Question HD 520 Graphics in Linux Mint 21.1 HDMI Quantization Range Issue

[Dave3000]

I have Linux Mint 21.1 installed as my OS for my Intel NUC. The issue I'm having with it in Linux Mint is that the HDMI Quantization range by default is set at Limited and displays a washed out look on my monitor when in Linux Mint. I found two workarounds to this issue, one being adding the command xrandr --output HDMI-1 --set "Broadcast RGB" "Full" as a startup command in the startup menu and the other workaround is adding that same command to the .profile file in my home directory. However, with these two workarounds, full range RGB only kick in after I log into the operating system, and as a result it looks washed out in the login screen then I log in and the screen blanks out for a second then the Full range RGB kicks in. What I want is full range RGB to kick in as soon as the login screen shows up and not after signing into the operating system. Is there a way to accomplish this? When I had Windows 10 installed on this PC, I could set it to full range RGB in the Intel Command Center app but in Linux Mint there is no such app and I couldn't find a Linux version of this app to download. Also, this PC is connected through an HDMI switch which is connect to my monitor via and HDMI-to-DVI cable. If I connect this system directly to my monitor via the HDMI-to-DVI cable, bypassing the HDMI switch, then it shows the proper quantization range as it doesn't look washed out.

 

[Insert_Nickname]

Also, this PC is connected through an HDMI switch which is connect to my monitor via and HDMI-to-DVI cable. If I connect this system directly to my monitor via the HDMI-to-DVI cable, bypassing the HDMI switch, then it shows the proper quantization range as it doesn't look washed out.

Sounds like an EDID issue with the HDMI switch. But how to fix it under Linux I don't know.

 

[VirtualLarry]

Sounds like an EDID issue with the HDMI switch. But how to fix it under Linux I don't know.

Maybe a physical EDID "spoofer box"? (Yes, they make these.)

 

[Dave3000]

Sounds like an EDID issue with the HDMI switch. But how to fix it under Linux I don't know.

I think you're right. I recently borrowed my mom's HDMI switch, a Rocketfish 4-port 1080P 3D, to test out and I'm getting full-range RGB in Linux Mint now. Is that an EDID issue with my HDMI switch like you said? However, one problem I have with her HDMI switch is that it won't show any image of the post screen during the boot up process.

 

[Dave3000]

I also tried an HDMI to VGA adapter as I wanted one less box on my desk and my monitor has a VGA input in addition to a DVI input and it has the same issue as my HDMI switch in Linux. The best workaround I found to the issue is creating a conf file in the lightdm.conf.d directory with this syntax:

[Seat:*]
display-setup-script=/home/david/xrandr.sh

xrandr.sh is a script file I created inside my home directory with this syntax:

!#/bin/bash
xrandr --output HDMI-1 --set "Broadcast RGB" "Full"

This will set the login screen to display as full-range RGB, not just after then login screen. Unfortunately the splash screen (the first screen that displays as Linux Mint loads up just before the login screen) is still displayed at limited-range RGB and I can't find a way for that screen to be displayed at full-range RGB. Also my monitor is still being detected as an HDMI-1 display when using the xrandr command in the terminal, despite now using an HDMI to VGA adapter.