xfwm4

using libxpresent

With some AMD Zen APUs (e.g. Ryzen 2500U (Raven) and 3550M (Picasso) xfwm4-4.14.0 produces text which is slow to render (e.g. tooltips are unreadable for a second or two, similar problems in terminals, e.g. text hard to read except when the cursor is on it. Also described as transparency artifacts. see e.g. ​https://forum.xfce.org/viewtopic.php?id=13232

The problem might only appear if the machine is a laptop, or perhaps it is related to Display Port outputs (my 2550U uses eDP according to xrandr, my 3400G desktop (Picasso) is connected to HDMI).

The compositor can also get turned off, killing the desktop.

Quoting from that forum, "In xfwm4, glx is the default vblank mode, but it also supports xpresent (which I believe works best for ati cards) and you can also turn it off."

As a workaround, setting the vblank mode to off works (you need to be in X to do this, perhaps using a different windowmanager if the compositor has turned off and is 'sulking' - it certainly gives that impression on _my_ laptop, requiring several reboots to sort it out)

xfconf-query -c xfwm4 -p /general/vblank_mode -t string -s "off" --create

That appears to work, but setting it to xpresent is probably better:

xfconf-query -c xfwm4 -p /general/vblank_mode -t string -s "xpresent" --create