On Tue, 2009-01-13 at 14:28 -0800, Howard Chu wrote: > > Date: Tue, 13 Jan 2009 17:45:16 -0300 > > From: Aloisio Almeida<[email protected]> > > > Hi all, > > > > I noticed that wireless devices are always scanning, and this is very > > bad to power consuption in embedded systems. > > I would like to create a way to prevent automatic scan and just > > perform it when some cliente ask for it. > > Is it possible to do this? I mean, does it "brake" in some way the nm > > structure? > > > > Actually, I already did this patch to 0.6.6 version, but zero lines > > applied in new code :) Now i would like to create the patch and submit > > to upstream. > > > > The basic idea is just make can_scan function (src/nm-device-wifi.c) > > return FALSE due to some user configurations or run flags > > (--no-bg-scan). In this case, "performScan" dbus method and > > "ScanPerformed" dbus signal must be created to allow clients to ask > > for a scan and to notice that the scan has been performed. > > > > I'm attaching the 0.6.6 patch, as I said before the idea is the same. > > > > Any comments? Is it a good way to implement that? > > I also noticed that in NM 0.7 prereleases, scans did not occur on my ath9k > when it was associated, but after 0.7 was released, this behavior changed. (I > found the commit that changed this, saying it was removing a hack...) I > reinstated the hack on my build, because it was disrupting my streaming wifi > traffic. All in all, I would love to see scans only occurring on demand, and > not at any other time.
How long does the scan take on your ath9k card, and does buffering not paper over any momentary hiccups? Also, is your machine a desktop machine or laptop? Not scanning periodically means that NM (and the supplicant, and the driver) doesn't have a good picture of the network topology, and this can have adverse consequences for roaming and reconnection. If the driver is taking a long time to scan, then the driver may need some optimizations as well. The hack was there because long ago, madwifi simply couldn't scan in a reasonable amount of time. These days, almost all cards/drivers can scan in a reasonable amount of time, and those with hardware assisted scanning like Intel cards can do it even faster. Dan _______________________________________________ NetworkManager-list mailing list [email protected] http://mail.gnome.org/mailman/listinfo/networkmanager-list
