I'm experiencing the same issue on my Thinkpad X1 (gen 4) model with sid.
Switching to 2 external monitors started not working correctly in the
sense that
the one monitor that was rotated (--rotate left) did not work (blank
screen).
The one that was positioned normally worked fine.
I could also switch back to the laptop's monitor but when I put the laptop
to sleep and later woke it up it's monitor did not turn on.
These seem to possibly unrelated issues, I don't know.
The sleep issue is related to the kernel version 4.16.0-2 and the intel
i915 driver.
Downgrading to version 4.15.0-3 solved this issue.
The issue with the rotated monitor seems directly related to this. And I
followed the
suggestion above about pinning "xserver-*" but I had to add the
following pins as well so it
didn't remove gnome:
$ cat /etc/apt/preferences.d/xrandr-xserver-issues
Package: xserver-*
Pin: origin "snapshot.debian.org"
Pin-Priority: 2001
Package: gnome
Pin: origin "snapshot.debian.org"
Pin-Priority: 2001
Package: gnome-*
Pin: origin "snapshot.debian.org"
Pin-Priority: 2001
Package: gdm3
Pin: origin "snapshot.debian.org"
Pin-Priority: 2001
Package: task-gnome-desktop
Pin: origin "snapshot.debian.org"
Pin-Priority: 2001
Package: xwayland
Pin: origin "snapshot.debian.org"
Pin-Priority: 2001
The snapshot used is this one (differs from the one above):
# Snapshot
deb [check-valid-until=no]
http://snapshot.debian.org/archive/debian/20180117T154752Z/ sid main
The version of xserver-common is 2:1.19.5-1 and xserver-xorg-video-intel
2:2.99.917+git20171229-1.
Here's the relevant output of the graphics card used:
~ lspci -v | grep i915 -A 10 -B 10
00:02.0 VGA compatible controller: Intel Corporation HD Graphics 520
(rev 07) (prog-if 00 [VGA controller])
Subsystem: Lenovo Skylake GT2 [HD Graphics 520]
Flags: bus master, fast devsel, latency 0, IRQ 130
Memory at f0000000 (64-bit, non-prefetchable) [size=16M]
Memory at e0000000 (64-bit, prefetchable) [size=256M]
I/O ports at e000 [size=64]
[virtual] Expansion ROM at 000c0000 [disabled] [size=128K]
Capabilities: <access denied>
Kernel driver in use: i915
Kernel modules: i915