On my brand new Lenovo P50 the wifi is unstable. sometimes it connects, sometimes it does not, or just stops working. Sometimes wifi networks are shown in the network manager, sometimes not. Sometimes even the wifi symbol disappears and changes to the symbol with the two arrows, even when no ethernet cable is connected.
sudo service network-manager restart
solves the problem for a while, but it comes back.
Hardware is Lenovo P50,
wifi adapter intel 8260 rev 3a
Ubuntu 16.04 with all updates installed as of today
Kernel 4.4.0-28-generic
driver is iwlwifi driverversion=4.4.0-28-generic firmware=16.242414.0
sudo lshw -C network
gives
*-network
Beschreibung: Kabellose Verbindung
Produkt: Wireless 8260
Hersteller: Intel Corporation
Physische ID: 0
Bus-Informationen: pci@0000:04:00.0
Logischer Name: wlp4s0
Version: 3a
Seriennummer: 44:85:00:df:1f:b5
Breite: 64 bits
Takt: 33MHz
Fähigkeiten: pm msi pciexpress bus_master cap_list ethernet physical wireless
Konfiguration: broadcast=yes driver=iwlwifi driverversion=4.4.0-28-generic firmware=16.242414.0 ip=192.168.1.39 latency=0 link=yes multicast=yes wireless=IEEE 802.11abgn
Ressourcen: irq:133 memory:c4c00000-c4c01fff
*-network
Beschreibung: Ethernet interface
Produkt: Ethernet Connection (2) I219-V
Hersteller: Intel Corporation
Physische ID: 1f.6
Bus-Informationen: pci@0000:00:1f.6
Logischer Name: enp0s31f6
Version: 31
Seriennummer: 50:7b:9d:fe:e7:83
Kapazität: 1Gbit/s
Breite: 32 bits
Takt: 33MHz
Fähigkeiten: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
Konfiguration: autonegotiation=on broadcast=yes driver=e1000e driverversion=3.2.6-k firmware=0.8-3 latency=0 link=no multicast=yes port=twisted pair
Ressourcen: irq:130 memory:c5700000-c571ffff