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Random screen flashing gsync compatibility LG C9
Posted: 28 Nov 2019, 13:59
by tygeezy
Hey guys, I got a lg c9 a couple of weeks ago. I’ve noticed that when I’m playing any games I get these random screen flashes or flickers. It can take a minute to happen or happen once every 10-15 minutes, but it’s extremely annoying. Does anybody have a clue what could be going on? I’m using a GeForce 2070 super with Windows 10 and a 7700k. It’s been happening on the last two game ready drivers, which are the only drivers I’ve used with this display. Here’s a video I was able to capture of it.
Re: Random screen flashing gsync compatibility LG C9
Posted: 28 Nov 2019, 15:01
by Chief Blur Buster
Hmmm.
Troubleshooting
Have you upgraded to the latest LG c9 firmware and latest NVIDIA drivers?
Or it only started to happen with the latest drivers?
Technical Explanation
For background knowledge;
I've seen VRR flashing happen with driver bugs or display bugs which causes:
(1) Refresh rate range to be exceeded (refresh interval beyond spec); or
(2) Buggy LFC (refresh-repeat creates a refresh interval outside VRR range spec); or
(3) Incorrect EDID/DisplayID timings or incorrect processing of (creating refresh interval beyond spec); or
(4) VRR slewrate beyond spec (frametime suddenly varies, like from top-of-VRR-range suddenly to bottom-of-VRR-range). This should not happen as there's no slewrate restriction but I've occasionally seen bugs from excess refresh rate slewrate (rapid change in Hz).
(5) Other VRR issues;
Or a combination of the above.
You could also see if there are settings that modifies LFC operation.
Adding an RTSS frame rate cap might help solve top-end-of-VRR-range spec issues, though not always.
Re: Random screen flashing gsync compatibility LG C9
Posted: 28 Nov 2019, 15:28
by tygeezy
Chief Blur Buster wrote: ↑28 Nov 2019, 15:01
Hmmm.
Troubleshooting
Have you upgraded to the latest LG c9 firmware and latest NVIDIA drivers?
Or it only started to happen with the latest drivers?
Technical Explanation
For background knowledge;
I've seen VRR flashing happen with driver bugs or display bugs which causes:
(1) Refresh rate range to be exceeded (refresh interval beyond spec); or
(2) Buggy LFC (refresh-repeat creates a refresh interval outside VRR range spec); or
(3) Incorrect EDID/DisplayID timings or incorrect processing of (creating refresh interval beyond spec); or
(4) VRR slewrate beyond spec (frametime suddenly varies, like from top-of-VRR-range suddenly to bottom-of-VRR-range). This should not happen as there's no slewrate restriction but I've occasionally seen bugs from excess refresh rate slewrate (rapid change in Hz).
(5) Other VRR issues;
Or a combination of the above.
You could also see if there are settings that modifies LFC operation.
Adding an RTSS frame rate cap might help solve top-end-of-VRR-range spec issues, though not always.
I’m on the latest firmware for my television. I e only used two drivers with this tv and this flashing happens on both.
According to lg this tv currently doesn’t support lfc. Here is a link to a discussion about it:
https://lgcommunity.us.com/discussion/c ... ment_15425
Things I’ve tried. Using different hdmi cables, disabling GeForce experience overlay.
I’m using maximum power in Nvidia control panel. I’m going to try setting it to default which I think is performance.
Also, Windows thinks I have two displays because I’m running a hdmi cable from my onboard intel gpu to my receiver so that I can get uncompressed 5.1 audio.
Earc on the tv currently will only send stereo pcm, but I’ll try unplugging the other hdmi cable so that I’m not getting a clone display to see if that will also fix it.
Also, I am using rtss to cap below refresh rate in this game. If a game has a in game capper I use that instead.
Re: Random screen flashing gsync compatibility LG C9
Posted: 30 Nov 2019, 01:33
by tygeezy
Okay, so I unplugged the hdmi cable going to my receiver and I’m now just using earc and the Dolby atmos app for the surround audio.
It seems to have helped, but now I just get it much less frequently. I believe it’s corresponding with a stutter.
I’m not the only person with this yo yo experience this. A few people on avs forum are also reporting this issue.
Re: Random screen flashing gsync compatibility LG C9
Posted: 01 Dec 2019, 02:44
by RealNC
If it corresponds with a stutter, that could mean the driver is not disengaging VRR mode when the frame time gets too high, and as a result the pixels undergo a "whiteout" due to not getting refreshed in time. So it could be a driver issue.
Re: Random screen flashing gsync compatibility LG C9
Posted: 01 Dec 2019, 14:00
by tygeezy
RealNC wrote: ↑01 Dec 2019, 02:44
If it corresponds with a stutter, that could mean the driver is not disengaging VRR mode when the frame time gets too high, and as a result the pixels undergo a "whiteout" due to not getting refreshed in time. So it could be a driver issue.
Yeah, I’m not sure if I t does or not. I’m not feeling a stutter when it happens. Is it possible I also have a faulty tv? I have coil whine coming from my tv as well.. I’m not the only person that has reported this issue with the flashing, but some people claim they don’t get it either.
On loading screens I will get a pulsing screen as well. I have an old gsync monitor that does that as well though, but it has zero issues in actual gameplay.
https://youtu.be/AbWbtsBuBJU
Re: Random screen flashing gsync compatibility LG C9
Posted: 02 Dec 2019, 16:57
by tygeezy
So i'm not the only person with this issue. Now, im not sure how widespread this is. Other people with c9's say they don't have an issue. Could it possibly be an issue with the panel itself? The uniformity on my panel is very good and i'm afraid of exchanging this for another c9, not fixing the flashing and then getting a panel with a lot of vertical banding and or horrible tinting.
https://lgcommunity.us.com/discussion/8 ... -c9#latest
https://www.reddit.com/r/OLED/comments/ ... ith_gsync/
Re: Random screen flashing gsync compatibility LG C9
Posted: 03 Dec 2019, 08:46
by RealNC
Your guess is as good as mine :-/
Re: Random screen flashing gsync compatibility LG C9
Posted: 03 Dec 2019, 14:58
by tygeezy
RealNC wrote: ↑03 Dec 2019, 08:46
Your guess is as good as mine :-/
I could have a tcon board failure... Check out this video from linus. The relevant info starts at 2:20, but the entire thing is worth a watch. LG is sending out a tech tomorrow that i've already briefed on the situation.
Re: Random screen flashing gsync compatibility LG C9
Posted: 04 Dec 2019, 02:46
by tygeezy
Deleted.