Installing OpenSUSE on Thinkpad P50
The Lenovo Thinkpad P50 is quite a nifty laptop. However installing Linux required some digging around, so I'm writing this up for others to stumble upon it when looking for answers to similar issues.
It is very important to change the BIOS/UEFI setting from "Legacy and then UEFI" to "UEFI only". Otherwise, installing Linux from a USB key boots in Legacy mode, and after 2 hours of installation, the OpenSUSE installer finishes with the very imprecise "an error occured during boot loader installation". After reading http://www.rodsbooks.com/linux-uefi/ I changed the setting to UEFI only, re-did the installation, and voilà, the bootloader installs just fine. Compatibility is sometimes more trouble than not :-)
Hardware consideration: since it uses a M.2 SSD (small form factor) and doesn't provide the necessary (Lenovo-specific?) cable to plug a 2.5" SSD, my initial idea of replacing the SSD with a bigger one failed. Should have bought another M.2 SSD instead.
Grub2 in graphical mode was horribly slow (maybe due to high DPI, too many pixels to paint?). I changed /etc/default/grub to say GRUB_TERMINAL=console, and then ran
grub2-mkconfig -o /boot/grub2/grub.cfgand
grub2-install. Good old menu in text mode, much faster.
The Wifi didn't work at all, because OpenSuSE Leap 42.1 includes kernel 4.1.12, but proper support for "Intel 8260" with subsystem 0130 (see lspci -vv) was only added in kernel 4.2 (see http://askubuntu.com/questions/693109/intel-wireless-8260-unclaimed-network for the one-liner change to the kernel sources, but I didn't feel like recompiling the kernel...). So I switched to OpenSuSE Tumbleweed which has kernel 4.5. Magic, the wifi works now.
Remaining issue: when asking for an encrypted LVM group, the installer didn't create an unencrypted /boot partition; it still boots fine but I have to enter the crypto password twice (once for GRUB itself, and once for booting linux). I wonder why grub can't just pass along the now-unencrypted device or something, dunno how that works exactly. Makes me wonder if there isn't a way to give grub everything it needs in the small EFI FAT partition...
Now moving on to compiling my own Qt5, KF5, Plasma5 :-)