GNOME Bugzilla – Bug 693513
Provide an option to manually scan networks
Last modified: 2013-02-15 19:56:39 UTC
Currently there is no option to manually scan for wireless networks from network manager and we just have to wait until it scans automatically next time. I have to go to command line and run iwlist scan to do the scan. This is irritating as I have to do it every time I start wireless tether from my mobile phone. I think this would be a common use case for anyone using their mobile phone tethering to get online. Please add an option to scan networks as wireless network is activated after network manger is started most of the time and next scan is indeterminate.
Manual scanning is implemented: RequestScan D-Bus method for NM daemon: http://cgit.freedesktop.org/NetworkManager/NetworkManager/commit/?id=5e3e19d02b4884a2cb8429ff384d28dbcd9e3feb libnm-glib add nm_device_wifi_request_scan_simple() function: http://cgit.freedesktop.org/NetworkManager/NetworkManager/commit/?id=e837098b0004fc8b2943cd099dc5238f54a9e572 and nmcli support will follow soon: http://cgit.freedesktop.org/NetworkManager/NetworkManager/commit/?h=cli-enhance&id=a5ab745283c2ae764361d61ba23064527beb41a3 Also some fixes to automatic scanning that should resolve many issues: http://cgit.freedesktop.org/NetworkManager/NetworkManager/commit/?id=0e262e04e1800f312d4c40c07b6394ffacb2d34d http://cgit.freedesktop.org/NetworkManager/NetworkManager/commit/?id=f83ae16d10b958fe04fd7197547731679942a9fc Interestingly, there are also opposite request, e.g. to have a means to inhibit scanning. This is probably due to buggy drivers that could have problems while scanning is performed (even if NM does background scanning). I heard that while scanning networks on iw3945 while connected, the latency is increased. And the cause problem e.g. for VoIP applications.
Scan inhibit is best solved at the driver level by ensuring that background scanning does not increase connection latency. Plus, if you lock the connection to a BSSID, NetworkManager will not scan on that connection, so thats pretty much the way to inhibit scanning.