[SOLVED] Vsync only works when Settings window is open

[bradleypariah]

Experiencing an odd bug. V-sync simply will not work unless I keep the Settings > Display & Monitor > Compositor window open.

I am on an Intel machine with a gtx680. In the Nvidia Control Panel, "Force Full Composition Pipeline" is checked, but I am getting crazy screen tearing all the time. If I simply open Settings > Display & Monitor > Compositor, screen-tearing stops in every application. I don't even need to change any settings; it just starts working as intended, the moment the Settings are open.

As soon as I close the Settings window, screen tearing starts back up again in every application.

Kubuntu 20.04, Nvidia Driver 450.82.02

P.S. - If the Settings window is open on Desktop #1, I will get screen tearing on Desktop #2 through 4. Screen tearing is only controlled by Settings on the desktop on which the Settings window is active.

P.P.S. - If I switch my compositor Rendering Backend to XRender, I don't experience any screen tearing, but none of my desktop animations work.

[GreyGeek]

https://docs.nvidia.com/deploy/drive...nce/index.html

[jasoncollege24]

Some questions:

1. Is this an upgrade from a different version of kubuntu, or a clean install?
2. If it's a clean install, did you keep your previous home directory?
3. How did you install your drivers? If you downloaded them from the nvidia website, instead of getting them through the kubuntu repos... even nvidia recommends against that.
4. have you checked to see if the drivers you're using are the recommended drivers for your card?
5. Have you tried using nvidia-settings commands, instead of the xorg.conf file? Here's an example of one of mine.

nvidia-settings --assign CurrentMetaMode="HDMI-0: 1920x1080 +0+0 {ForceCompositionPipeline=On}"

The following command will tell you which drivers are recommended for your nvidia card.

ubuntu-drivers devices

If you agree with the recommendation, and are already using drivers from the repositories, this command will install the recommended driver for you

sudo ubuntu-drivers autoinstall

[bradleypariah]

1. Is this an upgrade from a different version of kubuntu, or a clean install?
I'm running 20.04, which was upgraded from 18.04.

2. If it's a clean install, did you keep your previous home directory?
N/A

3. How did you install your drivers?
Kubuntu downloaded them automatically. Back when I used 18.04, I had to add a GPU PPA, but 20.04 no longer needs it.

4. have you checked to see if the drivers you're using are the recommended drivers for your card?
No. I'm just running the latest/greatest. I will run the code you provided when I get home tonight.

5. Have you tried using nvidia-settings commands, instead of the xorg.conf file?
Yes.

[bradleypariah]

https://docs.nvidia.com/deploy/drive...nce/index.html

Interesting. I've never heard of persistence mode. Thank you! I'll enable this when I get home tonight. Hopefully that'll be it!

[bradleypariah]

[FONT=monospace][COLOR=#000000]sudo nvidia-persistenced --user (me)[/COLOR][/FONT]

Yields:

[FONT=monospace][COLOR=#000000]nvidia-persistenced failed to initialize. Check syslog for more details.[/COLOR][/FONT]

I ran

cat /var/log/syslog

and the most recent output from that time period is:

[FONT=monospace][COLOR=#000000]Dec 31 09:18:42 s5780t nvidia-persistenced: Failed to open PID file: Permission deni[/COLOR]ed 
Dec 31 09:18:42 s5780t nvidia-persistenced: Shutdown (9261)[/FONT]

According to Answer #1 here: https://askubuntu.com/questions/7088...ed-not-working
It's because the service may already be running, which I verified it was.

I went to Settings > Driver Manager and found out I am one version behind. I was running 450.x, but apparently the latest is 455.
I upgraded, then ran

sudo nvidia-settings

Then checked both of the Composition Pipeline check-boxes, rebooted, and so far so good! Thanks, all. Marking as solved.

[jasoncollege24]

Good stuff. FYI, it's not recommended to force the full composition pipeline, because it causes a performance hit. Just using the pipeline checkbox on the left should be enough.