My primary monitor preference does not survive reboot. I want the primary display to be on the left and apply the setting system-wide. When I log back into the system after a reboot, the primary display always reverts to the one on the right. I am using identical Acer monitors and the EVGA Nvidia GTX980Ti graphics adapter in a single-card configuration with two DisplayPort to DVI cables. The graphics card is using the repo-supplied proprietary drivers.
I experienced this problem also when I first installed Ubuntu-MATE. I also connect both monitors to two DVI ports in a single card. Only difference is my card is older (a GTX 560 Ti).
I stumbled my way out of it on what I think was:
- First changing the Window Manager from compiz to Marco(Software) in Preferences->Look and Feel->Mate Tweak
- Then by forcing the correct settings again in the Preferences->Hardware->Display
- Making sure the settings were also correct in the NVIDIA X Server Settings under System->Administration
Then followed with a reboot.
I am unsure if these steps individually or together had any effect, but I no longer experienced it. The computer started to boot normally since then, with the primary monitor correctly identified. The driver I am using is 361.42.
Marfig, thanks for the tips. The window manager was already set to Marco (software), as I had never enabled compiz in the settings. Given the power of this Nvidia card, I switched to Marco (Compton GPU compositor). I rebooted and the right monitor was primary again. At that point, I used the hardware display settings to force primary back to the left. I am also using the 361.42 driver and have verified the relative positions in Nvidia settings are what I want. What’s really weird is that the left monitor has analogous names in MATE display preferences and Nvidia settings, DP-5 and DFP-5, respectively. The right monitor is DP-3 in MATE display preferences and DFP-7 in Nvidia settings.