struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
        struct drm_device *dev = intel_dig_port->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
-       uint32_t ch_ctl = intel_dp->output_reg + 0x10;
+       uint32_t ch_ctl = intel_dp->aux_ch_ctl_reg;
        uint32_t status;
        bool done;
 
-       if (HAS_DDI(dev)) {
-               switch (intel_dig_port->port) {
-               case PORT_A:
-                       ch_ctl = DPA_AUX_CH_CTL;
-                       break;
-               case PORT_B:
-                       ch_ctl = PCH_DPB_AUX_CH_CTL;
-                       break;
-               case PORT_C:
-                       ch_ctl = PCH_DPC_AUX_CH_CTL;
-                       break;
-               case PORT_D:
-                       ch_ctl = PCH_DPD_AUX_CH_CTL;
-                       break;
-               default:
-                       BUG();
-               }
-       }
-
 #define C (((status = I915_READ_NOTRACE(ch_ctl)) & DP_AUX_CH_CTL_SEND_BUSY) == 0)
        if (has_aux_irq)
                done = wait_event_timeout(dev_priv->gmbus_wait_queue, C,
                uint8_t *send, int send_bytes,
                uint8_t *recv, int recv_size)
 {
-       uint32_t output_reg = intel_dp->output_reg;
        struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
        struct drm_device *dev = intel_dig_port->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
-       uint32_t ch_ctl = output_reg + 0x10;
+       uint32_t ch_ctl = intel_dp->aux_ch_ctl_reg;
        uint32_t ch_data = ch_ctl + 4;
        int i, ret, recv_bytes;
        uint32_t status;
         */
        pm_qos_update_request(&dev_priv->pm_qos, 0);
 
-       if (HAS_DDI(dev)) {
-               switch (intel_dig_port->port) {
-               case PORT_A:
-                       ch_ctl = DPA_AUX_CH_CTL;
-                       ch_data = DPA_AUX_CH_DATA1;
-                       break;
-               case PORT_B:
-                       ch_ctl = PCH_DPB_AUX_CH_CTL;
-                       ch_data = PCH_DPB_AUX_CH_DATA1;
-                       break;
-               case PORT_C:
-                       ch_ctl = PCH_DPC_AUX_CH_CTL;
-                       ch_data = PCH_DPC_AUX_CH_DATA1;
-                       break;
-               case PORT_D:
-                       ch_ctl = PCH_DPD_AUX_CH_CTL;
-                       ch_data = PCH_DPD_AUX_CH_DATA1;
-                       break;
-               default:
-                       BUG();
-               }
-       }
-
        intel_dp_check_edp(intel_dp);
        /* The clock divider is based off the hrawclk,
         * and would like to run at 2MHz. So, take the
        else
                intel_connector->get_hw_state = intel_connector_get_hw_state;
 
+       intel_dp->aux_ch_ctl_reg = intel_dp->output_reg + 0x10;
+       if (HAS_DDI(dev)) {
+               switch (intel_dig_port->port) {
+               case PORT_A:
+                       intel_dp->aux_ch_ctl_reg = DPA_AUX_CH_CTL;
+                       break;
+               case PORT_B:
+                       intel_dp->aux_ch_ctl_reg = PCH_DPB_AUX_CH_CTL;
+                       break;
+               case PORT_C:
+                       intel_dp->aux_ch_ctl_reg = PCH_DPC_AUX_CH_CTL;
+                       break;
+               case PORT_D:
+                       intel_dp->aux_ch_ctl_reg = PCH_DPD_AUX_CH_CTL;
+                       break;
+               default:
+                       BUG();
+               }
+       }
 
        /* Set up the DDC bus. */
        switch (port) {