drm/i915/dp: do not limit rate seek when not needed

In link training fallback, we're trying to find a rate that we know is
in a sorted array of common link rates. We don't need to limit the array
using the max rate. For test request, the DP CTS doesn't say we should
limit the rate based on earlier fallback. This lets us get rid of
intel_dp_link_rate_index() and use intel_dp_rate_index() instead.

Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/33cab481a3228f31e938b5891a6285d892dcf272.1491485983.git.jani.nikula@intel.com

drivers/gpu/drm/i915/intel_dp.c

@@ -317,25 +317,16 @@ static int intel_dp_common_len_rate_limit(struct intel_dp *intel_dp,
 	return 0;
 }
 
-static int intel_dp_link_rate_index(struct intel_dp *intel_dp, int link_rate)
-{
-	int common_len;
-
-	common_len = intel_dp_common_len_rate_limit(intel_dp,
-						    intel_dp->max_sink_link_rate);
-
-	return intel_dp_rate_index(intel_dp->common_rates, common_len, link_rate);
-}
-
 int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
 					    int link_rate, uint8_t lane_count)
 {
-	const int *common_rates = intel_dp->common_rates;
-	int link_rate_index;
+	int index;
 
-	link_rate_index = intel_dp_link_rate_index(intel_dp, link_rate);
-	if (link_rate_index > 0) {
-		intel_dp->max_sink_link_rate = common_rates[link_rate_index - 1];
+	index = intel_dp_rate_index(intel_dp->common_rates,
+				    intel_dp->num_common_rates,
+				    link_rate);
+	if (index > 0) {
+		intel_dp->max_sink_link_rate = intel_dp->common_rates[index - 1];
 		intel_dp->max_sink_lane_count = lane_count;
 	} else if (lane_count > 1) {
 		intel_dp->max_sink_link_rate = intel_dp_max_sink_rate(intel_dp);
@@ -1685,7 +1676,8 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 
 	/* Use values requested by Compliance Test Request */
 	if (intel_dp->compliance.test_type == DP_TEST_LINK_TRAINING) {
-		link_rate_index = intel_dp_link_rate_index(intel_dp,
+		link_rate_index = intel_dp_rate_index(intel_dp->common_rates,
+						      intel_dp->num_common_rates,
 						      intel_dp->compliance.test_link_rate);
 		if (link_rate_index >= 0)
 			min_clock = max_clock = link_rate_index;
@@ -3988,7 +3980,8 @@ static uint8_t intel_dp_autotest_link_training(struct intel_dp *intel_dp)
 	}
 	/* Validate the requested link rate */
 	test_link_rate = drm_dp_bw_code_to_link_rate(test_link_bw);
-	link_rate_index = intel_dp_link_rate_index(intel_dp,
+	link_rate_index = intel_dp_rate_index(intel_dp->common_rates,
+					      intel_dp->num_common_rates,
 					      test_link_rate);
 	if (link_rate_index < 0)
 		return DP_TEST_NAK;