[PATCH] drm/i915: Calculate common rates and max lane count in Long pulse handler

[Manasi Navare <manasi.d.navare@intel.com>]

Supported link rate common to source and sink as well as the
maximum supported lane count based on source and sink capabilities should
be set only once on hotplug and then used anytime they are requested.
This patch creates and array of common rates and max lane count as the
intel_dp member. It gets calculated only once in the long pulse handler
and then gets used when requested in compute_config and other functions.

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c  | 38 ++++++++++++++++----------------------
 drivers/gpu/drm/i915/intel_drv.h |  5 +++++
 2 files changed, 21 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 9dfbde4..de37807 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -274,8 +274,7 @@ static int intersect_rates(const int *source_rates, int source_len,
 	return k;
 }
 
-static int intel_dp_common_rates(struct intel_dp *intel_dp,
-				 int *common_rates)
+static int intel_dp_common_rates(struct intel_dp *intel_dp)
 {
 	const int *source_rates, *sink_rates;
 	int source_len, sink_len;
@@ -285,7 +284,7 @@ static int intel_dp_common_rates(struct intel_dp *intel_dp,
 
 	return intersect_rates(source_rates, source_len,
 			       sink_rates, sink_len,
-			       common_rates);
+			       intel_dp->common_rates);
 }
 
 static enum drm_mode_status
@@ -312,7 +311,7 @@ static int intel_dp_common_rates(struct intel_dp *intel_dp,
 	}
 
 	max_link_clock = intel_dp_max_link_rate(intel_dp);
-	max_lanes = intel_dp_max_lane_count(intel_dp);
+	max_lanes = intel_dp->max_lane_count;
 
 	max_rate = intel_dp_max_data_rate(max_link_clock, max_lanes);
 	mode_rate = intel_dp_link_required(target_clock, 18);
@@ -1430,8 +1429,7 @@ static void snprintf_int_array(char *str, size_t len,
 static void intel_dp_print_rates(struct intel_dp *intel_dp)
 {
 	const int *source_rates, *sink_rates;
-	int source_len, sink_len, common_len;
-	int common_rates[DP_MAX_SUPPORTED_RATES];
+	int source_len, sink_len;
 	char str[128]; /* FIXME: too big for stack? */
 
 	if ((drm_debug & DRM_UT_KMS) == 0)
@@ -1445,8 +1443,8 @@ static void intel_dp_print_rates(struct intel_dp *intel_dp)
 	snprintf_int_array(str, sizeof(str), sink_rates, sink_len);
 	DRM_DEBUG_KMS("sink rates: %s\n", str);
 
-	common_len = intel_dp_common_rates(intel_dp, common_rates);
-	snprintf_int_array(str, sizeof(str), common_rates, common_len);
+	snprintf_int_array(str, sizeof(str), intel_dp->common_rates,
+			   intel_dp->common_len);
 	DRM_DEBUG_KMS("common rates: %s\n", str);
 }
 
@@ -1495,14 +1493,12 @@ static int rate_to_index(int find, const int *rates)
 int
 intel_dp_max_link_rate(struct intel_dp *intel_dp)
 {
-	int rates[DP_MAX_SUPPORTED_RATES] = {};
-	int len;
+	int len = intel_dp->common_len;
 
-	len = intel_dp_common_rates(intel_dp, rates);
 	if (WARN_ON(len <= 0))
 		return 162000;
 
-	return rates[len - 1];
+	return intel_dp->common_rates[len - 1];
 }
 
 int intel_dp_rate_select(struct intel_dp *intel_dp, int rate)
@@ -1550,22 +1546,18 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp,
 	struct intel_connector *intel_connector = intel_dp->attached_connector;
 	int lane_count, clock;
 	int min_lane_count = 1;
-	int max_lane_count = intel_dp_max_lane_count(intel_dp);
+	int max_lane_count = intel_dp->max_lane_count;
 	/* Conveniently, the link BW constants become indices with a shift...*/
 	int min_clock = 0;
 	int max_clock;
 	int bpp, mode_rate;
 	int link_avail, link_clock;
-	int common_rates[DP_MAX_SUPPORTED_RATES] = {};
-	int common_len;
 	uint8_t link_bw, rate_select;
 
-	common_len = intel_dp_common_rates(intel_dp, common_rates);
-
 	/* No common link rates between source and sink */
-	WARN_ON(common_len <= 0);
+	WARN_ON(intel_dp->common_len <= 0);
 
-	max_clock = common_len - 1;
+	max_clock = intel_dp->common_len - 1;
 
 	if (HAS_PCH_SPLIT(dev_priv) && !HAS_DDI(dev_priv) && port != PORT_A)
 		pipe_config->has_pch_encoder = true;
@@ -1597,7 +1589,7 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp,
 
 	DRM_DEBUG_KMS("DP link computation with max lane count %i "
 		      "max bw %d pixel clock %iKHz\n",
-		      max_lane_count, common_rates[max_clock],
+		      max_lane_count, intel_dp->common_rates[max_clock],
 		      adjusted_mode->crtc_clock);
 
 	/* Walk through all bpp values. Luckily they're all nicely spaced with 2
@@ -1633,7 +1625,7 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp,
 				lane_count <= max_lane_count;
 				lane_count <<= 1) {
 
-				link_clock = common_rates[clock];
+				link_clock = intel_dp->common_rates[clock];
 				link_avail = intel_dp_max_data_rate(link_clock,
 								    lane_count);
 
@@ -1663,7 +1655,7 @@ static int intel_dp_compute_bpp(struct intel_dp *intel_dp,
 	pipe_config->lane_count = lane_count;
 
 	pipe_config->pipe_bpp = bpp;
-	pipe_config->port_clock = common_rates[clock];
+	pipe_config->port_clock = intel_dp->common_rates[clock];
 
 	intel_dp_compute_rate(intel_dp, pipe_config->port_clock,
 			      &link_bw, &rate_select);
@@ -4400,7 +4392,9 @@ static bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
 		      yesno(intel_dp_source_supports_hbr2(intel_dp)),
 		      yesno(drm_dp_tps3_supported(intel_dp->dpcd)));
 
+	intel_dp->common_len = intel_dp_common_rates(intel_dp);
 	intel_dp_print_rates(intel_dp);
+	intel_dp->max_lane_count = intel_dp_max_lane_count(intel_dp);
 
 	intel_dp_read_desc(intel_dp);
 
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 1d126c2..7c8885e 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -906,6 +906,11 @@ struct intel_dp {
 	/* sink rates as reported by DP_SUPPORTED_LINK_RATES */
 	uint8_t num_sink_rates;
 	int sink_rates[DP_MAX_SUPPORTED_RATES];
+	/* supported link rates common between source and sink */
+	int common_rates[DP_MAX_SUPPORTED_RATES];
+	int common_len;
+	/* Maximum supported lane count common between source and sink */
+	uint8_t max_lane_count;
 	/* sink or branch descriptor */
 	struct intel_dp_desc desc;
 	struct drm_dp_aux aux;
-- 
1.9.1

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