Mesa driver: How do i check if colour range is limited

[ODTech]

So most of the games i play i noticed that the colours looks washed out.
How do i check if the colour range is limited like it is by default on windows?

Linux Mint 19.2
Kernel 4.15
Radeon RX580
Mesa driver from Valve's ACO enabled ppa.

[xdshot]

xrandr

[ODTech]

Originally posted by xDShot:

xrandr

Thanks i'm getting results on google now. I googled colour output for mesa and got nothing before..

[ODTech]

output_csc is supposed to be the RGB range setting for AMD in xrand but it's not present so i can't set it.

Anybody have any idea?

[Marlock]

I searched "xrandr output_csc amd rgb range" and got interesting results:


for X.org sessions:
https://askubuntu.com/questions/883988/xrandr-how-to-find-the-correct-rgb-full-spectrum-output-command-for-my-system

use this to check current output_csc status:

xrandr -v

if it's not currently set to "bypass" (and that is one of the listed options like in the linked question topic) you may want to change to it with:

xrandr --output HDMI-0 --set "Broadcast RGB" "bypass"

for wayland sessions things are different, here is some insight:
https://www.reddit.com/r/linuxquestions/comments/aj7ojy/has_anyone_successfully_enabled_full_rgb_range_on/

[ODTech]

Originally posted by Marlock:

I searched "xrandr output_csc amd rgb range" and got interesting results:


for X.org sessions:
https://askubuntu.com/questions/883988/xrandr-how-to-find-the-correct-rgb-full-spectrum-output-command-for-my-system

use this to check current output_csc status:

xrandr -v

if it's not currently set to "bypass" (and that is one of the listed options like in the linked question topic) you may want to change to it with:

xrandr --output HDMI-0 --set "Broadcast RGB" "bypass"

for wayland sessions things are different, here is some insight:
https://www.reddit.com/r/linuxquestions/comments/aj7ojy/has_anyone_successfully_enabled_full_rgb_range_on/

Thanks but all those discussion are around intel. I also found the ubuntu link, it's the most prominent one.

[xdshot]

Should affect AMD as well I think

[Marlock]

the first answer on the first link is actually AMD-specific:

The Broadcast RGB property is for Intel graphics cards. output_csc appears to be the AMD variant of the same thing.

output_csc is set to bypass in what you posted, which should be equivalent to the Full range (0-255).

You can try setting output_csc to other valid options, notably tvrgb (16-235).

edit: which also means my first post did have one mistake...

xrandr --output HDMI-0 --set "Broadcast RGB" "bypass"

should probably be:

xrandr --output HDMI-0 --set "output_csc" "bypass"

[ODTech]

Originally posted by Marlock:

the first answer on the first link is actually AMD-specific:

The Broadcast RGB property is for Intel graphics cards. output_csc appears to be the AMD variant of the same thing.

output_csc is set to bypass in what you posted, which should be equivalent to the Full range (0-255).

You can try setting output_csc to other valid options, notably tvrgb (16-235).

edit: which also means my first post did have one mistake...

xrandr --output HDMI-0 --set "Broadcast RGB" "bypass"

should probably be:

xrandr --output HDMI-0 --set "output_csc" "bypass"

Yes i realise that but when i do "xrandr --verbose" the "output_csc" is missing and the command you quoted returns an error.

I will post the output of the command and the error a bit later, maybe someone has some more insight.

[Marlock]

Originally posted by ODTech:

Yes i realise that but when i do "xrandr --verbose" the "output_csc" is missing and the command you quoted returns an error.

I will post the output of the command and the error a bit later, maybe someone has some more insight.

Ah, now I understand!

I've just been able to sit in front of my own PC (KM 19.2 with AMD RX580 just like yours, but over a 5.2.x mainline kernel, and the output_csc info is also not available...

Before running this check, I was going to say it's likely that all you needed to do is update the kernel from 4.15.x to 5.0.x and the feature would be supported. AMD GPU hardware support on the linux kernel has evolved massively between these two versions...

...but apparently this is yet not 100% supported on this model?! Or the feature is under some new parameter somewhere now... I should dig this up too.


PS:
Regardless of that specific issue, for gaming it might be worth changing to a newer kernel branch, given how much AMD GPU support changed since 4.15.

It's very easy and safe to upgrade the kernel on Linux Mint via the Update Manager. There is a specific menu entry for "Kernel Updates" and, once in it, you can choose the 5.0 branch and install it, then just reboot to test it.

It will let you keep older versions and will boot by default into the newest... but the boot menu always lets you choose older versions from the Advanced Options so even if it doesn't work, you can revert at will and just uninstall the faulty version. Given how easy it is to roll back, it's arguably safer than doing normal updates, even though you're swapping the system core :)


If you're feeling adventurous, there are even newer mainline kernel branches available (but not with Ubuntu-specific tweaks...). I'm on LM 19.2 with mainline kernel 5.2.x and it works great, flawless so far.

Gotta be careful though (in general I now keep a safe distance from the latest branch until it has 10 or more bug-fixing releases). Once I stumbled upon a data loss bug for ext4 partitions (on 4.20.x IIRC?) and it wasn't trivial to recover without losing stuff.

[ODTech]

The setting is still not present in 5.0 kernel but i think there is a slight improvement in the colour. There is definitely a massive improvement in performance when i look at Dishonored.