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.
Actually it works fine on Steam Deck. It uses VRR over DP to the dock, which then translates it to HDMI with VRR. The dock has proprietary firmware to do this.
Intel and Nvidia hardware with open source kernel drivers also do a similar trick where the HDMI part is in a firmware blob. Only AMD does not work with HDMI VRR.
Source? So it can do 4k, 120hz+ VRR? I have found comments and change logs, but I’m not sure it fixes the HDMI 2.1 issue. Which would be 4k+ @ 120hz+ with VRR.
NM I found what I was looking for.
https://overkill.wtf/steamos-3-5-5-brings-just-so-much-stuff-including-vrr-for-steam-deck-dock/
Looks like it just gets VRR working, generally. Unfortunately not some kind of 2.1 workaround.
It would allow them to do HDMI FRL also, which is probably what you mean when you say HDMI 2.1. AMD cards also do HDMI FRL I thought. FRL is what allows things like 4k120Hz (higher bandwidth modes). The VRR that the Dock does is the VRR standardized with 2.1, which is why it works on TVs and devices that do not support freesync (see: LG TVs).
Anyway, the Dock doesn’t have a fast enough HDMI converter to do that. It’s not a licensing issue. Next gen Deck/Dock will probably do it.
“Obligatory fuck the HDMI forum and the HDMI spec”
Amen to that
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
Has been an ongoing issue and well documented. This is why I can’t use an AMD GFX card with my workstation.
This is also one of those stubborn “Linux” problems that new users run into and deters them from using the OS. It’s a BIG issue to have this caveat on Linux and keeps professionals from the platform.
Everyone will yell about switching to display ports and downvote. Happens every time it comes up. Then they will tell you to use an adapter. Adapters will not magically give your 4k 120hz+ VRR. But they will insist. It never ends.
In some ways, pushing people towards DP is good because it is a better spec than HDMI for the consumers in general and for the open source community specifically. The issue is that people are too zealous in recommending and pushing it.
In my case, I dont care much for VRR (Years of playing on crappy hardware have made me somewhat immune to tearing). I was just curious hence the post. Switching to display port is not an option since my laptop has no DisplayPort support whatsoever.
Not at 4k and above 60hz.
https://www.tomshardware.com/pc-components/gpus/hdmi-forum-rejects-amds-hdmi-21-open-source-driver
I’m using a Dell 4K monitor at 60Hz and in my X log I can see VRR is on and enabled. Is this useless then?
People like you disgust me. You intentionally ignore the root of the problem and instead direct your frustration and blame at the victim of said problem.
You absolutely should not be blaming Linux for this, this is the HDMI forum’s fault.
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.
