On Tue, 2009-04-07 at 15:13 +0200, Johannes Berg wrote: > On Tue, 2009-04-07 at 16:04 +0300, Maxim Levitsky wrote: > > > > > > > Looking a bit deeper I discovered that each time NM disconnects from a > > > > > > networks it sets random ssid/essid to the card (using wireless > > > > > > extensions) > > > > > > > > > > This forces a scan > > > > > > > > > > > After that scan fails for some time. > > > > > > > > > > > > as a NM free example you can run > > > > > > > > > > > > iwconfig wlan0 essid dummy > > > > > > iwlist scan > > > > > > > > > > and then this fails with EBUSY. > > > > Thanks for explanation. > > > > Since NM has its reasons to clear essid (to prevent unwanted > > > > association), then what can be done to prevent this (and still use > > > > wireless extensions, since nl80211 support isn't yet mature)? > > > > > > Nothing. Wext sucks, news at 11, yadda. > > Thanks. > > Everything understood. > > Of course, we can go back to dropping the scan request, but that > wouldn't be very nice. > > Is this creating any problems? Yep, but dropping the request won't help ether. Problem is that wpa_supplicant will attempt to scan before association, scan fails (it doesn't know it is already running) thus it waits 10 seconds. (I patched it to wait 2 seconds). It happens if user first disconnects, and then reconnects to a network (typical test I do for time it takes to connect) Now I patched it not to clear essid on disconnect, and this helped reduce connect times by about 2 seconds. now it takes just 3~4 seconds to connect to open network, and ~6 seconds to WPA2 network. (This is with patched dhclient, I reduced its timeouts, but this is another story.... it seems that first DHCPREQUEST never succeeds, and I tested this with 2 cards, and few wireless networks) Best regards, Maxim Levitsky > > johannes -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
