Apologies for the big messy merge. Upstream now have a patch for this, currently pending review, which applies cleanly to Debian mutter 3.21.92-1 and fixes the knock-on problems in gnome-shell etc.
https://bugzilla.gnome.org/show_bug.cgi?id=771628 https://bugzilla.gnome.org/attachment.cgi?id=335863&action=diff With my patched local build, all the hardware I've tested now works and doesn't crash gnome-shell in wayland or xorg. -- Andrew Chadwick
