Re: Scannning

[Dan Williams <dcbw redhat com>]

On Mon, 2007-03-19 at 14:48 +0200, Tambet Ingo wrote:
> Here's how scanning is scheduled:
> 
> When the nm-applet's devices menu is expanded, NetworkManager
> schedules a scan to start in 20 seconds. If the menu is deactivated
> and activated again within that 20 seconds, NM re-schedules the scan
> after another 20 seconds. So if you keep clicking on applet with
> intervals less than 20 seconds, the NM initiated scan never happens.
> When the scan is actually initiated, it takes a bit time to get the
> results back and it depends on wireless driver how fast/slow it is. If
> the menu is still expanded, the scan results are not added to the
> menu, you have to deactivate the menu and activate it again to see the
> results (and a new scan is scheduled again). 

Right, there are bugs in the scan algorithm like this one that should
get fixed, but before that we needed to determine exactly _how_ it
should best get fixed, which I think we now know.  We'd have problems if
people wanted very short scan intervals while connected, which doesn't
appear to be the case.

For 0.6.x at least, I think we can get a good enough patch.

Dan


> There are multiple problems when trying to "fix" this behavior:
> 
> * Scanning disables all other operations on card so network doesn't
> work at that time. That's the reason there is a timeout, that's the
> reason there can't be a "scan now" button (well, part of the reason
> anyway). We need to protect NM from malicious users who can write a
> shell script to make NM scan constantly (or if they're not smart
> enough, keep hitting that button/activating the menu manually). [1] 
> 
> * The devices menu is a GtkMenu widget which means the changes made to
> the menu (adding/removing menu items) while it's expanded doesn't
> change it's appearance until it's shown next time. Another
> difficulties are to keep the menu sorted correctly, replace the labels
> of devices (there's a generic and specific variants, depending on the
> number of same type devices). Nothing impossible, just requires a lot
> of work and while the SVN trunk barely works at the moment, it's
> doesn't make sense to work on that right now. 
> 
> [1] I'm not sure how serious that is since any user can just
> deactivate all networking anyway.
> 
> Tambet
> _______________________________________________
> NetworkManager-list mailing list
> NetworkManager-list gnome org
> http://mail.gnome.org/mailman/listinfo/networkmanager-list