From: Harry Wentland <harry.wentland@amd.com>
Date: Wed, 21 Jun 2017 16:48:06 -0400
Subject: drm/amd/display: Don't program scaler if we have no surface
Git-commit: 866294f80582e252913c72b5e0f1792f6133424d
Patch-mainline: v4.15-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

If we don't have a surface in dc_commit_streams scl_data won't get
populated in resource_build_scaling_params_for_context. In this case we
shouldn't attempt to program the scaler.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
@@ -1099,10 +1099,12 @@ static enum dc_status apply_single_contr
 
 	pipe_ctx->scl_data.lb_params.alpha_en = pipe_ctx->bottom_pipe != 0;
 	/* program_scaler and allocate_mem_input are not new asic */
-	if (!pipe_ctx_old || memcmp(&pipe_ctx_old->scl_data,
-				&pipe_ctx->scl_data,
-				sizeof(struct scaler_data)) != 0)
+	if ((!pipe_ctx_old ||
+	     memcmp(&pipe_ctx_old->scl_data, &pipe_ctx->scl_data,
+		    sizeof(struct scaler_data)) != 0) &&
+	     pipe_ctx->surface) {
 		program_scaler(dc, pipe_ctx);
+	}
 
 	/* mst support - use total stream count */
 #if defined(CONFIG_DRM_AMD_DC_DCN1_0)