From 481435d032583b59d65d11ffca2cc5c16b8b0e4e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Tue, 12 May 2020 20:41:44 +0300
Subject: drm/i915: Fix DP_TRAIN_MAX_{PRE_EMPHASIS,SWING}_REACHED handling
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Git-commit: 3625a1f5bf6ba47fbd903be1d63dade9a48e8e72
Patch-mainline: v5.9-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322
The DP spec says:
"The transmitter shall support at least three levels of voltage
swing (Levels 0, 1, and 2).
If only three levels of voltage swing are supported (VOLTAGE
SWING SET field (bits 1:0) are programmed to 10 (Level 2)),
this bit shall be set to 1, and cleared in all other cases.
If all four levels of voltage swing are supported (VOLTAGE
SWING SET field (bits 1:0) are programmed to 11 (Level 3)),
this bit shall be set to 1,and cleared in all other cases."
Let's follow that exactly instead of the current apporach
where we can set those also for vswing/preemph levels 0 or 1
(or 2 when the platform max is 3).
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200512174145.3186-7-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/display/intel_dp_link_training.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
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 b9e4ee2dbddc..2493142a70e9 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -67,8 +67,9 @@ void intel_dp_get_adjust_train(struct intel_dp *intel_dp,
if (p >= preemph_max)
p = preemph_max | DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
- voltage_max = min(intel_dp->voltage_max(intel_dp),
- dp_voltage_max(p));
+ v = min(v, dp_voltage_max(p));
+
+ voltage_max = intel_dp->voltage_max(intel_dp);
if (v >= voltage_max)
v = voltage_max | DP_TRAIN_MAX_SWING_REACHED;
--
2.29.2