018 kl 12:51 skrev Julien Massot <jmassot@softbankrobotics.com>:
Hi Måns,

On Mon, Aug 27, 2018 at 6:23 AM, Måns Zigher <mans.zigher@gmail.com> wrote:
> Hi Daniel,
>
> Thanks for your time I appreciate it. On our target what I can see is that
> if I let connman/wpa_supplicant manage the scanning I end up with an empty
> list frequently which then causes my application to fail since it cannot
> find the service to connect to. Is this is a bug or is this a situation that
> my application need to take into consideration and if so the action to take
> is to trigger a scan?

wpa_s remove bss from the list after a delay of 180s
(DEFAULT_BSS_EXPIRATION_AGE), defined here:
https://w1.fi/cgit/hostap/tree/wpa_supplicant/config.h

ConnMan have a delay of 300 seconds maximum between two scan, so the
list maybe empty.

Increasing the delay between two scan may reduce the bandwidth or can
cause beacon miss.

Up to your choice for your application, reducing the maximum scan time
of the autoscan
(used when not connected to any WiFi network) may be a good idea.
If you want to scan more often when connected change
the BGSCAN_DEFAULT macro to something lower than 180.
(look at plugins/wifi.c)

You can also change wpa_supplicant configuration to increase expiration age.

If your list should be complete at some moment, like configuration purpose.
Launch manually a scan using ConnMan dbus interface net.connman.Technology.

And yeah I agree with Daniel this WiFi plugin code is terrible,
especially about scanning.
Can't wait to give a try to iwd, and hope this scan mess is better handled.

Best Regards,
Julien

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