Revert "drm/i915/display: Re-add check for low voltage sku for max dp…

… source rate"

This reverts commit d592983.

With the Parade PS8461E MUX workaround (WaEdpLinkRateDataReload)
implemented we can get finally rid of the is_low_voltage_sku()
check that incorrectly prevents many machines from using the
8.1Gpbs link rate.

Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/5272
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/6323
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/6205
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220902070319.15395-2-ville.syrjala@linux.intel.com
Tested-by: Aaron Ma <aaron.ma@canonical.com>
Tested-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
(cherry picked from commit 483e3d8)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/i915/display/intel_dp.c

@@ -389,47 +389,21 @@ static int dg2_max_source_rate(struct intel_dp *intel_dp)
 	return intel_dp_is_edp(intel_dp) ? 810000 : 1350000;
 }
 
-static bool is_low_voltage_sku(struct drm_i915_private *i915, enum phy phy)
-{
-	u32 voltage;
-
-	voltage = intel_de_read(i915, ICL_PORT_COMP_DW3(phy)) & VOLTAGE_INFO_MASK;
-
-	return voltage == VOLTAGE_INFO_0_85V;
-}
-
 static int icl_max_source_rate(struct intel_dp *intel_dp)
 {
 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
 	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
 	enum phy phy = intel_port_to_phy(dev_priv, dig_port->base.port);
 
-	if (intel_phy_is_combo(dev_priv, phy) &&
-	    (is_low_voltage_sku(dev_priv, phy) || !intel_dp_is_edp(intel_dp)))
+	if (intel_phy_is_combo(dev_priv, phy) && !intel_dp_is_edp(intel_dp))
 		return 540000;
 
 	return 810000;
 }
 
 static int ehl_max_source_rate(struct intel_dp *intel_dp)
 {
-	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
-	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
-	enum phy phy = intel_port_to_phy(dev_priv, dig_port->base.port);
-
-	if (intel_dp_is_edp(intel_dp) || is_low_voltage_sku(dev_priv, phy))
-		return 540000;
-
-	return 810000;
-}
-
-static int dg1_max_source_rate(struct intel_dp *intel_dp)
-{
-	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
-	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
-	enum phy phy = intel_port_to_phy(i915, dig_port->base.port);
-
-	if (intel_phy_is_combo(i915, phy) && is_low_voltage_sku(i915, phy))
+	if (intel_dp_is_edp(intel_dp))
 		return 540000;
 
 	return 810000;
@@ -491,7 +465,7 @@ intel_dp_set_source_rates(struct intel_dp *intel_dp)
 			max_rate = dg2_max_source_rate(intel_dp);
 		else if (IS_ALDERLAKE_P(dev_priv) || IS_ALDERLAKE_S(dev_priv) ||
 			 IS_DG1(dev_priv) || IS_ROCKETLAKE(dev_priv))
-			max_rate = dg1_max_source_rate(intel_dp);
+			max_rate = 810000;
 		else if (IS_JSL_EHL(dev_priv))
 			max_rate = ehl_max_source_rate(intel_dp);
 		else