MiSTer Freesync and LG CX TVs - Not Possible?

[Escape-To-88]

Hi all,

Having messed around a fair bit with the MiSTer now and having previously owned several CRTS and Freesync monitors I'm just looking to confirm my assumption that using the Freesync function the LG CX OLED TV isn't possible.

Using the green VRR button it reports what the core is running e.g. Neo-Geo at 59 and SNES at 60.10 but it says 'FIXED' and assume it isn't running as it only supports free and g-sync through HDMI 2.1, which Mister doesn't support. On Samurai Shodown 2 on the Neo despite it reporting the 59hz refresh rate the shadows flicker incorrectly and the background scroll pauses every few seconds very, very briefly.

On my old Freesync monitor with MAME and a DVI lead this didn't happen. Equally on my cabs this doesn't happen. I'm assuming the culprit is the TV but I'd like to know for sure.

[softtest9]

Do you experience these problems when VRR/Freesync mode is turned off in the TV's settings? If so, do you know what the TV's "Freesync range" is? If it is something like 50-75hz, it "should" just work, as 59hz and 60.10hz are within that range.

MiSTer has no support for Freesync, but you don't really need it. All consoles have a locked refresh rate, so the core will just change the TV's refresh rate when you start it and that's it. What really makes a VRR/Freesync display useful in the context of the MiSTer, is the generally wide range of supported refresh rates that a VRR/Freesync display tends to have (other displays might just support 60hz and that's it).

[Escape-To-88]

Do you experience these problems when VRR/Freesync mode is turned off in the TV's settings? If so, do you know what the TV's "Freesync range" is? If it is something like 50-75hz, it "should" just work, as 59hz and 60.10hz are within that range.

MiSTer has no support for Freesync, but you don't really need it. All consoles have a locked refresh rate, so the core will just change the TV's refresh rate when you start it and that's it. What really makes a VRR/Freesync display useful in the context of the MiSTer, is the generally wide range of supported refresh rates that a VRR/Freesync display tends to have (other displays might just support 60hz and that's it).

I don't think you can technically turn it 'off' as such. It reads the incoming rate correctly as the (hidden) freesync menu tells me what rate is coming in it definitely does not display it though and locks to 60. I belive free and g-sync should auto switch somehow via some kind of handshake protocol so I'm unsure if it just doesn't like it essentially since it doesn't have the option to technology 'turn on' VRR. I'll have a nose around and see if I can unearth some info about it on or off. It supports 40 - 120hz rates

[FoxbatStargazer]

Stumbled on this curious post on AVR forums. Says you need to enable freesync premium pro for the specific input and the results aren't necessarily great in terms of input lag. Plus flickering but I'm assuming that won't be much of an issue with a constant refresh rate.

[Escape-To-88]

Stumbled on this curious post on AVR forums. Says you need to enable freesync premium pro for the specific input and the results aren't necessarily great in terms of input lag. Plus flickering but I'm assuming that won't be much of an issue with a constant refresh rate.

Thanks mate. However I have enabled the 'Freesync Premium' option and still no luck. The worst offender is the SNES core when there is rapid horizontal movement e.g. Mario running in Super Mario World, I can see it not keeping perfect sync. It's made worse because I'm used to using my arcade cabs with their CRTs so I can see exactly when it isn't running smooth. The only option is to sync the core to exactly 60hz, which seems pointless to me as it is then inaccurate. Annoyingly despite the CX being able to do all sorts of VRR stuff it just doesn't seem to want to do it won't the MiSTer. I still think it's because it doesn't like the signal the MiSTer is sending or it's looking for some kind of digital handshake.

[Insert Disk Two]

I was planning to buy this TV because I had the impression that it can handle most funky frequencies without resampling to 60hz. So, this is incorrect? For example my 55" Panasonic always stutters when playing Neogeo games because of this reason.

[Insert Disk Two]

Hi all,
Having messed around a fair bit with the MiSTer now and having previously owned several CRTS and Freesync monitors I'm just looking to confirm my assumption that using the Freesync function the LG CX OLED TV isn't possible. Using the green VRR button it reports what the core is running e.g. Neo-Geo at 59 and SNES at 60.10 but it says 'FIXED' and assume it isn't running as it only supports free and g-sync through HDMI 2.1, which Mister doesn't support. On Samurai Shodown 2 on the Neo despite it reporting the 59hz refresh rate the shadows flicker incorrectly and the background scroll pauses every few seconds very, very briefly. On my old Freesync monitor with MAME and a DVI lead this didn't happen. Equally on my cabs this doesn't happen. I'm assuming the culprit is the TV but I'd like to know for sure.

I assume you are using vsync_adjust=2 in mister.ini?

[zakk4223]

TVs tend to be weirder with stuff like this than PC monitor panels for some reason.

Try enabling game mode on that input, or setting it to a "PC" input. (Or maybe even just renaming it to "PC", which matters on some TVs).

Maybe see if there's a firmware update too.

[Escape-To-88]

TVs tend to be weirder with stuff like this than PC monitor panels for some reason.

Try enabling game mode on that input, or setting it to a "PC" input. (Or maybe even just renaming it to "PC", which matters on some TVs).

Maybe see if there's a firmware update too.

Yup vsync adjusted to 2. It displays the rate the MiSTer is outputting e.g. 60.10 for Snes, but tells me the TV is locked to 60hz in the freesync Easter egg menu by a 'fixed' text box, when VRR works it switches to say 'VRR'. The scrolling through the Snes core is not correct on my OLED, having owned every iteration of the Snes and a Super NT I am very familiar with the system. I can only get it to run smoothly on the Mister and OLED if I change the vsync to lock to 60, which is then incorrect. On a CRT the Snes core of course runs perfectly.

I've enabled game mode, changed the input (via an icon on the OLED) to PC and checked for f/ware updates and still no dice. I did that before posting on here as seem to have exhausted every option. I'm getting close to running out of ideas. I'm slightly puzzled as to how other people are running this on there HDTVs accurately. I'm assuming they lock 60hz or just don't notice the slightly jerky scrolling?

[mistahsnart]

Sorry you're having this issue. My 65" CX reports the correct refresh rates with vsync=2. It's not Freesync obviously, because MiSTer doesn't support that, but the CX grabs the signal and reports the correct rate. Checking Neo Geo 15khz shadows against my CRT was the first thing I did, and all is well. It's my go-to test as I'm happy that I can retire my crystal modded MVS finally for big screen gaming.

Running the latest firmware. The ONLY "glitch" I ever get is when a game first loads on any core that isn't a locked 60. Just a brief black screen as the panel latches on to the rate.

I'm far from an expert on any of this, but enabling Freesync for that input seems necessary.

[Escape-To-88]

Sorry you're having this issue. My 65" CX reports the correct refresh rates with vsync=2. It's not Freesync obviously, because MiSTer doesn't support that, but the CX grabs the signal and reports the correct rate. Checking Neo Geo 15khz shadows against my CRT was the first thing I did, and all is well. It's my go-to test as I'm happy that I can retire my crystal modded MVS finally for big screen gaming.

Running the latest firmware. The ONLY "glitch" I ever get is when a game first loads on any core that isn't a locked 60. Just a brief black screen as the panel latches on to the rate.

I'm far from an expert on any of this, but enabling Freesync for that input seems necessary.

This is really interesting and gives me some vague hope - would you mind if I pmed you with a couple of questions? I'd be hugely grateful.

[softtest9]

Which refresh rates work will depend on the TV. My particular TV is not VRR, but it is pretty tolerant and will generally work fine with anything close to 60hz. Only with the NeoGeo core do I have to set the MiSTer to vsync adjust=0. But a lot of displays are more sensitive.

What's weird is that every core's refresh rate is well within your TV's Freesync range. It really should work just fine. I guess LG cut some corners in a weird way.

[mistahsnart]

Go for it! Happy to help troubleshoot. I'm starting to wonder if the CX has issues going ABOVE 60hz without Freesync support. The systems I'm familiar with at that level all operate below.

[Escape-To-88]

Go for it! Happy to help troubleshoot. I'm starting to wonder if the CX has issues going ABOVE 60hz without Freesync support. The systems I'm familiar with at that level all operate below.

Amazing. Thank you. Will PM now. I have issues with the Neo too, shadows don't displays correctly on my CX and the scrolling pauses slightly every few frames.

[Escape-To-88]

I've also attached a photo of the Freesync/refresh rate info you get when you spam the green button on the CX. As you can see it reports the correct refresh rate on Neo Geo coming but the '60hz Fixed' text tells you that's what the panel is currently displaying. I've also tried higher resolutions and get the same info.

[softtest9]

Very strange behavior from your TV. Have you contacted LG about this?

[Escape-To-88]

Very strange behavior from your TV. Have you contacted LG about this?

Not yet as tbh I'm unsure this is something which I could solve. I've pm'ed @mistahsnart and I'm hoping there is something obvious I'm missing.

[Escape-To-88]

Go for it! Happy to help troubleshoot. I'm starting to wonder if the CX has issues going ABOVE 60hz without Freesync support. The systems I'm familiar with at that level all operate below.

Pm'ed you mate. Thank you for anything in advance as it's driving me mad!

[mistahsnart]

Escape-To-88 and I are on it, and may have blown this whole "Freesync is perfect with MiSTer" case of perception wide open!

...ok, I'm exaggerating, but it prompted me to take a much more critical eye to a few things. Comparing notes now.

[Insert Disk Two]

Please keep the thread updated. I plan to buy a CX so I would know what I am getting into

@Escape-To-88 maybe there is something which is forcing the panel to resample to exactly 60hz?

[mistahsnart]

Please keep the thread updated. I plan to buy a CX so I would know what I am getting into

@Escape-To-88 maybe there is something which is forcing the panel to resample to exactly 60hz?

Will do, and that's my early thinking too. We're both of the mind that the issues are FAR less noticeable than they were on 60hz fixed panels, but still ever so slightly present when you really start looking. Doing a long run in a stage in Super Mario World reveals that the little fullscreen 'hitch' when running off sync is there still, but again, it's not as jarring (to me) as I remember the SuperNT being running in correct timing on this same display. This certainly all warrants deeper exploration.

[Escape-To-88]

Please keep the thread updated. I plan to buy a CX so I would know what I am getting into

@Escape-To-88 maybe there is something which is forcing the panel to resample to exactly 60hz?

Will do, and that's my early thinking too. We're both of the mind that the issues are FAR less noticeable than they were on 60hz fixed panels, but still ever so slightly present when you really start looking. Doing a long run in a stage in Super Mario World reveals that the little fullscreen 'hitch' when running off sync is there still, but again, it's not as jarring (to me) as I remember the SuperNT being running in correct timing on this same display. This certainly all warrants deeper exploration.

Like yourself I never noticed this on the Super NT and I've played Mario World to death. Equally using a one chip console (before I sold it off) and an OSSC I never noticed the issue either. Doing a play test of Mario World on a CRT and then the CX, there is zero issues on the CRT which would indicate it's the OLED panel not the core. Frustratingly I sold my NT. Although he's a good buddy of mine who I could get to do a similar test. Oddly if you run the MiSTer through an OSSC into the OLED I'd say the slight frame stall is less noticeable again, but still not smooth.

[mistahsnart]

Now we have to wait until we find someone with a C1 to learn if we both get to regret our CX purchases.

[Escape-To-88]

Now we have to wait until we find someone with a C1 to learn if we both get to regret our CX purchases.

[Escape-To-88]

Now we have to wait until we find someone with a C1 to learn if we both get to regret our CX purchases.

So I've had confirmation FIXED definitely means it is locking to 60hz rather than the rate of the MiSTer. I can see myself buying back my PVM or picking up another PC monitor...eugh.

[Insert Disk Two]

Can fixed be switched off? Is everyone getting the "fixed" message?

[Escape-To-88]

Not that I'm aware. Yup everyone is it seems. It reports VRR instead of fixed when it switches to match the refresh rate like on on Series X. Using a Series X you need to enable Freesync on the console to get it to switch as I'm assuming it sends the expected signal and handshakes with it. I'm wondering if it doesn't like it simply because you can't alter that kind of thing the MiSTer end, although vsync=2 is clearly sending the correct refresh rate for the cores.

[Insert Disk Two]

I find it strange that no one has commented/noticed this before, especial Atrac17.

[Escape-To-88]

I find it weird too. So much so I did several tests. The two most obvious and the scrolling pauses in the Samurai Spritis II background on the character select screen and the Mario World one. I find the latter unplayable. Maybe because I am so familiar with Mario World? Any length where you have a straight run you can see the issue on that game. Running them one after the other first CRT then the CX makes it immediately obvious. Both @mistahsnart testing matches up also.

[Insert Disk Two]

The test I do is Samurai Shodown 4 on Neogeo. Watch closely the Japanese text on the intro as it scrolls sideways. If it stutters, the TV is shit