[SOLVED] Two Full HD monitors in Mint 18.3 / maximum screen resolution

Screen resolution, 3D Acceleration, nVidia, ATI
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fnick
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[SOLVED] Two Full HD monitors in Mint 18.3 / maximum screen resolution

Post by fnick » Sun May 13, 2018 8:04 am

Hello community!
I'm trying to set up my Mint 18.3, which runs on my HP EliteBook 8460p notebook, to use two external monitors. My notebook is connected to a docking station / port replicator that has three video ports: 1x VGA, 1x DisplayPort 1x DVI. The notebook itself has 1x VGA and 1x DisplayPort.
The two monitors are BenQ GL2450.

The assignment of the ports to monitors is as follows:
  • HDMI1 -> DisplayPort of the docking station -> monitor 1
  • HDMI2 -> DVI-Port of the docking station -> monitor 2
  • HDMI3 -> DisplayPort of the notebook -> not in use
When I try to set the resolution of the second display to 1920x1080, the window manager stops reacting to mouse clicks. In the meantime the counter is running in the background and the system awaits confirmation of the settings by a click which I can't execute since none of the windows is responding. After the countdown, the system tries to restore the settings to previous values, which it fails to do properly and the windows remain non-responding. I then only can regain access by restarting the DM by pressing CTRL + ALT + BACKSPACE.
The system does support two simultaneously connected monitors, but their horizontal resolution has to be <= 3200 px (see the output below), so the first monitor can be used in the FHD mode with 1920x1080 px, but the second has to with 1280x720 px (1920 px + 1280 px = 3400 px).

When I open the Display-Tool I see following:
https://preview.ibb.co/mgaSty/Display_Tool.png

Here is the output of the ARandR, when the configuration is 1920 x 1080 + 1280 x 720:
https://image.ibb.co/gTxe6J/arandr.png

Here is the output of the ARandR, when the configuration is 1920 x 1080 + 1920 x 1080:
https://image.ibb.co/ebHe6J/arandr_3480x1080.png
You can see the borders of the "canvas" or "virtual display" (what's the proper word for that in terms of Xorg?), which are clearly too small for two FullHD monitors.

So the questions are:
  • Is this a known bug? If yes, how to fix it / is there a workaround?
  • Is there a way to configure Xorg to automatically adapt itself to any configuration of the monitors?
Here is the output of the xrandr:

Code: Select all

$ xrandr
Screen 0: minimum 8 x 8, current 3200 x 1080, maximum 32767 x 32767
LVDS1 connected (normal left inverted right x axis y axis)
   1366x768      60.10 +  40.07  
   1360x768      59.80    59.96  
   1280x720      60.00  
   1024x768      60.00  
   1024x576      60.00  
   960x540       60.00  
   800x600       60.32    56.25  
   864x486       60.00  
   640x480       59.94  
   720x405       60.00  
   680x384       60.00  
   640x360       60.00  
DP1 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
DP3 disconnected (normal left inverted right x axis y axis)
HDMI1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 531mm x 298mm
   1920x1080     60.00*+  50.00    59.94  
   1920x1080i    60.00    50.00    59.94  
   1680x1050     59.88  
   1600x900      60.00  
   1280x1024     75.02    60.02  
   1280x800      59.91  
   1152x864      75.00  
   1280x720      60.00    50.00    59.94  
   1024x768      75.03    60.00  
   832x624       74.55  
   800x600       75.00    60.32  
   720x576       50.00  
   720x576i      50.00  
   720x480       60.00    59.94  
   720x480i      60.00    59.94  
   640x480       75.00    60.00    59.94  
   720x400       70.08  
HDMI2 connected 1280x720+1920+360 (normal left inverted right x axis y axis) 531mm x 298mm
   1920x1080     60.00 +
   1680x1050     59.88  
   1600x900      60.00  
   1280x1024     75.02    60.02  
   1280x800      59.91  
   1152x864      75.00  
   1280x720      60.00* 
   1024x768      75.03    60.00  
   832x624       74.55  
   800x600       75.00    60.32  
   640x480       75.00    59.94  
   720x400       70.08  
HDMI3 disconnected (normal left inverted right x axis y axis)
VGA1 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
Last edited by fnick on Sun May 13, 2018 3:47 pm, edited 1 time in total.

fnick
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Joined: Sun May 13, 2018 6:35 am

Re: Two Full HD monitors in Mint 18.3 / maximum screen resolution

Post by fnick » Sun May 13, 2018 8:52 am

Okay, I've just solved it. :D
Sometimes the solution lies right before you.
Cinnamon freezes when changing resolution (Intel GPU)

If your Intel GPU is recent enough (2007 or newer) it is recommended to remove the legacy Intel driver "xserver-xorg-video-intel" and to use the built-in modesetting driver instead:

Code: Select all

apt remove xserver-xorg-video-intel
sudo reboot
Not only will the modesetting fix the freeze issue when changing resolutions, it should also work better with Cinnamon and produce better performance.

The legacy driver is no longer maintained and only useful for the old i800x and i900x family of chipsets.

If you are using one of these old chipsets or if you do not want to use the modesetting driver, an alternative is to continue to use the "xserver-xorg-video-intel" driver, but to disable VSync:

Code: Select all

echo CLUTTER_VBLANK=none >> ~/.profile
Log out for this change to take effect, and please be aware that disabling Vsync might result in video screen tearing.
Since I'm using the older graphics card

Code: Select all

$ sudo lshw -C video 
  *-display               
       description: VGA compatible controller
       product: 2nd Generation Core Processor Family Integrated Graphics Controller
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 09
       width: 64 bits
       clock: 33MHz
       capabilities: msi pm vga_controller bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:38 memory:d4000000-d43fffff memory:c0000000-cfffffff ioport:4000(size=64) memory:c0000-dffff
the solution was to

Code: Select all

echo CLUTTER_VBLANK=none >> ~/.profile
and reboot. After that I was able to set the desired screen resolution. So the problem is the graphics card and driver combination. Hope that can help someone else!

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