The patch below does not apply to the 4.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to [off-list ref].
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 00983519214b61c1b9371ec2ed55a4dde773e384 Mon Sep 17 00:00:00 2001
From: Mika Kahola <redacted>
Date: Wed, 20 Apr 2016 15:39:02 +0300
Subject: [PATCH] drm/i915: Fix eDP low vswing for Broadwell
MIME-Version: 1.0
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It was noticed on bug #94087 that module parameter
i915.edp_vswing=2 that should override the VBT setting
to use default voltage swing (400 mV) was not applied
for Broadwell.
This patch provides a fix for this by checking if default
i.e. higher voltage swing is requested to be used and
applies the DDI translations table for DP instead of eDP
(low vswing) table.
v2: Combine two if statements into one (Jani)
v3: Change dev_priv->edp_low_vswing to use dev_priv->vbt.edp.low_vswing
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94087
Signed-off-by: Mika Kahola <redacted>
Link: http://patchwork.freedesktop.org/patch/msgid/1461155942-7749-1-git-send-email-mika.kahola@intel.com
Cc: <redacted>
Signed-off-by: Ville Syrjälä <redacted>
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index c2348fbe9b70..a887b31cb684 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -443,9 +443,17 @@ void intel_prepare_ddi_buffer(struct intel_encoder *encoder)
} else if (IS_BROADWELL(dev_priv)) {
ddi_translations_fdi = bdw_ddi_translations_fdi;
ddi_translations_dp = bdw_ddi_translations_dp;
- ddi_translations_edp = bdw_ddi_translations_edp;
+
+ if (dev_priv->vbt.edp.low_vswing) {
+ ddi_translations_edp = bdw_ddi_translations_edp;
+ n_edp_entries = ARRAY_SIZE(bdw_ddi_translations_edp);
+ } else {
+ ddi_translations_edp = bdw_ddi_translations_dp;
+ n_edp_entries = ARRAY_SIZE(bdw_ddi_translations_dp);
+ }
+
ddi_translations_hdmi = bdw_ddi_translations_hdmi;
- n_edp_entries = ARRAY_SIZE(bdw_ddi_translations_edp);
+
n_dp_entries = ARRAY_SIZE(bdw_ddi_translations_dp);
n_hdmi_entries = ARRAY_SIZE(bdw_ddi_translations_hdmi);
hdmi_default_entry = 7;