[PATCH v2 23/28] drm/i915/dp_link_caps: Add helper to reset max link limits

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

Add a helper to reset the link_caps::max_limits max link limits to the
maximum common supported rate and lane count.

This is needed by a follow-up change in the link training fallback code,
which temporarily resets max_limits before searching for a fallback
configuration.

Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 .../gpu/drm/i915/display/intel_dp_link_caps.c | 22 +++++++++++++++++++
 .../gpu/drm/i915/display/intel_dp_link_caps.h |  1 +
 2 files changed, 23 insertions(+)

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 e568f00720d31..ae10200bdd934 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_caps.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_caps.c
@@ -160,6 +160,16 @@ static void set_max_link_limits_no_update(struct intel_dp_link_caps *link_caps,
 	intel_dp->link.max_lane_count = max_link_limits->lane_count;
 }
 
+static void reset_max_link_limits_no_update(struct intel_dp_link_caps *link_caps)
+{
+	struct intel_dp_link_config max_link_limits = {
+		.rate = intel_dp_max_common_rate(link_caps->dp),
+		.lane_count = intel_dp_link_caps_max_common_lane_count(link_caps),
+	};
+
+	set_max_link_limits_no_update(link_caps, &max_link_limits);
+}
+
 /**
  * intel_dp_link_caps_get_max_limits - get the current maximum link limits
  * @link_caps: link capabilities state
@@ -216,6 +226,18 @@ bool intel_dp_link_caps_set_max_limits(struct intel_dp_link_caps *link_caps,
 	return true;
 }
 
+/**
+ * intel_dp_link_caps_reset_max_limits - reset the current maximum link limits
+ * @link_caps: link capabilities state
+ *
+ * Reset the current maximum link limits to the maximum supported common link
+ * rate and lane count.
+ */
+void intel_dp_link_caps_reset_max_limits(struct intel_dp_link_caps *link_caps)
+{
+	reset_max_link_limits_no_update(link_caps);
+}
+
 static int intel_dp_link_config_bw(struct intel_dp *intel_dp,
 				   const struct intel_dp_link_config_entry *lc)
 {
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 c6c60b7888874..7baeb4359d2d4 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_caps.h
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_caps.h
@@ -31,6 +31,7 @@ void intel_dp_link_caps_get_max_limits(struct intel_dp_link_caps *link_caps,
 				       struct intel_dp_link_config *max_link_limits);
 bool intel_dp_link_caps_set_max_limits(struct intel_dp_link_caps *link_caps,
 				       const struct intel_dp_link_config *max_link_limits);
+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);
-- 
2.49.1