Thanks for your reply, before I followed your recommended steps I did a system upgrade as recommended by ubuntu update manager. Since this also updated systemd which is AFAIK pretty basic to the system, I tested both after the upgrade AND after the switch to this mainline kernel you recommended. Behavior became much stranger with the regular system update, and in both cases (i.e. ubuntu kernel and mainline kernel) the system behaved more or less the same, as far as wlan is concerned:
- After a reboot everything looks normal, wlan comes on even before login, and stays intact after login. network manager applet in top bar shows wlan networks plus the one I am connected to. - After a sleep/wakeup, network manager shows loss of wlan connection. No existing wlan networks are shown in wireless network list. Opening "connect to hidden network" menu lists all networks I ever connected to, but will not allow me to hit connect with any of them in the list, connect button is grayed out. - Now here comes the freaky part: in SOME of these instances I am actually connected to my home wlan! This is not shown directly in network manager, only after opening connection information window one can see that there is a virbr0 device, and an active wlan0 device. After many reboots and sleep/wakeup cycles with both kernels (ubuntu and mainline), I can state that there is about a 50% likelyhood that wlan becomes active, and that if wlan is active after one sleep/wakeup cycle, chances are high that it will work in consecutive sleep/wakeup cycles. In two cases (one for each kernel) I could create a special case: wlan active after reboot, active again after sleep/wakeup, then inactive after next sleep/wakeup. Since these cases yield a very compact dmesg file, I post both of them here. I hope this helps pinning down the issue, please let me know if you need further data or tests. Cheers, Rudi ** Attachment added: "dmesg file created with regular ubuntu kernel: reboot, sleep/wakeup + working wlan, sleep/wakeup + broken wlan" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1584533/+attachment/4669692/+files/dmesg-flaky-ubuntu -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1584533 Title: Lenovo X220 unable to wlan after resume from sleep To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1584533/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
