I'm at a loss as to how to debug this at the NetworkManager level. Nothing is truly special there; what we do is basically just detect the type of device to know whether to pass ap_scan=1 or ap_scan=2 to wpasupplicant, which is what actually establishes and keeps the connection up. Other code looks at stats for speed, range, etc. calculation, but that's hardly something that would affect speed. Then there's the obvious background scanning, but this isn't causing any issue on other cards.
As a test, could you please try to run Precise with the latest NetworkManager from the NetworkManager trunk ppa (http://launchpad.net /~network-manager/+archive/trunk). There's been some changes to the wifi code in git, so it's worth verifying. As for another test; please try to run just wpasupplicant from Oneiric on Natty, and see if this causes the connection to not get the expected performance. >From there, we'll need full syslog of what happens while testing the >connection performance, preferably with NetworkManager in debug: you can get >this easily after starting NetworkManager but using the debug helper script >here: http://cgit.freedesktop.org/NetworkManager/NetworkManager/plain/test/debug-helper.py Call it as "debug-helper.py --nm debug"; we want to get all the debugging information available. If nothing helps, packet captures when experiencing the problem would certainly shed more light on what's happening. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to network-manager in Ubuntu. https://bugs.launchpad.net/bugs/836250 Title: [Oneiric] [Regression] Intel Corporation Centrino Ultimate-N 6300 poor networking, packet loss and very slow Lenovo X201 and T500 laptops Status in The Linux Kernel: In Progress Status in “linux” package in Ubuntu: Triaged Status in “network-manager” package in Ubuntu: Confirmed Status in “linux” source package in Oneiric: Triaged Status in “network-manager” source package in Oneiric: Confirmed Status in “linux” source package in Precise: Triaged Status in “network-manager” source package in Precise: Confirmed Bug description: This may be either network-manager or kernel, depending on triage... I have verified this on both a Lenovo X201 and a Lenovo T500 laptop. Both work perfectly with fully updated 10.10 and 11.04 versions of Ubuntu. However, booting into a fully updated 11.10 (as of 28/08/11) I get very poor wireless networking performance. Between 6-10% packet loss, very very slow connection and transfer rate. All in all, practically unusable. I have reported the bug on the X201 laptop, I will add the similar logs from the T500 also if required. As soon as I swap back to either 10.10 or 11.04 I get perfect wireless, it's only on 11.10 that I get problems, this would suggest it's not hardware or configuration on my side. I have had this since first installing 11.10 which was a little after Alpha 2. Wired connection is fine. ProblemType: Bug DistroRelease: Ubuntu 11.10 Package: network-manager 0.9.0-0ubuntu1 ProcVersionSignature: Ubuntu 3.0.0-9.14-generic 3.0.3 Uname: Linux 3.0.0-9-generic x86_64 Architecture: amd64 CRDA: Error: [Errno 2] No such file or directory Date: Sun Aug 28 21:26:05 2011 EcryptfsInUse: Yes Gconf: IfupdownConfig: auto lo iface lo inet loopback InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Alpha amd64 (20110803.1) IpRoute: default via 192.168.100.1 dev eth0 proto static 192.168.100.0/24 dev eth0 proto kernel scope link src 192.168.100.41 Keyfiles: Error: [Errno 2] No such file or directory NetworkManager.state: [main] NetworkingEnabled=true WirelessEnabled=true WWANEnabled=true WimaxEnabled=true ProcEnviron: LANGUAGE=en_GB:en PATH=(custom, user) LANG=en_GB.UTF-8 SHELL=/bin/bash SourcePackage: network-manager UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/836250/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
