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#1 2020-11-19 03:18:22

Registered: 2020-09-05
Posts: 14

Missing Resolutions and Refresh Rates on UWQHD External Monitor.

New monitor, and some new problems.

3440x1440 (21:9) is missing. Makes sense if my HDMI port were <2.0, that ratio is unavailable for all selectable resolutions.

Gnome Display settings automatically selects 3840x2160 (16:9), highest available.

Selecting 1920x1080i (16:9) over HDMI allows 120Hz with no issues.

Interestingly enough, a USB-C to HDMI adapter can do just as much, but 3440x1440 (21:9) appears (with no option to select refresh rate). Feels noticeably smoother, which means it's at least 60Hz. A bug in Gnome causes the check mark when selecting a resolution to appear next to an incorrect option (e.g. selecting 3440x1440 (21:9) marks 1720x1440).

Running Gnome 3.38.1 + GDM 3.38.2 (Wayland) w/ kernel 5.9.8

Monitor specs sheet:

Brand: Acer, model# EI342CKR
Resolution: 3440x1440 UW - QHD
Panel Type: VA
AMD Radeon FreeSync Premium Pro
Refresh Rate: 144Hz
Response Time: 1ms VRB
Brightness: 400 nits
Screen Type: Curved
Screen Size: 34 in.
2x HDMI 2.0
2x DisplayPort 1.4

inxi output:

  Info: Quad Core model: Intel Core i7-8650U bits: 64 type: MT MCP 
  L2 cache: 8192 KiB 
  Speed: 699 MHz min/max: 400/4200 MHz Core speeds (MHz): 1: 774 2: 800 
  3: 774 4: 796 5: 800 6: 790 7: 800 8: 800 

  Device-1: Intel UHD Graphics 620 driver: i915 v: kernel 
  Device-2: NVIDIA GP108M [GeForce MX150] driver: N/A --> (Disabled on boot)
  Display: wayland server: 1.20.9 driver: N/A 

No idea what the HDMI spec is, but it's DP capable over thunderbolt.

Another thing, offtopic: what is a reliable source for some cool wallpapers? Never had wallpapers, not a bad time to start.


#2 2020-11-22 20:44:05

Registered: 2020-09-05
Posts: 14

Re: Missing Resolutions and Refresh Rates on UWQHD External Monitor.

What's the point of being detailed, reporting potential bugs if no one ever responds? Bummer.


#3 2020-11-23 12:26:59

From: Netherlands, Europe
Registered: 2005-10-04
Posts: 9,592

Re: Missing Resolutions and Refresh Rates on UWQHD External Monitor.

Personally I've never used gnome longer then about 2 hours, never owned an nvidia card and don't have any need for wayland.
In other words, I lack knowledge/experience to thoroughly troubleshoot the issue.

Usually I don't reply in such cases hoping someone better qualified will.
Since no one did, I'll try to get things started using generic troubleshooting methods.

Inxi gives high level info abstracted from raw data.Many archlinux forum users (including me) prefer the raw data.


$ lspci -k

Using wrong cabling is a common problem cause with HDMI .
For HDMI 2 you need a Premium High Speed HDMI Cable, a Premium High Speed HDMI Cable with Ethernet or an  Ultra High Speed HDMI Cable [1]
Does the cable you use match with that ?

Do things work better if you use a display port cable ?

There are 3 components that need to be verified to determine if they're part of the problem

start gnome on wayland from console

start sway or kde plasma on wayland

start X from console with a minimal setup
post xorg log and xrandr -q output


Disliking systemd intensely, but not satisfied with alternatives so focusing on taming systemd.
Did you use the guided installer ? If yes, I can't help you.

(A works at time B)  && (time C > time B ) ≠  (A works at time C)


#4 2021-04-19 08:54:21

From: Sydney
Registered: 2018-01-06
Posts: 1

Re: Missing Resolutions and Refresh Rates on UWQHD External Monitor.

Hey cemi, did you have any luck?

I'm having similar problems but in my case I am using an i7-11700 CPU.

There are no errors reported in any log file.

After trial and error I came to the conclusion that the kernel disqualified a bunch of high resolution modes incorrectly (ie. assuming the IGFX would be unable to drive modes higher than 2560x1440 in my case, when I know the chip can push 2k and beyond).


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