[PATCH v2 24/28] drm/i915/dp_link_caps: Add helper to reset link_caps state

[Imre Deak <imre.deak@intel.com>]

Add a helper to reset the link_caps state, removing all restrictions
except user-forced parameters, re-allowing all supported
configurations. Currently this only resets the maximum link limits,
but follow-up changes will also re-enable configurations previously
disabled on a per-configuration basis by fallback or other logic.

Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c        |  3 +--
 .../gpu/drm/i915/display/intel_dp_link_caps.c  | 18 ++++++++++++++++++
 .../gpu/drm/i915/display/intel_dp_link_caps.h  |  1 +
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 3b3c31122452d..b63c6f047f83a 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -3610,8 +3610,7 @@ void intel_dp_set_link_params(struct intel_dp *intel_dp,
 
 void intel_dp_reset_link_params(struct intel_dp *intel_dp)
 {
-	intel_dp->link.max_lane_count = intel_dp_link_caps_max_common_lane_count(intel_dp->link.caps);
-	intel_dp->link.max_rate = intel_dp_max_common_rate(intel_dp);
+	intel_dp_link_caps_reset(intel_dp->link.caps);
 	intel_dp->link.mst_probed_lane_count = 0;
 	intel_dp->link.mst_probed_rate = 0;
 	intel_dp_link_training_reset(intel_dp->link.training);
diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_caps.c b/drivers/gpu/drm/i915/display/intel_dp_link_caps.c
index ae10200bdd934..9b7da5a64ee25 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_caps.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_caps.c
@@ -351,6 +351,24 @@ int intel_dp_link_config_index(struct intel_dp *intel_dp, int link_rate, int lan
 	return -1;
 }
 
+/**
+ * intel_dp_link_caps_reset - reset link capability restrictions
+ * @link_caps: link capabilities state
+ *
+ * Reset all current restrictions except for the user requested forced
+ * parameters, thus updating the set of allowed configurations and the
+ * derived maximum link information accordingly.
+ *
+ * This function is regularly called after a sink is connected, either
+ * for the first time to the connector or after a previous sink was
+ * disconnected from it, and intel_dp_link_caps_update() was called.
+ */
+void intel_dp_link_caps_reset(struct intel_dp_link_caps *link_caps)
+{
+	/* TODO: Update the maximum link information. */
+	reset_max_link_limits_no_update(link_caps);
+}
+
 static int i915_dp_force_link_rate_show(struct seq_file *m, void *data)
 {
 	struct intel_connector *connector = to_intel_connector(m->private);
diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_caps.h b/drivers/gpu/drm/i915/display/intel_dp_link_caps.h
index 7baeb4359d2d4..fa45a46723059 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_caps.h
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_caps.h
@@ -35,6 +35,7 @@ void intel_dp_link_caps_reset_max_limits(struct intel_dp_link_caps *link_caps);
 
 bool intel_dp_link_caps_update(struct intel_dp *intel_dp,
 			       const int *rates, int num_rates, int max_lane_count);
+void intel_dp_link_caps_reset(struct intel_dp_link_caps *link_caps);
 
 void intel_dp_link_caps_debugfs_add(struct intel_connector *connector);
 
-- 
2.49.1