Weird draw artifacts with Nouveau and Plasma

[enolan]

Issue description

When running Plasma with the Nouveau drivers, I see various strange artifacts when I mouse over things, type in the terminal or Firefox and in other situations. They look like discolored rectangles. They persist for a while, sometimes going away on their own and sometimes until I do something else like mouse over the control again. I assume they're showing up and disappearing when that area of the screen is redrawn. My monitor is 4k resolution which may or may not be relevant. Here is a bug report of the same problem on Fedora. There are some screenshots in there, but on my system taking a screenshot actually clears it, both in the screenshot and on the screen itself. I recorded a short video. That's me holding shift and left arrow.

Steps to reproduce

Install NixOS 17.09 from a USB stick onto a machine with an Nvidia GeForce GTX 760. Set services.xserver.desktopManager.plasma5.enable = true in configuration.nix. Reboot and log in. Mouse over things, type, select stuff, etc until this happens.

Technical details

Please run nix-shell -p nix-info --run "nix-info -m" and paste the
results.

 - system: `"x86_64-linux"`
 - host os: `Linux 4.9.85, NixOS, 17.09.3126.700a717ce9d (Hummingbird)`
 - multi-user?: `yes`
 - sandbox: `no`
 - version: `nix-env (Nix) 1.11.16`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs`

Here's my configuartion.nix: https://gist.github.com/enolan/2e4a40d447ce3c2e7dc2b0aa76db37ac

[va1entin]

I've had some issues with Nouveau drivers and Plasma aswell on a GTX 650. Ended up switching to proprietary nvidia drivers, which work without any problems so far, would love to use nouveau instead though!

services.xserver.videoDrivers = [ "nvidia" ];

[stale]

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