From: Ken Chalmers <ken.chalmers@amd.com>
Date: Wed, 20 Sep 2017 11:48:47 -0400
Subject: drm/amd/display: fix ASSERT() caused by missing registers.
Git-commit: 5df921d4c0e3e2065b961ac8d4269be68f80801d
Patch-mainline: v4.15-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Signed-off-by: Ken Chalmers <ken.chalmers@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>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c |   42 +++++++-------
 1 file changed, 23 insertions(+), 19 deletions(-)

--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
@@ -771,14 +771,16 @@ static void power_on_plane(
 	struct dce_hwseq *hws,
 	int plane_id)
 {
-	REG_SET(DC_IP_REQUEST_CNTL, 0,
-			IP_REQUEST_EN, 1);
-	dpp_pg_control(hws, plane_id, true);
-	hubp_pg_control(hws, plane_id, true);
-	REG_SET(DC_IP_REQUEST_CNTL, 0,
-			IP_REQUEST_EN, 0);
-	dm_logger_write(hws->ctx->logger, LOG_DEBUG,
-			"Un-gated front end for pipe %d\n", plane_id);
+	if (REG(DC_IP_REQUEST_CNTL)) {
+		REG_SET(DC_IP_REQUEST_CNTL, 0,
+				IP_REQUEST_EN, 1);
+		dpp_pg_control(hws, plane_id, true);
+		hubp_pg_control(hws, plane_id, true);
+		REG_SET(DC_IP_REQUEST_CNTL, 0,
+				IP_REQUEST_EN, 0);
+		dm_logger_write(hws->ctx->logger, LOG_DEBUG,
+				"Un-gated front end for pipe %d\n", plane_id);
+	}
 }
 
 static void undo_DEGVIDCN10_253_wa(struct dc *dc)
@@ -1130,18 +1132,20 @@ static void plane_atomic_power_down(stru
 	struct dce_hwseq *hws = dc->hwseq;
 	struct transform *xfm = dc->res_pool->transforms[fe_idx];
 
-	REG_SET(DC_IP_REQUEST_CNTL, 0,
-			IP_REQUEST_EN, 1);
-	dpp_pg_control(hws, fe_idx, false);
-	hubp_pg_control(hws, fe_idx, false);
-	xfm->funcs->transform_reset(xfm);
-	REG_SET(DC_IP_REQUEST_CNTL, 0,
-			IP_REQUEST_EN, 0);
-	dm_logger_write(dc->ctx->logger, LOG_DEBUG,
-			"Power gated front end %d\n", fe_idx);
+	if (REG(DC_IP_REQUEST_CNTL)) {
+		REG_SET(DC_IP_REQUEST_CNTL, 0,
+				IP_REQUEST_EN, 1);
+		dpp_pg_control(hws, fe_idx, false);
+		hubp_pg_control(hws, fe_idx, false);
+		xfm->funcs->transform_reset(xfm);
+		REG_SET(DC_IP_REQUEST_CNTL, 0,
+				IP_REQUEST_EN, 0);
+		dm_logger_write(dc->ctx->logger, LOG_DEBUG,
+				"Power gated front end %d\n", fe_idx);
 
-	if (dc->debug.sanity_checks)
-		verify_allow_pstate_change_high(dc->hwseq);
+		if (dc->debug.sanity_checks)
+			verify_allow_pstate_change_high(dc->hwseq);
+	}
 }