Invalid cursor plane updates
Unfullscreening and then moving the wayland-fullscreen test client (swick/mutter@7eebc344) results in a bad KMS update:
libmutter-Message: 21:52:23.596: KMS: [atomic] Processing update 1147
libmutter-Message: 21:52:23.596: KMS: [atomic] Assigning cursor plane (52, /dev/dri/card1) to 0, 0x0+0+0 -> 0x0+0+0
libmutter-Message: 21:52:23.596: KMS: [atomic] Setting plane 52 (/dev/dri/card1) property 'FB_ID' (17) to 0
libmutter-Message: 21:52:23.596: KMS: [atomic] Setting plane 52 (/dev/dri/card1) property 'CRTC_ID' (20) to 0
libmutter-Message: 21:52:23.596: KMS: [atomic] Committing update 1147, flags: ATOMIC_NONBLOCK|PAGE_FLIP_EVENT
libmutter-Message: 21:52:23.596: KMS: [atomic] KMS update failed: drmModeAtomicCommit: Invalid argument
libmutter-Message: 21:52:23.596: KMS: [atomic] Creating transient page flip data for (53, /dev/dri/card1): 0x25619f0
(gnome-shell:1346040): libmutter-WARNING **: 21:52:23.596: Failed to post KMS update: drmModeAtomicCommit: Invalid argument
(gnome-shell:1346040): libmutter-WARNING **: 21:52:23.596: Page flip discarded: drmModeAtomicCommit: Invalid argument