Comment # 7 on bug 104142 from Mike Lothian

I'm running agd5f's drm-next-4.17-wip branch with
https://patchwork.freedesktop.org/series/38985/ applied on top along with
https://github.com/FireBurn/KernelStuff/blob/master/05-remove-warn.patch
removing the WARN_ON(adev->dm.cached_state);

I've reverted the removal of the WARN_ON and it seems to be fixed thanks