Separate X-Screen Crashes Cinnamon

[Jeremy Jao]

- Linux Mint 17 Cinnamon
- Nvidia Quadro K2200
- Drivers: xorg-peppers ppa nvidia-140
- ASUS P287Q (DP 1.2) - main
- Lenovo ThinkVision 1600x1200 (DVI)

I would go sudo into nvidia-settings and tell the nvidia settings to make the Lenovo be a separate X-Screen. To apply the settings, I have to restart the whole computer.

What happens when I do that, the 2nd monitor doesn't work at all, the main monitor will have a weird stripe at the top (grey with washed-out words) and will say that Cinnamon has crashed. I have to fix it by going to the command line and tell nvidia-settings to change my Lenovo monitor back to X0. Ubuntu 14.04 doesn't crash... it has a bug where the 2nd x-screen just has a completely blank screen but my mouse is able to access it with an X as the cursor.

I would expect two separate desktops on two separate screens.

This will always happen.

[Jarl Gullberg (jarl-gullberg)]

I'm affected by this bug as well.

Enabling multiple X screens when running cinnamon causes it to crash immediately on login, dropping to fallback mode. A reset of the Xorg.conf file is usually required to bring it back, but occasionally just removing the multiple X screens works.

Steps to reproduce on my system:
1. Install the proprietary nvidia drivers.
2. Open nvidia-settings.
3. Go to X Server Display Configuration
4. Set any number of screens to use separate X screens.
5. Apply the configuration by saving to X configuration file.

Cinnamon should now crash. If not, relog and Cinnamon will crash.

System information:
Nvidia proprietary drivers, version 361.28-0ubuntu1~gpu14.04.1.
Linux Mint 17.3 "Rosa" Cinnamon
Cinnamon 2.8.6
Linux Kernel v4.2.0-25-generic

[Joakim Nilsson (joankim)]

I made an account just to comment here.

Nvidia requires GPU's to be assigned to an Xserver for it to be possible to manually control clocks, voltage and fan speed. This is done in nvidia-settings after adding the "Coolbits" option to the xorg.conf file, and adding the device to an Xscreen.

This bug therefore makes it impossible to use these options together with Cinnamon. (that's not in fallback mode)

I've linked/attached my current xorg.conf file, the xorg log and the xsession error log. (/etc/X11/xorg.conf, /var/log/Xorg.0.log, ~/.xsession-errors)

I've spent hours tring to figure this out, and tried all possible combinations in my xorg.log file. I will happily provide more information or testing if anyone is willing to help out with this.

System:
- 1x Nvidia GTX 1080
- 2x Nvidia GTX 780
- Nvidia driver 370.28 from nvidia.com
- Linux Mint 18
- Cinnamon 3.0.7

xorg.conf: http://pastebin.com/PcrXLq9z
Xorg.0.log: http://pastebin.com/vnEEwZ9z
.xsession-errors: See attachement

[Joakim Nilsson (joankim)]

I'd like to add that this exact bug on mutter has been discussed heavily here: https://bugzilla.gnome.org/show_bug.cgi?id=648156

Making the display manager ignore any additional X-screens has been proposed as a simpler solution compared to adding the functionality for multiple X-screens.