RTX 2080Ti: 3 ports at 60 Hz, but one port limited to 30Hz

Graphics / Linux Linux
1

We have 4 displays connected to all ports on the RTX 2080Ti: 2 x 4K LCD and 2 x 1080p DLPs. We have two such cards, so there are 8 displays in total. All are running under Ubuntu 20.04, Driver Version: 470.256.02.

On the first 2080Ti, the HDMI port always recognises the connected display to be 30Hz, even if the display is 60Hz. When we connect the same display to a different port or a different graphics card, it is recognised as 60Hz (see the screenshots).

All displays are driven HDMI, and we have various dongles to convert from DP->HDMI or USB-C->HDMI. All dongles are labelled “4K” and we tested many of them. All cables are “4K” and 60 Hz and we tried many of them.

On the second 2080Ti, we have the same situation with the USB-C port - whatever we connect (4K LCD or 1080p DLP), it is recognised as a 30Hz display. The 2080Ti were purchased separately and are branded differently.

Does 2080Ti have a limitation on how many 60Hz displays it can drive? What could be causing one of the ports to be running at 30Hz?

We need all displays to be running at 60Hz.

The attached bug report was generated from a remote terminal. I hope it captured all the required info.
nvidia-bug-report.log.gz (1.4 MB)

gpu1_dp1
gpu1_dp1922×852 149 KB

2

At least I wouldn’t know of any such restriction. Also, the connections of the connectors in question seem to work fine:

NVIDIA(GPU-1): Morse Technology MEiTiAN (DFP-2): 600.0 MHz maximum pixel clock
NVIDIA(GPU-2): Morse Technology MEiTiAN (DFP-5): 2660.0 MHz maximum pixel clock

only issue is with one Acer projector on the second gpu which seems to be connected through a bad passive DP2HDMI cable:

NVIDIA(GPU-2): Acer 1080P PJ (DFP-4): 165.0 MHz maximum pixel clock

but in your case, this doesn’t matter.
Since the 470 legacy driver is out of support now, please check with a current 560 driver. If it still doesn’t work, please create /etc/X11/xorg.conf.d/nvidia-modedebug.conf

Section "OutputClass"
    Identifier "nvidia-modedebug"
    MatchDriver "nvidia-drm"
    Driver "nvidia"
    Option "ModeDebug" "true"
EndSection

and create a new nvidia-bug-report.log after reboot.