https://bugs.freedesktop.org/show_bug.cgi?id=93615
--- Comment #3 from EoD EoD@xmw.de --- I tried standby again by accident and it seems to work just fine now.
I am using drm-next on commit d8e0cae645504a787b05abfb91afee8cd7fa1701, kernel 4.4.0-rc6-gd8e0cae.
Did my change some stuff on my bios by accident (IOMMU?) or did you fix it in the recent kernel?