I am having an issue where the pixel clock of my UHD display is being limited to 165.0 MHz apparently, and I therefore cannot configure the display to it’s native resolution.
I am using nVidia Quadro P400 GPU with driver 381.22 on Ubuntu 16.04. The display is an LG Ultrawide with only HDMI inputs, so I am using an UHD-compatible active DisplayPort to HDMI adapter (Icybox IB-AC506; as far as I can tell DP v1.2 capable).
This is apparent in the logs (/var/log/Xorg.0.log):
[ 285.832] (--) NVIDIA(GPU-0): LG Electronics LG ULTRAWIDE (DFP-5): connected [ 285.833] (--) NVIDIA(GPU-0): LG Electronics LG ULTRAWIDE (DFP-5): Internal TMDS [ 285.833] (--) NVIDIA(GPU-0): LG Electronics LG ULTRAWIDE (DFP-5): 165.0 MHz maximum pixel clock
This is apparent when saving the EDID with nvidia-settings and using parse-edid:
Identifier "LG ULTRAWIDE" ModelName "LG ULTRAWIDE" VendorName "GSM" # Monitor Manufactured week 12 of 2016 # EDID version 1.3 # Digital Display DisplaySize 670 280 Gamma 2.20 Option "DPMS" "true" Horizsync 30-90 VertRefresh 56-75 # Maximum pixel clock is 240MHz
Why is this so? Is this a software bug? Hardware problem? Is the cable to blame? The adapter?
How do I diagnose this issue?
Any help is much appreciated.
nvidia-bug-report.log.gz (144 KB)