LG 27GP850-B not recognized

[mhutch]

I'm running mint 20.3 and my display is incorrectly being identified as "LG 32" and trying to run at 4K.

I assume the problem is that my monitor is not in the list of recognised monitors. I've manually set the resolution to 2560x1440 which is the correct native resolution. This is a 95% fix but 1) it doesn't allow the higher refresh rates supported by the monitor (up to 144Hz over HDMI), and the corrected resolution does not take effect untill after I log in. Neither of those is a huge problem, but still.

I assume I can delete the 4K resolution and add the available refresh rates via xrandr, but I also assume I will be altering the LG 32 profile. I doubt that will cause any problems for me, but would prefer to take the path of adding proper recognition of my monitor model, and maybe get that included in the repository so future users with this monitor have a more seamless experience.

Any help/advice much appreciated.

Diagnostic info below:

Code: Select all

$ inxi -SGxxx
System:
  Host: Pathos Kernel: 5.4.0-125-generic x86_64 bits: 64 compiler: gcc 
  v: 9.4.0 Desktop: Cinnamon 5.2.7 wm: muffin 5.2.1 dm: LightDM 1.30.0 
  Distro: Linux Mint 20.3 Una base: Ubuntu 20.04 focal 
Graphics:
  Device-1: Intel HD Graphics 5500 driver: i915 v: kernel bus ID: 00:02.0 
  chip ID: 8086:1616 
  Display: x11 server: X.Org 1.20.13 driver: modesetting 
  unloaded: fbdev,vesa resolution: 2560x1440~60Hz 
  OpenGL: renderer: Mesa Intel HD Graphics 5500 (BDW GT2) v: 4.6 Mesa 21.2.6 
  direct render: Yes 

Code: Select all

$ xrandr
Screen 0: minimum 320 x 200, current 2560 x 1440, maximum 16384 x 16384
HDMI-1 connected primary 2560x1440+0+0 (normal left inverted right x axis y axis) 697mm x 392mm
   3840x2160     30.00    25.00    24.00    29.97    23.98  
   2560x1440     59.95* 
   1920x1080    120.00   119.88    60.00    60.00    50.00    59.94  
   1280x720      60.00    50.00    59.94  
   1024x768      60.00  
   800x600       60.32  
   720x576       50.00  
   720x480       60.00    59.94  
   640x480       60.00    59.94  
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-2 disconnected (normal left inverted right x axis y axis)

[SMG]

I'm running mint 20.3 and my display is incorrectly being identified as "LG 32" and trying to run at 4K.

Welcome to the forum, mhutch.

Usually, the monitor not being correctly identified is because either the EDID info being passed from the monitor through the cable to the computer is not correct or it is getting corrupted.

Please give us more information on the exact model number and whether you are using an HDMI-HDMI cable and whether or not this is a new problem (i.e. did it work correctly in the past). Please also provide the output of inxi -M

[mhutch]

I am connecting via the mini HDMI port on my system.

I'm using a miniHDMI to HDMI adapter, so possible the EDID info is getting corrupted, but not the first system I've used this on. Also since it recognizes an LG monitor, have to think its getting an EDID.

First time I've connected to this monitor.

inxi -M output:

Machine:
Type: Desktop System: Intel Client Systems product: NUC5i3RYH
v: K23891-501 serial: <superuser/root required>
Mobo: Intel model: NUC5i3RYB v: K23918-501
serial: <superuser/root required> UEFI: Intel
v: RYBDWi35.86A.0386.2022.0705.1602 date: 07/05/2022

[SMG]

I doubt that will cause any problems for me, but would prefer to take the path of adding proper recognition of my monitor model, and maybe get that included in the repository so future users with this monitor have a more seamless experience.

That is a function of the hardware. LG is the one who sends the data to the monitor repository. The Linux kernel just uses the info in that repository. It does not modify the repository. I do not know how LG sets up/stores the info in the monitor so that info can get passed to through the cable to the computer.

I'm using a miniHDMI to HDMI adapter, so possible the EDID info is getting corrupted, but not the first system I've used this on. Also since it recognizes an LG monitor, have to think its getting an EDID.

Reading this again, I'm reminded of more than one LG monitor that has been problematic on Linux Mint. xrandr is usually the way to get what you want. It should be possible to also set a frequency in addition to the resolution.

You have the latest BIOS/UEFI for your computer and I would presume the cable is working properly. What people usually do is place the xrandr info in their profile so it gets loaded when they log in. There are also ways (which are more complicated) to load it sooner if you need the resolution to be correct on the login screen.

When reading xrandr output, *= current resolution and += preferred resolution. That means the system realizes the preferred resolution is not in the list.

Code: Select all

$ xrandr
Screen 0: minimum 320 x 200, current 2560 x 1440, maximum 16384 x 16384
HDMI-1 connected primary 2560x1440+0+0 (normal left inverted right x axis y axis) 697mm x 392mm
   3840x2160     30.00    25.00    24.00    29.97    23.98  
   2560x1440     59.95* 

That is usually a good sign that you can add the preferred resolution. I am not aware of a need to delete any resolutions. You would just add resolutions you want.

This topic New kernel doesn't recognize monitor SOLVED walks through how to get the preferred resolution and, once you have it, how you can add it to your .profile file. Where it mentions getting a modeline with cvt xxx yyy, you would just add a third value for the frequency.

If you have any questions about the directions, just let us know.

[mhutch]

Thank you very much for the help and insight.

[SMG]

Let us know if it works or you have any issues.

[autodctr]

Our church has about 10 LG TVs that are used as large screen monitors. Rarely have I seen any of them send the correct data to the PCs hooked up to them.