Comment 11 for bug 2044718

And:

#!/bin/bash

# Glamor should not run on platforms prior to Pi 4.

if ! raspi-config nonint gpu_has_mmu ; then
        if ! [ -e /usr/share/X11/xorg.conf.d/20-noglamor.conf ] ; then
                cat > /usr/share/X11/xorg.conf.d/20-noglamor.conf << EOF
Section "Device"
        Identifier "kms"
        Driver "modesetting"
        Option "AccelMethod" "msdri3"
        Option "UseGammaLUT" "off"
EndSection
EOF
        fi
else
        if [ -e /usr/share/X11/xorg.conf.d/20-noglamor.conf ] ; then
                rm /usr/share/X11/xorg.conf.d/20-noglamor.conf
        fi
fi