As far as I can tell this laptop is readily compatible with ubuntu 16LTS but installing ubunutu 14.04 on the dell xps 15 and getting in to function correctly takes time. Having said that,
I really like this laptop I'm really trying to like this laptop because its powerful, light and a battery life well over 6 hours. Anecdotally other people have also complained to me about the dell xps mainly about hardware issues.
I installed ubuntu 14.04 alongside windows 10 using a bootable live USB
Firstly we need to disable fast booting and hibernate in windows 10 (we also need to do this to shrink the volume to create free space for the install)
Disable secure boot from the BIOS
Choose to boot from USB using UEFI i.e. not legacy mode, again in the BIOS options
Once ubuntu has booted it it should recognize the other operating systems present, if it doesn't there is something wrong, probably you're booting in legacy mode
Afterwards it should be OK to install in the normal fashion.
I then tried to install ubuntu 16.04 alongside both ubuntu 14.04 and windows 10, I shrank the volume in windows 10, then created a live usb, during the boot F12 enters the menu and you need to select boot from USB under the UEFI menu
However, this just stayed on the splash screen with no error messages, the problem is the nvidia drivers. This can be resolved by adding nomodeset, during the boot menu press 'e' while try ubunut is selected. Then add 'nomodeset' to the linux line just before '---' and after splash. Something similiar is presented here
Finally, Ubuntu won't shut down correctly just froze. After trawling through stack the following worked ( I can't find the original link)
Afterwards, it will still freeze unless you use the nvidia drivers, System Setteings->Software & Updates->Additional Drivers
sudo nano /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quite splash acpi_rev_override=1"
2. Graphics card
Using NVIDIA 381.22 did not work for me, bascially no gui was loaded at all
The previous version of NVIDIA (378 ?) worked well except when I connected via HDMI to an external monitor, then I had very poor graphics and lots of freezing. I think the issue is that NVIDIA controls the external screen whereas INTEL run the built in display. Apparently this is physically wired but there is a config file to edit as a work around.
Currently I'm using the X.Org driver that's working great including with the external screen. There are occasional graphics glitches, notably with matlab but nothing I can't live with.
3. Ethernet & Wifi
Wifi card is Qualcomm Atheros QCA6174 802.11ac Wireless Network Adapter, I had absolutely no luck in getting this to work. Eventually I bought a Panda 300Mbps Wireless N USB Adapter.
Laptop doesn't have a dedicated Ethernet port, I am using USB Network Adapter, Rankie SuperSpeed USB 3.0 to RJ45 Gigabit Ethernet Network Adapter - R1161,
However my etherent connection was unbearably slow even causing the computer to freeze up every so often. For example any sudo command took about 30 seconds to be executed, opening a folder in nautilus also caused an unresponsive screen. The process ,wpa_supplicant, was using as much as 90% of the CPU. I tried a lot of things to resolve this inculding fiddling with my interent settings and disabling IPvS 6 but no luck. Eventually I completely purged (sudo apt-get purge network-manager) network manager and installed wicd (do this first) which resolved the issue.
This was also causing problems with licenses, since the host ID was changing, essentially I needed two licenses one for wifi and another for ethernet.
Wicd is working an order of magnitude better than network manager, these instructions are useful for connecting to company/univeristy secured wifi.
Happily Wifi works in 16.04 out of the box
4. Audio Problems
Occasionnally, when plugging unplugging headset, the headphones no longer work, try installing this program and manually turning on and off the headset pin
Sometimes the sound completely goes, in that case, if the above doesn't work. Disable the audio in the bios and boot normally. Afterwards re-enable the audio and it should be OK
sudo apt-get install alsa-tools-gui
5. Other Problems
Sometimes ibus-daemon process causes the computer to free just need to kill it to get back to normal
I use gurobi a licensed optimization software where the license is based on the host id. Previously I had issues when switching from wifi to ethernet, my hostid would change and license would fail. Then there were other cases where my hostid would change seemingly randomly. Eventually, I found out my hostid changes because I was charging my phone off a usb port. I'm guessing this is not meant to happen...