From f9776280c29e77a18cbc7ebb6d48f7885e494990 Mon Sep 17 00:00:00 2001
From: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Date: Thu, 27 Sep 2018 13:57:31 -0700
Subject: drm/i915/dp: Restrict link retrain workaround to external monitors
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Git-commit: f9776280c29e77a18cbc7ebb6d48f7885e494990
Patch-mainline: v4.20-rc1
References: bsc#1113956
Commit '3cf71bc9904d ("drm/i915: Re-apply "Perform link quality check,
unconditionally during long pulse"")' applies a work around for sinks
that don't signal link loss. The work around does not need to have to be
that broad as the issue was seen with only one particular monitor; limit
this only for external displays as eDP features like PSR turn off the link
and the driver ends up retraining the link seeeing that link is not
synchronized.
Cc: Lyude Paul <lyude@redhat.com>
Cc: Jan-Marek Glogowski <glogow@fbihome.de>
Cc: Ville Syrj채l채 <ville.syrjala@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
References: 3cf71bc9904d ("drm/i915: Re-apply "Perform link quality check, unconditionally during long pulse"")
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Ville Syrj채l채 <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180927205735.16651-2-dhinakaran.pandiyan@intel.com
(cherry picked from commit f24f6eb95807bca0dbd8dc5b2f3a4099000f4472)
Fixes: 399334708b4f ("drm/i915: Re-apply "Perform link quality check, unconditionally during long pulse"")
Cc: stable@vger.kernel.org
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
drivers/gpu/drm/i915/intel_dp.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index e2a1af0a3492..13f9b56a9ce7 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -5102,12 +5102,13 @@ intel_dp_long_pulse(struct intel_connector *connector,
*/
status = connector_status_disconnected;
goto out;
- } else {
- /*
- * Some external monitors do not signal loss of link
- * synchronization with an IRQ_HPD, so force a link status
- * check.
- */
+ }
+
+ /*
+ * Some external monitors do not signal loss of link synchronization
+ * with an IRQ_HPD, so force a link status check.
+ */
+ if (!intel_dp_is_edp(intel_dp)) {
struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
intel_dp_retrain_link(encoder, ctx);
--
2.20.1