Wayland session running at half of the selected refresh rate on Nvidia driver
Affected version
- OS version: Fedora 34
- Mutter version: 40.4 and 40.3
- Wayland only
Bug summary
GNOME Wayland session is running at half of the refresh rate selected in GNOME Settings–Displays. This is with an Nvidia 3060 card, driver version 470.63.01 and 470.57.02 (didn't try earlier driver or mutter version). I have a 165Hz laptop display and a 60Hz external display, and these refresh rates are indeed selected in GNOME Settings. But the 165Hz display is running at about 82Hz and the 60Hz display at 30Hz. If I set the refresh rate to a lower one, for example, 30Hz for the 60Hz display, then it runs at 15Hz.
Steps to reproduce
- Start GNOME Wayland session
- Choose 165Hz and 60Hz refresh rates in GNOME Settings–Displays (
xrandr
also shows the selected refresh rates) - Observe the refresh rate of GNOME Shell, mouse cursor movements, animations, etc (I'm not sure how to measure it)
- Run
glxgears
and read fps from the output or tryhttps://www.testufo.com/
in Firefox (native Wayland) - Also try other refresh rates
What happened
GNOME Shell desktop seems to be slower than the target refresh rate and other applications with fps counter show that they are always running at half of it.
What did you expect to happen
They should be running at the same refresh rate as selected in Settings.
XOrg session works as expected although the refresh rate for both displays must be the same. KDE KWin Wayland session works as expected, with per-display refresh rate. So I thought this might be an issue in mutter.