Is fixed by this patch https://patchwork.freedesktop.org/patch/285155/ , but it
seems to have got forgotten.

@Nicholas Kazlauskas Could you try push this to 5.1?

Bug ID	109749
Summary	FreeSync stutters if framerate is less than refresh rate and vsync/flipping is on
Product	DRI
Version	DRI git
Hardware	Other
OS	All
Status	NEW
Severity	normal
Priority	medium
Component	DRM/AMDgpu
Assignee	dri-devel@lists.freedesktop.org
Reporter	bmilreu@gmail.com
CC	nicholas.kazlauskas@amd.com