Re: Export "scan now" command over D-Bus

[Dan Williams <dcbw redhat com>]

On Thu, 2009-03-26 at 17:42 -0400, C. Scott Ananian wrote:
> We're developing a custom UI for an embedded device, and would like to
> provide a "Scan Now" button in the UI to force an immediate rescan of
> the wireless network.  This feature may be generally useful: certainly
> I often see stale networks on my laptop when I resume from suspend,
> and it would be nice not to have to wait 20s for the next scheduled
> scan.
> 
> The attached patch is very small, as the functionality is already
> present in network-manager, just not exported.  Comments?

Go read the NM list archives as to why there's no scan now button.
Insta-scan is not the cure for all your problems... :)

I will, however, port the NM 0.6 "user interacted with me, maybe you
want to scan a bit faster" hint for the applet/user-settings-service
that didn't get into 0.7.  NM will then trigger a scan either
immediately (if the last scan was more than 20 seconds ago) or 20
seconds from the last scan.  Scanning is effectively a DOS remember, so
it's not something you want to do often or when you're using VOIP or
ssh.

The "stale networks on resume" is not an NM problem but a kernel bug;
you'll want to fix your drivers.  Please see:

http://blogs.gnome.org/dcbw/2009/02/26/suspendresume-vs-networkmanager/
https://bugzilla.redhat.com/show_bug.cgi?id=466136
http://git.kernel.org/?p=linux/kernel/git/linville/wireless-testing.git;a=commit;h=5c839f67c6e78ac9db8282102269886777d2d481
http://git.kernel.org/?p=linux/kernel/git/linville/wireless-testing.git;a=commit;h=4c18c8baf0a9f7bf6b0792ad7c7f0089254fe516

Dan