From 540b0b7fe915858870be6cfe0fecd1fa85ccb4d6 Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula@intel.com>
Date: Thu, 6 Apr 2017 16:44:13 +0300
Subject: [PATCH] drm/i915/dp: add functions for max common link rate and lane count
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Git-commit: 540b0b7fe915858870be6cfe0fecd1fa85ccb4d6
Patch-mainline: v4.13-rc1
References: FATE#322643 bsc#1055900

These are the theoretical maximums common for source and sink. These are
the maximums we should start with. They may be degraded in case of link
training failures, and the dynamic link values are stored separately.

Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/5088aca253c47dfa18251e1adb976aca1718f083.1491485983.git.jani.nikula@intel.com
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/i915/intel_dp.c |   29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -161,22 +161,27 @@ static void intel_dp_set_sink_rates(stru
 	intel_dp->num_sink_rates = num_rates;
 }
 
-static int intel_dp_max_sink_rate(struct intel_dp *intel_dp)
+/* Theoretical max between source and sink */
+static int intel_dp_max_common_rate(struct intel_dp *intel_dp)
 {
-	return intel_dp->sink_rates[intel_dp->num_sink_rates - 1];
+	return intel_dp->common_rates[intel_dp->num_common_rates - 1];
 }
 
-static u8 intel_dp_max_lane_count(struct intel_dp *intel_dp)
+/* Theoretical max between source and sink */
+static int intel_dp_max_common_lane_count(struct intel_dp *intel_dp)
 {
 	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
-	u8 source_max, sink_max;
-
-	source_max = intel_dig_port->max_lanes;
-	sink_max = intel_dp->max_link_lane_count;
+	int source_max = intel_dig_port->max_lanes;
+	int sink_max = drm_dp_max_lane_count(intel_dp->dpcd);
 
 	return min(source_max, sink_max);
 }
 
+static int intel_dp_max_lane_count(struct intel_dp *intel_dp)
+{
+	return intel_dp->max_link_lane_count;
+}
+
 int
 intel_dp_link_required(int pixel_clock, int bpp)
 {
@@ -329,7 +334,7 @@ int intel_dp_get_link_train_fallback_val
 		intel_dp->max_link_rate = intel_dp->common_rates[index - 1];
 		intel_dp->max_link_lane_count = lane_count;
 	} else if (lane_count > 1) {
-		intel_dp->max_link_rate = intel_dp_max_sink_rate(intel_dp);
+		intel_dp->max_link_rate = intel_dp_max_common_rate(intel_dp);
 		intel_dp->max_link_lane_count = lane_count >> 1;
 	} else {
 		DRM_ERROR("Link Training Unsuccessful\n");
@@ -4612,11 +4617,11 @@ intel_dp_long_pulse(struct intel_connect
 		      yesno(drm_dp_tps3_supported(intel_dp->dpcd)));
 
 	if (intel_dp->reset_link_params) {
-		/* Set the max lane count for link */
-		intel_dp->max_link_lane_count = drm_dp_max_lane_count(intel_dp->dpcd);
+		/* Initial max link lane count */
+		intel_dp->max_link_lane_count = intel_dp_max_common_lane_count(intel_dp);
 
-		/* Set the max link rate for link */
-		intel_dp->max_link_rate = intel_dp_max_sink_rate(intel_dp);
+		/* Initial max link rate */
+		intel_dp->max_link_rate = intel_dp_max_common_rate(intel_dp);
 
 		intel_dp->reset_link_params = false;
 	}