Impossible to add secondary display to the left of primary

[Christoph Buchner]

I got two identical monitors, the primary (DFP-0) in front of my keyboard, and the secondary (CRT-0) to the left due to space constraints.
Now, despite that this option is given by disper, it seems impossible to have my primary monitor (with the unity leftbar, and default monitor where applications start) in front of me (as in single mode), and extend to the _left_ side with my secondary display CRT-0.
I tried all combinations of
disper -d DFP-0,CRT-0 -t left -e
disper -d DFP-0,CRT-0 -t right -e
disper -d CRT-0,DFP-0 -t left -e
disper -d CRT-0,DFP-0 -t right -e

Ultimately I would want to do this with disper-indicator, but first things first - it seems that the order of the displays in the -d argument is not respected with regard to the -t argument, -d CRT-0,DFP-0 -t left and -d DFP-0,CRT-0 -t right give the same result.

To clarify my use case, I would like to use my primary/right monitor for day-to-day work (due to workplace ergonomics), using the secondary monitor on my left primarily for displaying manual pdf files and the like...

[wvengen (wvengen)]

Hi, thanks for your bug report, this doesn't look good. Disper always sets the origin to the most left screen as to avoid negative coordinates. I remember that there were problems with this (though I can't remember exactly what they were). This is where I think the Xinerama info order should help (see `xdpyinfo -ext XINERAMA`). It might just be that Unity doesn't handle multi-head well. Or it's related to bug #782087. You could try the patch attached there.

[Christoph Buchner (bilderbuchi)]

OK, after disper -d DFP-0,CRT-0 -t left -e, this gives http://pastebin.com/EnxcyZQR
Most interesting bit probably at the end:
XINERAMA version 1.1 opcode: 151
  head #0: 1400x1050 @ 1400,0
  head #1: 1400x1050 @ 0,0
Here the "effective primary"(i.e. with launcher etc) screen is the left one (CRT-0), although the command says DFP-0 should be the primary.

Seems unity is full of multi monitor bugs. apparently someone has my problem, but just the other way round - it's considered a but if the launcher stays on the primary monitor! bug #742544
I would have tried that bug's comment #4, but I don't have a monitor.xml on my system. :-(

[wvengen (wvengen)]

Probably not a bug in disper, it seems like Unity does not honour XINERAMA's screen order.

[Jason Smith (jassmith)]

Unity will be always place the launcher on the left most screen for the Oneric release and primary monitor wont be a concern.

[Christoph Buchner (bilderbuchi)]

So yout comment implies that this could change in Oneiric+1, why not mark/milestone it as such? And by "won't be a concern" do you mean "will be ignored by unity"?