drm/i915: Release temporary load-detect state upon switching

After we call drm_atomic_commit() on the load-detect state, we can free
our local reference. Upon restore, we only apply and free the previous state.

Fixes: 0853695 ("drm: Add reference counting to drm_atomic_state")
Signed-off-by: Chris Wilson <[email protected]>
Cc: Chris Wilson <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: <[email protected]> # v4.10-rc1+
Link: http://patchwork.freedesktop.org/patch/msgid/[email protected]
Reviewed-by: Ville Syrjälä <[email protected]>
(cherry picked from commit 7abbd11)
Signed-off-by: Jani Nikula <[email protected]>

drivers/gpu/drm/i915/intel_display.c

@@ -11246,6 +11246,7 @@ bool intel_get_load_detect_pipe(struct drm_connector *connector,
 	}
 
 	old->restore_state = restore_state;
+	drm_atomic_state_put(state);
 
 	/* let the connector get through one full cycle before testing */
 	intel_wait_for_vblank(dev_priv, intel_crtc->pipe);