greeter does not use active display

[ttosttos]

When using an external display, logging out activates built-in (disabled) display to show greeter. Once credentials are entered, Pantheon session starts on the external display as expected. Greeter seems to have display choice hard coded.

[Fabian Thoma (fabianthoma)]

Actually I'd like to argue that this is a feature. The Greeter does mirror onto any display, no matter how they might be setup by the user. This should also not be a security issue or an issue whatsoever because all critical information (passwords) are redacted even on entering them.
So I'd actually support this not being changed to a user setting (which could also be different for each user here) and rather leave this like it currently is.

[Danielle Foré (danrabbit)]

Since this issue seems to need more thought and the implementation would be kind of involved, I'm inclined to bump this to the next release.

[Cassidy James Blaede (cassidyjames)]

I can't confirm this bug with greeter in Loki; it now mirrors to all displays as intended.

[Cassidy James Blaede (cassidyjames)]

Ah, never mind, after re-reading this bug and the duplicates of it, I better understand the issue. The bug is that Greeter does not know which display is the "primary" display and instead (as of Loki) shows on all displays.

Mirroring to all displays is not the worst, but we should detect the Primary display, then set the resolution of the mirroring to be based on the Primary display if possible so it looks the best on that display (but still usable on the other displays)