I found that launching LibreOffice Writer with default modesetting DDX and Panfrost driver cause Xorg process to take 100% of one SoC core and slowdown rendering significantly. Mutter render one frame per 5-15 seconds, so it's unusable until I close LibreOffice Writer (sometimes I had to do it remotely as doing so locally is painfully slow).
Ubuntu Eoan with Armbian 5.3.0-rc4-rk3399 kernel, which was built from 5.3.0-rc4-1118-ayufan tag of https://github.com/ayufan-rock64/linux-mainline-kernel repository.
Mesa 19.3.0 git (build from commit f8887909c6683986990474b61afd6d4335a69e41) with enabled Panfrost, from Oibaf PPA.
Gnome Shell 3.34 Beta.
glxinfo -B report "direct rendering: Yes" and "OpenGL vendor/renderer string: panfrost"
es2_info report GL_RENDERER: panfrost
Both of glxgears and es2gears_x11 run at ~60 fps.
NanoPC-T4 with active cooling.
Please let me know what information I can provide to help resolve this.