Re: [PATCH v3 3/9] drm/i915/dp: Move vswing/pre-emphasis adjustment calculation

"Manna, Animesh" <animesh.manna@xxxxxxxxx> · Thu, 2 Jan 2020 15:56:09 +0530

On 02-01-2020 14:48, Jani Nikula wrote:
On Mon, 30 Dec 2019, Animesh Manna <animesh.manna@xxxxxxxxx> wrote:
vswing/pre-emphasis adjustment calculation is needed in processing
of auto phy compliance request other than link training, so moved
the same function in intel_dp.c.
I guess I'm still asking why you think this is better located in
intel_dp.c than intel_dp_link_training.c, as the function has been moved
once in the other direction already to split out stuff from intel_dp.c
and to make the file smaller. Even the file name suggests it should
really be in intel_dp_link_training.c, right?

Just a thought, can we change the name to "intel_dp_link_config.c" from "intel_dp_link_training.c" which will provide little wider scope
and all the function playing with link configuration can be under it and also exposed through header file.

AFAIK, processing phy compliance request always do not need link training. I understood link training is very specific process consisting of clock recovery + channel eq.
So I am afraid of exposing intel_get_adjust_train() from intel_dp_link_training.c which is not only specific to link-training. Need your suggestion.

Regards,
Animesh


BR,
Jani.


No functional change.

v1: initial patch.
v2:
- used "intel_dp" prefix in function name. (Jani)
- used array notation instead pointer for link_status. (Ville)

Signed-off-by: Animesh Manna <animesh.manna@xxxxxxxxx>
---
  drivers/gpu/drm/i915/display/intel_dp.c       | 34 ++++++++++++++++++
  drivers/gpu/drm/i915/display/intel_dp.h       |  4 +++
  .../drm/i915/display/intel_dp_link_training.c | 36 ++-----------------
  3 files changed, 40 insertions(+), 34 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 991f343579ef..2a27ee106089 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -4110,6 +4110,40 @@ ivb_cpu_edp_signal_levels(u8 train_set)
  	}
  }
  
+void
+intel_dp_get_adjust_train(struct intel_dp *intel_dp,
+			  const u8 link_status[DP_LINK_STATUS_SIZE])
+{
+	u8 v = 0;
+	u8 p = 0;
+	int lane;
+	u8 voltage_max;
+	u8 preemph_max;
+
+	for (lane = 0; lane < intel_dp->lane_count; lane++) {
+		u8 this_v = drm_dp_get_adjust_request_voltage(link_status,
+							      lane);
+		u8 this_p = drm_dp_get_adjust_request_pre_emphasis(link_status,
+								   lane);
+
+		if (this_v > v)
+			v = this_v;
+		if (this_p > p)
+			p = this_p;
+	}
+
+	voltage_max = intel_dp_voltage_max(intel_dp);
+	if (v >= voltage_max)
+		v = voltage_max | DP_TRAIN_MAX_SWING_REACHED;
+
+	preemph_max = intel_dp_pre_emphasis_max(intel_dp, v);
+	if (p >= preemph_max)
+		p = preemph_max | DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
+
+	for (lane = 0; lane < 4; lane++)
+		intel_dp->train_set[lane] = v | p;
+}
+
  void
  intel_dp_set_signal_levels(struct intel_dp *intel_dp)
  {
diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
index 3da166054788..83eadc87af26 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.h
+++ b/drivers/gpu/drm/i915/display/intel_dp.h
@@ -9,6 +9,7 @@
  #include <linux/types.h>
  
  #include <drm/i915_drm.h>
+#include <drm/drm_dp_helper.h>
  
  #include "i915_reg.h"
  
@@ -91,6 +92,9 @@ void
  intel_dp_program_link_training_pattern(struct intel_dp *intel_dp,
  				       u8 dp_train_pat);
  void
+intel_dp_get_adjust_train(struct intel_dp *intel_dp,
+			  const u8 link_status[DP_LINK_STATUS_SIZE]);
+void
  intel_dp_set_signal_levels(struct intel_dp *intel_dp);
  void intel_dp_set_idle_link_train(struct intel_dp *intel_dp);
  u8
diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index 2a1130dd1ad0..e8ff9e279800 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -34,38 +34,6 @@ intel_dp_dump_link_status(const u8 link_status[DP_LINK_STATUS_SIZE])
  		      link_status[3], link_status[4], link_status[5]);
  }
  
-static void
-intel_get_adjust_train(struct intel_dp *intel_dp,
-		       const u8 link_status[DP_LINK_STATUS_SIZE])
-{
-	u8 v = 0;
-	u8 p = 0;
-	int lane;
-	u8 voltage_max;
-	u8 preemph_max;
-
-	for (lane = 0; lane < intel_dp->lane_count; lane++) {
-		u8 this_v = drm_dp_get_adjust_request_voltage(link_status, lane);
-		u8 this_p = drm_dp_get_adjust_request_pre_emphasis(link_status, lane);
-
-		if (this_v > v)
-			v = this_v;
-		if (this_p > p)
-			p = this_p;
-	}
-
-	voltage_max = intel_dp_voltage_max(intel_dp);
-	if (v >= voltage_max)
-		v = voltage_max | DP_TRAIN_MAX_SWING_REACHED;
-
-	preemph_max = intel_dp_pre_emphasis_max(intel_dp, v);
-	if (p >= preemph_max)
-		p = preemph_max | DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
-
-	for (lane = 0; lane < 4; lane++)
-		intel_dp->train_set[lane] = v | p;
-}
-
  static bool
  intel_dp_set_link_train(struct intel_dp *intel_dp,
  			u8 dp_train_pat)
@@ -215,7 +183,7 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
  		voltage = intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
  
  		/* Update training set as requested by target */
-		intel_get_adjust_train(intel_dp, link_status);
+		intel_dp_get_adjust_train(intel_dp, link_status);
  		if (!intel_dp_update_link_train(intel_dp)) {
  			DRM_ERROR("failed to update link training\n");
  			return false;
@@ -325,7 +293,7 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
  		}
  
  		/* Update training set as requested by target */
-		intel_get_adjust_train(intel_dp, link_status);
+		intel_dp_get_adjust_train(intel_dp, link_status);
  		if (!intel_dp_update_link_train(intel_dp)) {
  			DRM_ERROR("failed to update link training\n");
  			break;
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx






