Bad 2d performance, tearing or freezing with Radeon.

The file /usr/share/X11/xorg.conf.d/20-radeon.conf contains some configuration workarounds for the radeon driver. They are commented by default (that is, they are all prefixed by the hash (#) character), which means they are not active. To activate them, you need to remove the hashes.

The configuration comes in blocks or sections. A section starts with "Section" and ends with "EndSection". You must remove (to activate) or add (to de-activate) hashes for a complete section, not only to a part of them.

The file above contains multiple sections, one for each workaround. Each workaround address a different problem. Please ensure that you only activate one of them. If you enable multiple sections, the result will be unpredictable.

The first workaround (the first section in the file) is to address tearing or overall poor 2D performance.

The second workaround (the second section in the file) is to address freeze or locks-up when powering down the machine, or when launching Xlock screen locking, or small 2D graphics glitches.

The third one only attempts to prevent screen tearing when during video playback, when running a composite manager (e.g. compton). Note that workaround #1 include tearing prevention also.