Dual TB displays on a late 2013 Mac Pro — Reverse numbering

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Level 2

460 points

Dual TB displays on a late 2013 Mac Pro — Reverse numbering

I don't know if this is going to cause a problem later on but it bothers me that System Preferences> Displays is numbering my primary TB display on the left as #2 and the secondary one on the right as #1. Everything I have tried has given the same result — no change to the condition.

Things tried:

Direct cabling from the back of the Mac Pro to the two displays with various arrangements, different ports;

Daisy chaining one display off the other;

Booting with only the primary display connected then shutting down, adding the second;

Used System Preferences> Displays to switch display configuration and menubar placement.

I suppose the real question is: How can I change the primary display's number to #1 and the secondary's to #2?

And the final question: Does this System Preferences> Displays numbering matter and does it affect Mission Control and Spaces?

Mac Pro (Late 2013), OS X Mavericks (10.9.2), And lots of other Macs and PCs

Posted on Feb 28, 2014 4:17 PM

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Answer 1

Feb 28, 2014 5:48 PM in response to Pedro

Does this System Preferences> Displays numbering matter and does it affect Mission Control and Spaces?

No.

Everything you care about can be arbitrarily re-assigned. There are no "special places" or lowest-numbered display preferences. The Primary display (but not necessarily number 1) is the one to which you have dragged the tiny MenuBar Icon is the Arrange pane.

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Answer 2

Pedro Author

Level 2

460 points

Mar 2, 2014 1:17 PM in response to Grant Bennet-Alder

The OCD in my personality drove me to seek a solution. In the end a compromise was accepted.

The display which carries in SysPrefs> Displays the status of ALWAYS being #1 is a display which had previously been used on another Mac. This appears to have set a state in the display that the display now remembers as always #1. Nothing we did with different cable arrangements or positional changes of screen and Menubar location in SysPrefs> Displays> Arrange changed this display's adherence to its designation as #1. With this one always displaying #1, the additional display could never be #1 and so took the designation #2. I remain befuddled as to why the older display always insists on being #1 — the only answer seems to be that this display has recorded this status in a ROM somwhere.

The workaround has been the physical moving of #1 display to the primary display location on the desk.

It occurred to me just now that there still remains one test to try: set up the displays as desired and then conduct a PRAM/vram reset.

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Answer 3

Mar 2, 2014 2:52 PM in response to Pedro

the only answer seems to be that this display has recorded this status in a ROM somwhere.

Maybe the numbering is based on the display's serial number. The oldest display would then always be #1.

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Answer 4

turbostar

Level 4

2,941 points

Mar 2, 2014 3:12 PM in response to Pedro

This is what I needed to do before to "reassign" a montior to be the main one. I never checked the display #s.

shut down PC, leave only primary monitor connected

PRAM reset and login

shut down then turn on

shut down again

connected remaining monitors

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Answer 5

The hatter

Level 9

60,980 points

Mar 2, 2014 3:44 PM in response to turbostar

NVRAM holds an entry for devices, and zap PRAM from cold start also clears NVRAM, so a reset from warm restart will not act the same in case someone did.

At least back with G5's and earlier with Open Firmware there were problems with devices being "remembered" even after they are removed, or a new device not showing up until OF was reset.

SMC Reset is probably the best to insure a device that stopped showing up in System Profiler to "get it back."

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