Comment # 16 on bug 1054645 from rens groenewegen

tested with option --left-of, as stefan suggested.

starting point: 3 monitors.
+---------+------------+
| hdmi-1  |   hdmi-2   | 1920x1080 (both)
|         |            |
+---------+------------+
|         | 2560x1440
|  edp-1  | 
+_________+

xrandr --output HDMI-1 --scale 0.8x0.8 --left-of HDMI-2  
X Error of failed request:  BadMatch (invalid parameter attributes)
  Major opcode of failed request:  140 (RANDR)
  Minor opcode of failed request:  7 (RRSetScreenSize)
  Serial number of failed request:  37
  Current serial number in output stream:  39
4.4.120-45-default:itsme:[/data/itsme]
= xrandr |grep -e Screen -e connected
Screen 0: minimum 320 x 200, current 3856 x 1944, maximum 8192 x 8192
eDP-1 connected 1536x864+0+1080 (normal left inverted right x axis y axis)
294mm x 165mm
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-1 connected primary 1536x864+384+0 (normal left inverted right x axis y
axis) 527mm x 296mm
HDMI-2 connected 1920x1080+1920+0 (normal left inverted right x axis y axis)
527mm x 296mm


screen buffer is wrong: should be 3456x1944  ( 1536 + 1920 )x 1944

output HDMI-2 should be at 1536x0, which it is not. it's at it's old position.

so much for what xrandr says.
the FB operation fails, but the placement succeeds, although X has lost track
of 
the reality "on the ground".
check out the attachment with the screenshot (taken with a camera, not with X
:-) ) of this text, on the gap between HDMI-1 and 2:
there is no gap.
while there should have been a 384 pixel gap.

as we can see, the word "have" in the previous sentence is not missing a single
digit, not quite possible when 384 pixel should have been missing....