MiSTer FPGA Forum

Hi,
I recently got a new S95B TV (2022 model) that supports VRR, up to 120Hz. I tried to setup my MiSTer to take advantage of it, following the great documentation at "https://mister-devel.github.io/MkDocs_M ... sics/video".
In the .ini config file, I tried setting "vsync_adjust" to either 1 or 2, coupled with "vrr_mode" at 1 or 2 (for Freesync Premium). To test those settings, I ran a couple cores, Dodonpachi (arcade) at 57Hz, and PowerStrike II (SMS Pal) at 50Hz. The TV correctly detects that Freesync is on, and displays the correct refresh rate for both games, but I unfortunately get a fixed screen tearing line (that is always there and exactly at the same position), that makes the games basically unplayable (with an input lag that is good when on the top part of the screen, and terrible below the tear line). I got these exact same results no matter what combination of "vsync_adjust" and "vrr_mode" I tried (with values at 1 or 2). Note that for the sake of it, I also tried mode 3 for "vrr_mode", but this flat out failed and I would not get any display at all from my MiSTer.
Has anyone experienced something similar with VRR-supporting screens? Any clues on what could be done?
Cheers,

Few more precisions/findings:

• I'm on the latest (as of 6/25/2023) TV firmware, v. 1503, and also on latest update_all versions for MiSTer.

• I tried various HDMI cables to exclude any potential issue with connection, and up to a full 2.1 48 Gbps cable, that I also use with my PC.

• Speaking of PC, VRR works perfectly fine on this TV from the computer, with a 40series NVidia card, and with a refresh rate up to 120Hz.

• I can use MiSTer in "vsync_adjust" modes of 1 and 2 (without VRR on) and it works perfectly fine in standard freqs of 50 and 60Hz. My test for 50 was again SMS Pal with Powerstrike II and it worked brilliantly, no tearing whatsoever (Out of curiosity, I also tested those same common frequencies on a Pal Wii with Gamecube games, and again worked like a charm). That same MiSTer test without VRR doesn't work however, with less common refresh rates like 57 or 75Hz, in which case I lose the display.

• I managed to get the VESA VRR (aka GSync) to work (as in, display something as opposed to blank screen, but i still get the same tearing artefact), for this I had to set "vrr_vesa_framerate" to 60 in addition to "vrr_mode" to 3. I can see that my TV correctly detects it, as it displays "Freesync Premium" when Freesync is on, and simply "On" when GSync is active, in the VRR field of its gamebar.

• No matter what mode of "vsync_adjust" I set, 1 or 2, I get the exact same tearing artefact. For all I can see, MiSTer outputs the expected refresh rates, and the TV looks to be aware of them, as it properly displays them on the gamebar (see Dodonpachi screenshot below, for instance).

• I tried 3 different cores: SMS PAL (50Hz), Dodonpachi (57Hz) and Wonderswan Color (75Hz). I get this horrible "screen split in two by a tear line" artefact with SMS and DDP, but the Wonderswan Color seems to be working perfectly fine at 75Hz...

The latest point has me wondering: do the cores have to be updated to a specific framework to correctly support the VRR feature? Could it be why Wonderswan seems to work alright, whereas Dodonpachi and SMS PAL failed?
Thanks for reading through this, any help would be more than welcome!

Dodonpachi screenshot (artefact not visible on still image, but you can see the VRR settings are taken into account by the TV):
https://drive.google.com/file/d/1q-qHxM ... 18Zzk/view

So I've only had my MiSTer up and running for a few days, but I've just got VRR working with my LG CX by adding these settings into the ini file so might help you -

[MiSTer]
video_mode=8
vsync_adjust=2

hdmi_game_mode=1

vrr_mode=1
vrr_min_framerate=0
vrr_max_framerate=0
vrr_vesa_framerate=0

I've got game mode and Freesync both enabled for the HDMI input, and before these changes in arcade cores I was getting a default 720p fixed at 60fps.
With the changes applied, then I get the TV notification that gaming mode is on, and a 1080p picture with VRR confirmed running!

I've not gone through lots of games yet, but I think theres still some tweaks needed.
When I tried Frogger, it would show 2/3 seconds of the attract mode, and then blank out the display for a few seconds - and then just keep looping around like that.
I'm also running it through a cheap, auto sensing HDMI switcher as well, so that could also be causing some issues perhaps?

Either way, other games are working great for me right now!

All that 50/55hz stuff works perfectly on my LG C1 in freesync. So its not like there is some general VRR problem with mister. Its not interacting well with your specific TV model for whatever reason.

One thing you could try is playing with your output resolution. Try 1080p, and maybe supply cvt and non-cvt modes. e.g.

video_mode=1920,1080,60,cvt