xf86-video-nouveau missing settings in kms.conf
While i was setting up my system with nouveau i ran into
<code class="text"> Xorg fails to start with "(EE) [drm] failed to open device" </code>
it turns out i had to explicitly enable the following settings:
<code class="text"> /etc/modprobe.d/kms.conf drm modeset=1 nouveau modeset=1 </code>
this file already contains these settings for radeon and i915, but nouveau depends on it too.
(from redmine: issue id 8775, created on 2018-04-07)