Vsync and tearing

[Sharft 6]

Hi there. I’m running NoMachine server on Ubuntu 20.04 with Ubuntu and Windows clients. Using the nvidia 495.46 proprietary driver on the server.

The main problem I’m having is with tearing. it looks great if I connect to NoMachine, then play a tearing test video of simple black and white bars. However if I try something a bit more demanding e.g. a full screen video with colour, within a few seconds of video playback, tearing begins. If I then pause the video and go back to the simple black & white tearing test, it looks torn to pieces. To recover from this I must end the NoMachine client session and then re-connect.

Something is changing when playing videos in full screen which causes severe tearing which persists until the session is ended. Any idea what it could be?

[fra81]

Hi,

what you describe is likely a driver issue. Just to exclude a possible culprit, please try to disable hardware encoding on the server (Server preferences -> Performance) and see if the issue persists.

If disabling hardware encoding doesn’t help, it would be nice to take a look at the logs. You can gather them following the instructions in https://knowledgebase.nomachine.com/DT11R00182 and send to forum@nomachine.com.

[Sharft 6]

I have flipped all of the options including hardware encoding and decoding on the client and server. None of the options seem to make a difference.

After doing a bit more testing I have discovered the following:

1. This doesn’t happen if the NoMachine client is running in a window.

2. This doesn’t affect Windows NoMachine clients at all, full screen or windowed I can’t replicate the issue on Windows.

I have flicked the logs through.

[fra81]

Hi,

so your last findings seem to narrow it down to a rendering issue on client side. I still think this could be an issue with the drivers, but, if you send us the client side logs, we can check for possible hints. You can find instructions in https://knowledgebase.nomachine.com/DT11R00181#2 for the client side. Please also tell us what graphics card and drivers you have on the problematic Ubuntu client.

[Sharft 6]

Alright I have sent through the client logs.

This has happened on all ubuntu clients I have tried and no Windows ones

The one i’m currently on has an Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller (rev 06)

with the i915 driver

[fra81]

There is no evidence of a NoMachine problem in the logs, so this really looks like a problem with the drivers, or anyway at the system level.

[Author]

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