drm/amd/display: Enable double buffer when unblank crtc.

Signed-off-by: Yongqiang Sun <yongqiang.sun@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_timing_generator.c

@@ -289,6 +289,9 @@ static void tgn10_unblank_crtc(struct timing_generator *tg)
 {
 	struct dcn10_timing_generator *tgn10 = DCN10TG_FROM_TG(tg);
 
+	REG_UPDATE(OTG_DOUBLE_BUFFER_CONTROL,
+			OTG_BLANK_DATA_DOUBLE_BUFFER_EN, 1);
+
 	REG_UPDATE_2(OTG_BLANK_CONTROL,
 			OTG_BLANK_DATA_EN, 0,
 			OTG_BLANK_DE_MODE, 0);