[SOLVED] Dual monitor woes Mint 19.2

lpallard · 08-09-2019, 04:59 PM

I have installed Mint 19.2 on my desktop which has both a Samsung 24in monitor as well as a new LG UHWQ 34in monitor which are setup in Mint as continuous display (side by side).

Every time I wake up the computer (or cold boot it), if one monitor is turned off or not on the proper input, Mint thinks the monitor is unplugged and proceeds to reconfigure my desktop as duplicate.

This literally happens every time. I have to go to Display and uncheck "MIrror displays" then drag the smaller monitor to the proper side, and click apply.

Not a huge task but I cannot force Mint to save the config and stick to it.

Anybody has seen this before? I cannot recall if the previous Mint releasee did that but I sure can tell you windows 10 no matter how much I hate it doesnt do that at all.

mrmazda · 08-11-2019, 08:13 AM

These are merely things to try:

Don't power down the displays. When in sleep mode, the electricity they use is virtually zero.
Switch cables between the two displays, so that the other naturally becomes the primary.
Ctrl-Alt-F4 prior to allowing sleep mode, Alt-F7 when time to return to X.
log out, log in on a vtty, delete all saved display configuration settings
Use a different configuration tool:
- arandr (gui tool)
- xrandr (in a startup script)
- /etc/X11/xorg.conf

When I start a Cinnamon session, the displays just naturally go side by side as extended desktop.

Code:

# xrandr | egrep 'onnect|creen|\*' | grep -v disconn | sort -r
Screen 0: minimum 320 x 200, current 4480 x 1440, maximum 8192 x 8192
HDMI-3 connected 1920x1200+2560+0 (normal left inverted right x axis y axis) 519mm x 324mm
DP-1 connected primary 2560x1440+0+0 (normal left inverted right x axis y axis) 598mm x 336mm
   2560x1440     59.95*+  74.92
   1920x1200     59.95*+
# inxi -GxxS
System:    Host: ab250 Kernel: 4.15.0-54-generic x86_64 bits: 64 compiler: gcc v: 7.4.0 Desktop: Cinnamon 4.2.3
           wm: muffin dm: LightDM Distro: Linux Mint 19.2 Tina base: Ubuntu 18.04 bionic
Graphics:  Device-1: Intel HD Graphics 630 vendor: ASUSTeK driver: i915 v: kernel bus ID: 00:02.0 chip ID: 8086:5912
           Display: x11 server: X.Org 1.19.6 driver: modesetting unloaded: fbdev,vesa
           resolution: 2560x1440~60Hz, 1920x1200~60Hz
           OpenGL: renderer: Mesa DRI Intel HD Graphics 630 (Kaby Lake GT2) v: 4.5 Mesa 19.0.2 compat-v: 3.0
           direct render: Yes

ondoho · 08-11-2019, 08:43 AM

IMO, this is the correct behaviour when the monitor is switched off when you start the machine.
You could write a small script that configures the monitors as you want - an xrandr oneliner - arandr can actually do that for you. Then bind that script to a hotkey that you press after you switch both monitors on.

lpallard · 08-11-2019, 11:41 AM

I mentioned "switched off" but most of the time, they are on a different input. I use both monitors for my desktop as well as for my work laptop. When I shutdown work laptop and resume the desktop, if the monitors are still on the input from the laptop, Mint does what I said.

The command you suggested gave:

Code:

Screen 0: minimum 8 x 8, current 5360 x 1440, maximum 32767 x 32767
HDMI-0 connected primary 3440x1440+0+0 (normal left inverted right x axis y axis) 800mm x 335mm
DVI-D-0 connected 1920x1080+3440+0 (normal left inverted right x axis y axis) 477mm x 268mm
   3440x1440     59.97*+  49.99    29.99  
   1920x1080     60.00*+  50.00

Perhaps this is because I am used to Windows behaviour in regards to dual monitors and when one of them is on a different input, Windows still assumes the desktop spans to it and you simply don't see the windows or stuff on it, but the desktop remains across monitors. Another annoyance, the LG monitor (HDMI-0) doesn't auto switch inputs.

I will fiddle with a hotkey of some sort. I am imagining pressing a keyboard combo to restore the display settings.

ondoho · 08-12-2019, 12:26 AM

^ sounds messy.
Nevertheless, mrmazda says it works for them:

Quote:

Originally Posted by mrmazda

When I start a Cinnamon session, the displays just naturally go side by side as extended desktop.

Interesting.
So trying to reproduce OP's problem, they still go side by side "automagically"?
I wonder how this is achieved under the hood - Xorg itself, or cinnamon, or something else?

mrmazda · 08-12-2019, 04:49 AM

Quote:

Originally Posted by ondoho

So trying to reproduce OP's problem, they still go side by side "automagically"?
I wonder how this is achieved under the hood - Xorg itself, or cinnamon, or something else?

Automagic happens also in IceWM, KDE3, TDE and Plasma, maybe XFCE too, which I use very rarely. Plasma always brings up a great big graphic here, apparently expecting a confirmation, or facilitating rearranging. I always X it away, not wanting Plasma to save anything to do with display settings. I do those globally through /etc/X11/*, and do a lot of PC, OS, display and output swapping.

It seems likely the Xorg server started doing this itself somewhere between v1.17.2 (openSUSE 42.1) and v1.18.3 (Debian 9). It also might be KMS between kernels 4.4 and 4.9, or a mix of kernel and server.

The GPUs I used over the past few hours to check were GeForce 8400S/GT218 (2010; DVI, HDMI & VGA), Quadro NVS 310/GF119 (2012; dual DisplayPort) using mostly modesetting DDX, 1 or 2 using nouveau DDX, and X4500 Intel using modesetting DDX.

lpallard · 10-07-2019, 08:39 PM

Replying because I have not found a quick workaround yet. Yes this is UBER messy. I just did a quick check, with both monitors ON and their inputs toward the Mint desktop, the display dialog box is the First screenshot below (monitors side by side, not mirrored).

Then I simply switched the input of the LG monitor to the 2nd input (laptop), Mint reconfigured the desktop on the Samsung as a single display as seen on the second picture (mirrored displays).

During the day, I have to often switch between my desktop and laptop's displays by flipping the monitors inputs, and always end up re-configuring the displays in Mint while Windows 10 keeps going and going (this is about the only time I will give windows the thumbs up).. This happens 10 times a day.

I may be misunderstanding how all that stuff works, but this looks like Mint sees the monitor input switch as if the monitor was unplugged... To avoid this issue, when in Windows, I need to ensure that:

1. The desktop is either in sleep mode or OFF
2. I flip both monitors input to the proper inputs (to the Mint desktop)
3. Power on or wake up the Mint desktop

Otherwise, off to the display config.