I recently made a post about my FreeSync certified monitor not supporting VRR over HDMI. I thought that there was VRR support over HDMI even for versions below 2.1 spec. Am I mistaken in my assumption¿? Has the HDMI forum prevented the implementation of FreeSync in the open source drivers¿?
Obligatory fuck the HDMI forum and the HDMI spec.
The Steam Deck only does VRR over Displayport. Valve has their own engineers working on every part of the software stack. It’s their own hardware and their dock. With all that, Valve still can’t get VRR over HDMI to work.
Fuck the HDMI forum.
TL;DR depends on your gpu.
Some monitors below HDMI 2.1 support the early version of freesync made by AMD, while others support a fragment of what became 2.1’s VRR. The former is supported only by AMD, while the latter by both AMD and Nvidia (Pascal and upper with latest drivers). If you have the former, the monitor is probably not compatible with DP’s official adaptive sync, so Nvidia won’t work even on DP.
But… Even if you have AMD, due to a bug in the driver, if you have a Polaris GPU it might not detect the vrr capability over HDMI (but will over DP). I know for sure that RDNA 2.5 cards support it, in theory it should work even for all Vega and Navi GPUs, but I haven’t tested it.
I remember listening to a rant from the WAN Show about it, so this seems to be the case, more or less.
I’ve also heard that FreeSync does work with DisplayPort.
Yeah I am aware that DisplayPort has adaptive sync support but my laptop hardware limits me to HDMI. Believe me I would much rather be using DisplayPort
Same here, in fact I didn’t know it was another one of those Linux-adjacent topics.
Have sexual intercourse with the HDMI Forum and the HDMI spec.
I think it works here between my MX Linux and a Dell 4K display, via HDMI
[ 12.255] (**) AMDGPU(0): Option "DRI" "3" [ 12.255] (**) AMDGPU(0): Option "TearFree" "true" [ 12.255] (**) AMDGPU(0): Option "VariableRefresh" "true" [ 12.413] (**) AMDGPU(0): TearFree property default: on [ 12.413] (**) AMDGPU(0): VariableRefresh: enabledI have freesync on my laptop with the inbuilt screen.
Me too!
I am guessing that is because the internal displays in laptops are connected using an embedded DisplayPort(eDP) and not HDMI
this is correct
I thought that there was VRR support over HDMI even for versions below 2.1 spec.
Yes, there is FreeSync HDMI, which is supposed to be supported on Linux, and which is unrelated to HDMI 2.1 VRR. Don’t see anything about the monitor supporting that though (LG 24GS60F based on your previous post). Nor anything about HDMI 2.1 VRR, it probably only supports VRR via DisplayPort Adaptive Sync.
Not anything about HDMI 2.1 VRR, it probably only supports VRR via DisplayPort Adaptive Sync.
I verified from the user manual that the freesync is supported over HDMI 2.0(Its a budget 1080p monitor so no HDMI 2.1). The issue seems to be that the HDMI forum has not allowed code necessary for FreeSync HDMI in the open source drivers. Fuck proprietary solutions. I hope that DP (through usb-c or mini DP) becomes the standard even in budget laptops which currently come only with HDMI.
Apparently so it does, and it says “HDMI Freesync” rather than “HDMI [2.1] VRR”. FreeSync HDMI is a completely different protocol and is supposed to work under Linux. Found a thread here, can you try
cat /sys/kernel/debug/dri/0/HDMI-A-1/vrr_rangeandedid-decode < /sys/class/drm/card0-HDMI-A-1/edid? Though there is no solution there.
