rx/tx -> x state on idle

gtxe2_channel/gtxe2_chnl_rx_oob.v

@@ -57,7 +57,7 @@ localparam wake_bursts_cnt = 5;
 localparam init_bursts_cnt = 5;
 
 wire    idle;
-assign  idle = RXN == RXP;
+assign  idle = (RXN == RXP) | (RXP === 1'bx);
 
 wire    state_notrans;
 wire    state_error; //nostrans substate

gtxe2_channel/gtxe2_chnl_tx.v

@@ -98,8 +98,8 @@ wire    line_idle_pcs; // line_idle in pcs clock domain
 wire    [internal_data_width - 1:0] ser_input;
 wire    oob_active;
 
-assign  TXP = ~line_idle & serial_data;
-assign  TXN = ~line_idle & ~serial_data;
+assign  TXP = ~line_idle ? serial_data : 1'bx;
+assign  TXN = ~line_idle ? ~serial_data : 1'bx;
 
 
 assign  line_idle_pcs = TXELECIDLE & ~oob_active | reset;