4 files changed, 45 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index d2b68505f088..ff6eb93337e0 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1618,6 +1618,8 @@ struct intel_psr {
 	u32 dc3co_exit_delay;
 	struct delayed_work dc3co_work;
 	u8 entry_setup_frames;
+
+	bool link_ok;
 };
 
 struct intel_dp {
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 5fbb33bd6bb1..ff5ba7b3035f 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5038,7 +5038,8 @@ intel_dp_needs_link_retrain(struct intel_dp *intel_dp)
 		return true;
 
 	/* Retrain if link not ok */
-	return !intel_dp_link_ok(intel_dp, link_status);
+	return !intel_dp_link_ok(intel_dp, link_status) &&
+		!intel_psr_link_ok(intel_dp);
 }
 
 bool intel_dp_has_connector(struct intel_dp *intel_dp,
diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
index 0c8da1701c3a..a784c0b81556 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.c
+++ b/drivers/gpu/drm/i915/display/intel_psr.c
@@ -2013,6 +2013,15 @@ static void intel_psr_enable_locked(struct intel_dp *intel_dp,
 	intel_dp->psr.enabled = true;
 	intel_dp->psr.paused = false;
 
+	/*
+	 * Link_ok is sticky and set here on PSR enable. We can assume link
+	 * training is complete as we never continue to PSR enable with
+	 * untrained link. Link_ok is kept as set until first short pulse
+	 * interrupt. This is targeted to workaround panels stating bad link
+	 * after PSR is enabled.
+	 */
+	intel_dp->psr.link_ok = true;
+
 	intel_psr_activate(intel_dp);
 }
 
@@ -2172,6 +2181,8 @@ void intel_psr_disable(struct intel_dp *intel_dp,
 
 	intel_psr_disable_locked(intel_dp);
 
+	intel_dp->psr.link_ok = false;
+
 	mutex_unlock(&intel_dp->psr.lock);
 	cancel_work_sync(&intel_dp->psr.work);
 	cancel_delayed_work_sync(&intel_dp->psr.dc3co_work);
@@ -3462,6 +3473,8 @@ void intel_psr_short_pulse(struct intel_dp *intel_dp)
 
 	mutex_lock(&psr->lock);
 
+	psr->link_ok = false;
+
 	if (!psr->enabled)
 		goto exit;
 
@@ -3522,6 +3535,33 @@ bool intel_psr_enabled(struct intel_dp *intel_dp)
 }
 
 /**
+ * intel_psr_link_ok - return psr->link_ok
+ * @intel_dp: struct intel_dp
+ *
+ * We are seeing unexpected link re-trainings with some panels. This is caused
+ * by panel stating bad link status after PSR is enabled. Code checking link
+ * status can call this to ensure it can ignore bad link status stated by the
+ * panel I.e. if panel is stating bad link and intel_psr_link_ok is stating link
+ * is ok caller should rely on latter.
+ *
+ * Return value of link_ok
+ */
+bool intel_psr_link_ok(struct intel_dp *intel_dp)
+{
+	bool ret;
+
+	if ((!CAN_PSR(intel_dp) && !CAN_PANEL_REPLAY(intel_dp)) ||
+	    !intel_dp_is_edp(intel_dp))
+		return false;
+
+	mutex_lock(&intel_dp->psr.lock);
+	ret = intel_dp->psr.link_ok;
+	mutex_unlock(&intel_dp->psr.lock);
+
+	return ret;
+}
+
+/**
  * intel_psr_lock - grab PSR lock
  * @crtc_state: the crtc state
  *
diff --git a/drivers/gpu/drm/i915/display/intel_psr.h b/drivers/gpu/drm/i915/display/intel_psr.h
index 5f26f61f82aa..956be263c09e 100644
--- a/drivers/gpu/drm/i915/display/intel_psr.h
+++ b/drivers/gpu/drm/i915/display/intel_psr.h
@@ -59,6 +59,7 @@ void intel_psr2_program_trans_man_trk_ctl(const struct intel_crtc_state *crtc_st
 void intel_psr_pause(struct intel_dp *intel_dp);
 void intel_psr_resume(struct intel_dp *intel_dp);
 bool intel_psr_needs_block_dc_vblank(const struct intel_crtc_state *crtc_state);
+bool intel_psr_link_ok(struct intel_dp *intel_dp);
 
 void intel_psr_lock(const struct intel_crtc_state *crtc_state);
 void intel_psr_unlock(const struct intel_crtc_state *crtc_state);