From: Yongqiang Sun <yongqiang.sun@amd.com>
Date: Fri, 2 Feb 2018 17:35:00 -0500
Subject: drm/amd/display: Keep eDP stream enabled during boot.
Git-commit: 4cac1e6d2ffaddcdd054abf73c3a3c30eb659099
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

This path fixed specific eDP panel cold boot black screen
due to unnecessary enable link.
Change:
In case of boot up with eDP, if OS is going to set mode
on eDP, keep eDP light up, do not disable and reset corresponding
HW.
This change may affect dce asics and S3/S4 Resume with multi-monitor.

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>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link.c               |   11 ++
 drivers/gpu/drm/amd/display/dc/dc.h                         |    2 
 drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c |   45 +++++-------
 3 files changed, 34 insertions(+), 24 deletions(-)

--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -2296,7 +2296,16 @@ void core_link_enable_stream(
 {
 	struct dc  *core_dc = pipe_ctx->stream->ctx->dc;
 
-	enum dc_status status = enable_link(state, pipe_ctx);
+	enum dc_status status;
+
+	/* eDP lit up by bios already, no need to enable again. */
+	if (pipe_ctx->stream->signal == SIGNAL_TYPE_EDP &&
+		core_dc->apply_edp_fast_boot_optimization) {
+		core_dc->apply_edp_fast_boot_optimization = false;
+		return;
+	}
+
+	status = enable_link(state, pipe_ctx);
 
 	if (status != DC_OK) {
 			dm_logger_write(pipe_ctx->stream->ctx->logger,
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -257,6 +257,8 @@ struct dc {
 
 	bool optimized_required;
 
+	bool apply_edp_fast_boot_optimization;
+
 	/* FBC compressor */
 #if defined(CONFIG_DRM_AMD_DC_FBC)
 	struct compressor *fbc_compressor;
--- a/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
@@ -57,6 +57,8 @@
 #include "dce/dce_11_0_sh_mask.h"
 #include "custom_float.h"
 
+#include "atomfirmware.h"
+
 /*
  * All values are in milliseconds;
  * For eDP, after power-up/power/down,
@@ -1428,23 +1430,6 @@ static void disable_vga_and_power_gate_a
 	}
 }
 
-static struct dc_link *get_link_for_edp(
-		struct dc *dc)
-{
-	int i;
-	struct dc_link *link = NULL;
-
-	/* check if there is an eDP panel not in use */
-	for (i = 0; i < dc->link_count; i++) {
-		if (dc->links[i]->local_sink &&
-			dc->links[i]->local_sink->sink_signal == SIGNAL_TYPE_EDP) {
-			link = dc->links[i];
-			break;
-		}
-	}
-
-	return link;
-}
 static struct dc_link *get_link_for_edp_not_in_use(
 		struct dc *dc,
 		struct dc_state *context)
@@ -1480,13 +1465,27 @@ static struct dc_link *get_link_for_edp_
 void dce110_enable_accelerated_mode(struct dc *dc, struct dc_state *context)
 {
 	struct dc_bios *dcb = dc->ctx->dc_bios;
-	struct dc_link *edp_link_to_turnoff = get_link_for_edp_not_in_use(dc, context);
 
-	struct dc_link *edp_link = get_link_for_edp(dc);
-	if (dcb->funcs->get_vga_enabled_displays(dc->ctx->dc_bios) != 0) {
-		if (edp_link) {
-			/*we need turn off backlight before DP_blank and encoder powered down, todo add optimization*/
-			dc->hwss.edp_backlight_control(edp_link, false);
+	/* vbios already light up eDP, so we can leverage vbios and skip eDP
+	 * programming
+	 */
+	bool can_eDP_fast_boot_optimize =
+			(dcb->funcs->get_vga_enabled_displays(dc->ctx->dc_bios) == ATOM_DISPLAY_LCD1_ACTIVE);
+
+	/* if OS doesn't light up eDP and eDP link is available, we want to disable */
+	struct dc_link *edp_link_to_turnoff = NULL;
+
+	if (can_eDP_fast_boot_optimize) {
+		edp_link_to_turnoff = get_link_for_edp_not_in_use(dc, context);
+
+		if (!edp_link_to_turnoff)
+			dc->apply_edp_fast_boot_optimization = true;
+	}
+
+	if (!dc->apply_edp_fast_boot_optimization) {
+		if (edp_link_to_turnoff) {
+			/*turn off backlight before DP_blank and encoder powered down*/
+			dc->hwss.edp_backlight_control(edp_link_to_turnoff, false);
 		}
 		/*resume from S3, no vbios posting, no need to power down again*/
 		power_down_all_hw_blocks(dc);