Tearing on 390 KUbuntu 17.10 K1100M Optimus?

GPU Unix Graphics Linux
#1

I have a weird problem I’d like help with. I’m using NVidia drivers + Intel drivers on my W540 Lenovo laptop. It seems like in the middle of the screen, when the screen must update fairly often, there is a weird tearing as best as I can tell in the center. It’s almost like the screen is split in half from the left side to the right.

This usually happens during a video or if I’m scrolling real fast in Chrome or Firefox. It doesn’t seem to make a difference if I have an external monitor or not.

Are there any ideas on this one?
nvidia-bug-report.log.gz (140 KB)

#2

Prime sync
To get rid of tearing, use kernel parameter

nvidia-drm.modeset=1

In case of Ubuntu, you might have to add/alter a file in /etc/modprobe.d/ containing

options nvidia_XXX_drm modeset=1

with XXX being the major version of the installed nvidia driver.
After that, run
update-initramfs -u

#3

D’oh forgot that. It does make tearing better. I’ll report if it’s fixed tomorrow when I go back to work on my 3 external monitors.

#4

Ok still having issues. It’s not as obvious but when I use Chrome and am scrolling on Facebook, I can see a difference. I see tearing across the image in the center.

I’m running 3 external monitors and 1 laptop display. The settings I have are configured for the internal and one external using Intel and the other 2 external ones on NVidia from my BIOS config and NVidia settings.

Thoughts?

#5

Please run nvidia-bug-report.sh as root and attach the tar.gz file it creates to your post.
In case of external displays connected directly to the nvidia gpu, use option ForceCompositionPipeline.

#6

Tried and still no difference. Bug report attached to original post.

#7

Is tearing on the internal panel, the external, or both?
The external panels have a native resolution of 1680x1050 but you run them at 1920x1080, so the display scales. Tried running them at their native resolution to rule out tearing resulting from display scaler?

#8

External mainly. I think the internal and one Intel external just lag a bit.

I just tried native on all monitors, and nothing.

Thanks for the help on this.

#9

Maybe also look into the kwin direction:
https://devtalk.nvidia.com/default/topic/783555/vsync-issues-tearing-in-kwin-with-composite-enabled/

#10

Maybe. I think it happens on Gnome as well.

#11

modeset=1 can only help with tearing on the outputs attached to the intel card.

If you are seeing tearing on other screens, try forcing pipeline composition perhaps (it’s a per-output setting in the nvidia control panel under advanced, but you’ll only see it as an option for outputs connected to the nvidia card). I think how much effect this has depends on the compositor. On my laptops it gets rid of tearing when using xfce (and it’s quite bad otherwise). When I use Cinnamon on Ubuntu 17.10 I have no tearing at all, even without using forced pipeline composition. I have a W520 and a P50. I haven’t put Cinnamon on the W520, it runs either gnome or xfce, and my observations are valid for both laptops (for the W520, I believe the VGA output is connected to the intel card, but I use the Display Port which is connected to the Quadro card).

#12

Hmm. I’m not sure about the DE, as Gnome seems to have the same problem.

I just went to using the Intel card for now on my 3 external monitors (better anyway for posture since my monitors are at eye level). Unless a fix comes out or anything I’ll just leave the loop closed.

It seems the NVidia drivers may just not be as developed as the Intel ones, especially not supporting Wayland.