From cbd6920b9620a1b893e6c8fe05c3f7cc04ce98e8 Mon Sep 17 00:00:00 2001 From: Rick Peters Date: Thu, 1 Oct 2026 18:26:25 +0200 Subject: [PATCH] nvidia: TTY-only KWin stutters, Big Picture in Plasma is perfect --- nvidia/HARDWARE-RESULTS.md | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/nvidia/HARDWARE-RESULTS.md b/nvidia/HARDWARE-RESULTS.md index 88f3946..50b0911 100644 --- a/nvidia/HARDWARE-RESULTS.md +++ b/nvidia/HARDWARE-RESULTS.md @@ -46,7 +46,18 @@ CachyOS, Limine, kernel 7.2.8-1-cachyos, nvidia-open 615.71.09, gamescope 3.16.3 - Open: a real session entry (`/usr/share/wayland-sessions/`, needs sudo) and the product decision: an NVIDIA session mode in Steamify instead of the gamescope DRM session. Not built, not in the product repo. +## Smoothness: the TTY-only KWin session stutters, Plasma does not; Big Picture in Plasma is perfect (2026-10-01, evening) +- TTY session (`kwin_wayland --drm` under `dbus-run-session`, no Plasma): the mouse and windows stutter every 1-2 s, with gamescope + (clunky) and without it (`steam -gamepadui` as KWin's only client). Same in both: not gamescope, not Steam. Plasma's own KWin is smooth. +- Tried without effect: `KWIN_DRM_DISABLE_TRIPLE_BUFFERING=1`. Measured: the test KWin used about 2% CPU, no spikes, but its main thread + dropped to 0% about every 2 s (blocked, not busy); scheduling (RR main thread, nice -12) and capabilities equal to Plasma's KWin; + NVIDIA is boot_vga; no relevant environment differences found. Cause of the stutter not found. +- Plain `steam -gamepadui` (Big Picture, no gamescope) in the normal Plasma session: **perfect** (smooth, no artifacts, no env var needed). +- Direction: for NVIDIA PCs a Plasma session that shows only Steam's Big Picture (no desktop, no panel) instead of the gamescope + session. Gives up gamescope's features (HDR handling, FSR, overlay; most `-steamos3` menus need gamescope). + ## State of the PC after the test (to undo) - The fix is applied (Limine file backup `/etc/default/limine.bak-gamescope-wizard`, early-load file, pacman hook): undo in INSTRUCTIONS.md. +- Test launcher `~/.local/bin/steamify-nvidia-session-test`, log `~/steamify-nvidia-session-test.log`. - User override of the gaming session: `~/.config/systemd/user/gamescope-session.service.d/steamify-nvidia-test.conf` and `~/.local/share/steamify/nvidia-test/`.