Regression: Unable to show the native 1920x1080 mode in HDMI/DisplayPort output with best refresh rates

[Jarno Suni]

My computer can not show in 1920x1080 mode with 50Hz or 60Hz refresh rate. I am using Xubuntu 20.04. In my system HDMI is just a Displayport connector with an adapter. xrandr lists the video modes of the connected HDMI monitor, and it does not show any error message or non-zero exit status when I enable 1920x1080 mode in the HDMI output; thereafter xrandr shows the mode is currently used in the HDMI output, but my monitor/TV does not show such a video mode. It can still work in 1920x1080i and lower resolution modes, or even in 1920x1080 mode with 30Hz refresh rate. VGA output works without issues.

The bug occurs with linux-image-5.15.0-67-generic but not with linux-image-5.15.0-60-generic.

Workaround in 20.04 is to use linux-generic kernel, instead.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: linux-image-5.15.0-67-generic 5.15.0-67.74~20.04.1
ProcVersionSignature: Ubuntu 5.15.0-67.74~20.04.1-generic 5.15.85
Uname: Linux 5.15.0-67-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.25
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: XFCE
Date: Wed Mar 8 07:51:31 2023
InstallationDate: Installed on 2019-12-05 (1188 days ago)
InstallationMedia: Xubuntu 19.10 "Eoan Ermine" - Release amd64 (20191017)
SourcePackage: linux-signed-hwe-5.15
UpgradeStatus: Upgraded to focal on 2020-07-10 (970 days ago)

[Jarno Suni (jarnos)]

Bug occurs with 5.15.0-69-generic, too.

[Jarno Suni (jarnos)]

Possible dubplicate: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2012953

[Jarno Suni (jarnos)]

$ inxi -G
Graphics: Device-1: Intel Xeon E3-1200 v2/3rd Gen Core processor Graphics driver: i915 v: kernel
           Display: x11 server: X.Org 1.20.13 driver: modesetting unloaded: fbdev,vesa resolution: 1920x1080~60Hz
           OpenGL: renderer: Mesa DRI Intel HD Graphics 2500 (IVB GT1) v: 4.2 Mesa 21.2.6

It shows that 1920x1080~60Hz mode is on, but the monitor tells it can not show the mode, even if it can with older kernel. Why is this?

[Jarno Suni (jarnos)]

Bug occurs with 5.15.0-71-generic, too.

[Jarno Suni (jarnos)]

Occurs with 5.15.0-75-generic

[Jarno Suni (jarnos)]

Occurs with 5.15.0-115-generic, too. That is the current default kernel of Xubuntu 22.04.

[Daniel van Vugt (vanvugt)]

Please try the latest HWE kernel by running:

  sudo apt install linux-generic-hwe-22.04

[Daniel van Vugt (vanvugt)]

Also I've noticed in a number of bug reports in the last few years that more recent kernels have become more fussy about display bandwidth requirements. So just installing a newer HDMI cable might solve it.

[Jarno Suni (jarnos)]

Using another HDMI cable fixed this with 5.15 kernel. 6.8.0-40-generic freezes on boot.

[Jarno Suni (jarnos)]

6.5.0-44-generic seems to work fine with the new cable, too.

[Daniel van Vugt (vanvugt)]

Thanks for your efforts.