Set Full RGB on Intel GPU driven monitors

[ZetaArashi]

Have two monitors, one running on HDMI via Nvidia, another on DP via Intel. The Intel monitor doesn't output with Full RGB support, which means I get a reduced color range on the monitor.

HDMI, Full RGB being set by default:

DP, Limited RGB being used:

It's actually more dramatic in person, but hopefully the color disparity is visible.

Most of the ways I've attempted to set this outside of Hyprland have failed. Currently it seems to default to 'automatic' mode, which isn't giving Full RGB. (Queried using proptest -M i915 from libdrm)

This was apparently planned to be merged into wlroots a while back, and therefore rejected for Hyprland (see here). As wlroots never merged it, and Hyprland moved to Aquamarine, I thought I'd make the request for this to be settable in Hyprland in some capacity. Currently my only Wayland option for getting accurate colors on that monitor seems to be using KDE... which I would rather not do, because I want to use Hyprland. (Edit: I've already tried with all of the current monitor options including color management, no dice)

Wasn't sure if this should go in Renderer or Other, so apologies if it's in the wrong place.

[CallumFling]

I've got the same issue on my setup with an external USB-C docking station (usb-c displays are routed via the intel iGPU). Until this gets fixed properly someday, a workaround appears to be setting the affected monitors to a non-standard refresh rate so the intel GPU driver doesn't think the displays are TV's. For me, 58Hz does the job.

[UjinT34]

drm_info should show which properties are supported and their values. For nvidia it shows "COLOR_RANGE": enum {YCbCr limited range, YCbCr full range} = YCbCr full range. AQ doesn't touch this property and goes with the default value. Intel might have a different property name for this purpose and might have a different default value.
https://drmdb.emersion.fr/properties/4008636142/COLOR_RANGE

I don't think there is much need to make it a configurable setting. This should be an AQ issue.

[CallumFling]

Running proptest -M i915 -D /dev/dri/card0 on my machine reports out the property as Broadcast RGB. Not sure if this helps or not, but from a bit of searching around online this appears to be the intel specific term for the output range. It's got options of Automatic=0 Full=1 Limited 16:235=2. On xorg gnome this was the value that I had to change via xrandr.

The driver defaults to Automatic (value of 0) but there is likely some code somewhere in the driver that interprets the monitor as a TV, thus Automatic pointing to the limited range. And yeah this probably is more AQ related vs hyprland itself. I can open one there if it would help.