DP_VOLTAGE_0_4
intel_dp->DP = DP_VOLTAGE_0_4 | DP_PRE_EMPHASIS_0;
signal_levels |= DP_VOLTAGE_0_4;
intel_dp->DP |= DP_VOLTAGE_0_4 | DP_PRE_EMPHASIS_0;
DP |= DP_VOLTAGE_0_4 | DP_PRE_EMPHASIS_0;