return ret;
 }
 
+static void
+auxch_mux(struct nouveau_i2c_port *port)
+{
+       if (port->dcb & 0x00000100) {
+               u32 reg = 0x00e500 + (port->drive * 0x50);
+               /* nfi, but neither auxch or i2c work if it's 1 */
+               nv_mask(port->i2c, reg + 0x0c, 0x00000001, 0x00000000);
+               /* nfi, but switches auxch vs normal i2c */
+               nv_mask(port->i2c, reg + 0x00, 0x0000f003, 0x00002002);
+       }
+}
+
 int
 nv_rdaux(struct nouveau_i2c_port *auxch, u32 addr, u8 *data, u8 size)
 {
+       auxch_mux(auxch);
        return auxch_tx(auxch->i2c, auxch->drive, 9, addr, data, size);
 }
 
 int
 nv_wraux(struct nouveau_i2c_port *auxch, u32 addr, u8 *data, u8 size)
 {
+       auxch_mux(auxch);
        return auxch_tx(auxch->i2c, auxch->drive, 8, addr, data, size);
 }
 
        struct i2c_msg *msg = msgs;
        int ret, mcnt = num;
 
+       auxch_mux(auxch);
+
        while (mcnt--) {
                u8 remaining = msg->len;
                u8 *ptr = msg->buf;
 
 
        list_for_each_entry(port, &i2c->ports, head) {
                if (port->index == index)
-                       break;
-       }
-
-       if (&port->head == &i2c->ports)
-               return NULL;
-
-       if (nv_device(i2c)->card_type >= NV_50 && (port->dcb & 0x00000100)) {
-               u32 reg = 0x00e500, val;
-               if (port->type == 6) {
-                       reg += port->drive * 0x50;
-                       val  = 0x2002;
-               } else {
-                       reg += ((port->dcb & 0x1e00) >> 9) * 0x50;
-                       val  = 0xe001;
-               }
-
-               /* nfi, but neither auxch or i2c work if it's 1 */
-               nv_mask(i2c, reg + 0x0c, 0x00000001, 0x00000000);
-               /* nfi, but switches auxch vs normal i2c */
-               nv_mask(i2c, reg + 0x00, 0x0000f003, val);
+                       return port;
        }
 
-       return port;
+       return NULL;
 }
 
 static int
        return 0;
 }
 
+static int
+nouveau_i2c_pre_xfer(struct i2c_adapter *adap)
+{
+       struct nouveau_i2c_port *port = (void *)adap;
+       struct nouveau_i2c *i2c = port->i2c;
+
+       if (nv_device(i2c)->card_type >= NV_50 && (port->dcb & 0x00000100)) {
+               u32 reg = 0x00e500 + ((port->dcb & 0x1e00) >> 9) * 0x50;
+               /* nfi, but neither auxch or i2c work if it's 1 */
+               nv_mask(i2c, reg + 0x0c, 0x00000001, 0x00000000);
+               /* nfi, but switches auxch vs normal i2c */
+               nv_mask(i2c, reg + 0x00, 0x0000f003, 0x0000e001);
+       }
+
+       return 0;
+}
+
 static const u32 nv50_i2c_port[] = {
        0x00e138, 0x00e150, 0x00e168, 0x00e180,
        0x00e254, 0x00e274, 0x00e764, 0x00e780,
                                port->bit.setscl = nouveau_i2c_drive_scl;
                                port->bit.getsda = nouveau_i2c_sense_sda;
                                port->bit.getscl = nouveau_i2c_sense_scl;
+                               port->bit.pre_xfer = nouveau_i2c_pre_xfer;
                                ret = i2c_bit_add_bus(&port->adapter);
                        }
                } else {