diff -Nrup linux-4.4.143/include/drm/drm_dp_helper.h linux-4.4.189/include/drm/drm_dp_helper.h
--- linux-4.4.143/include/drm/drm_dp_helper.h	2018-07-22 05:25:54.000000000 -0700
+++ linux-4.4.189/include/drm/drm_dp_helper.h	2019-08-11 03:20:49.000000000 -0700
@@ -342,6 +342,7 @@
 # define DP_PSR_FRAME_CAPTURE		    (1 << 3)
 # define DP_PSR_SELECTIVE_UPDATE	    (1 << 4)
 # define DP_PSR_IRQ_HPD_WITH_CRC_ERRORS     (1 << 5)
+# define DP_PSR_ENABLE_PSR2		    (1 << 6) /* eDP 1.4a */
 
 #define DP_ADAPTER_CTRL			    0x1a0
 # define DP_ADAPTER_CTRL_FORCE_LOAD_SENSE   (1 << 0)