drm/amd/display: Explicitly disable cursor when disabling CRTC

[why]
On DCE, the cursor is not being disabled on commits where there is no
CRTC or FB enabled.

[how]
Explicitly disable the cursor in the commit tail only if the pending
commit disables the CRTC.
Signed-off-by: Victor Lu <victorchengchi.lu@amd.com>
Acked-by: Bindu Ramamurthy <bindu.r@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -8049,6 +8049,16 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
 			new_crtc_state->active_changed,
 			new_crtc_state->connectors_changed);
 
+		/* Disable cursor if disabling crtc */
+		if (old_crtc_state->active && !new_crtc_state->active) {
+			struct dc_cursor_position position;
+
+			memset(&position, 0, sizeof(position));
+			mutex_lock(&dm->dc_lock);
+			dc_stream_set_cursor_position(dm_old_crtc_state->stream, &position);
+			mutex_unlock(&dm->dc_lock);
+		}
+
 		/* Copy all transient state flags into dc state */
 		if (dm_new_crtc_state->stream) {
 			amdgpu_dm_crtc_copy_transient_flags(&dm_new_crtc_state->base,