Install the recently released stable Kernel 4.3 from Ubuntu mainline kernel repository, that solved wlan for me. However, Bluetooth has issues now with stereo playback. A2DP is selectable, but playback remains mono. I am still investigating whether this is another marvell issue (since the marvell card on the Surface Pro is a combined WLAN and Bluetooth device).
Install the recently released stable Kernel 4.3 from Ubuntu mainline kernel repository, that solved wlan for me. However, Bluetooth has issues now with stereo playback. A2DP is selectable, but playback remains mono. I am still investigating whether this is another marvell issue (since the marvell card on the Surface Pro is a combined WLAN and Bluetooth device).