Dear Maintainer,

Fullscreen video drains a lot of CPU and has slow performance. Tested
with VLC, Totem and also youtube videos, all the time the same behavior.

Tested the same in Gnome and performance looks good,  so apparently it
is related to the desktop environment.

Note that the performace issue is only present in fullscreen mode on an
external display through HDMI. Local display works fine.

Regards.

Hi,

sorry for the very long delay in answering.

This report is against cinnamon 3.4.6 with muffin 3.4.1, clutter 1.26,
mesa 17.2 and kernel 4.13, a stack that no longer exists: muffin has
since been rebuilt on top of a modern mutter, with separate X11 and
Wayland compositors and per-CRTC frame clocks. The report also lacks the
information needed for a graphics performance issue: no GPU model, no
driver in use, no external display resolution or refresh rate, and no
indication of which process was actually consuming the CPU.

For the record, on X11 muffin only bypasses compositing for a fullscreen
window when the application asks for it via _NET_WM_BYPASS_COMPOSITOR;
otherwise every frame goes through the compositor. This can be changed
with:

gsettings set org.cinnamon.muffin unredirect-fullscreen-windows true

at the cost of possible tearing.

I'm therefore closing this bug. If you still see the problem on trixie or
sid, please open a new report including your GPU and driver, the external
display mode, and which process is using the CPU.

Thanks for the report,
Fabio