Re: Slow wifi-reconnection when waking up
On Wed 22 Jul 2020 at 15:04:44 (-0400), Stefan Monnier wrote:
> When I wake up from suspend, my Debian machines take a "long" time to
> reconnect to the wifi. Looking at the `nm-applet` icon in my XFCE4
> panel, I see:
> - for about 10s the icon is "two computers" (which IIUC represents
> just NetworkManager).
> - then the icon changes to the one representing a wired ethernet
> connection and stays that way for about 10s (there's nothing
> plugged into the ethernet port of this computer).
> - then the icon changes to the "two dots, with something circling
> between them" which indicates that the system is in the process of
> connecting to a wifi network.
> - after about 5s this changes to the bars representation of the
> signal quality.
>
> IOW, while it takes about 5s to connect to the wifi network, it takes
> about 20 additional seconds for NM to decide that it should try to
> connect.
>
> I have the impression that a few years ago, my Debian machines
> reconnected more quickly to the wifi.
>
> I can live with this delay, especially when it's waking up in
> a different place than where it got suspended, but in the case where
> it's waking up at the same place where it got suspended, those extra 20s
> seem hard to justify.
>
> Any idea what might be going on and how to make it quicker?
Presumably the logs (daemon.log, syslog) should give details of
what's going on. But I'm not clear about how it should determine
that it woke up in the same place, except by first checking for a
wired connection (if you have that configured and prioritised), and
then negotiating a wireless connection.
All my machines, wired and wireless, negotiate DHCP leases with my
routers (so some of the timings I observe may be slowed by the
cascading involved). I don't know whether you can manually configure
an alternative, more static, type of connection that would be faster
coming up.
If you normally never use a wired connection, you might consider
blacklisting the appropriate ethernet module via a kernel parameter
(module_blacklist). That would allow you to set up alternatives as
Grub menu items.
Cheers,
David.
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