20.10. Dynamically adding a qeth device

Procedure

1. Determine whether the qeth device driver modules are loaded. The following example shows loaded qeth modules:

   # lsmod | grep qeth
   qeth_l3                69632  0
   qeth_l2                49152  1
   qeth                  131072  2 qeth_l3,qeth_l2
   qdio                   65536  3 qeth,qeth_l3,qeth_l2
   ccwgroup               20480  1 qeth

   If the output of the lsmod command shows that the qeth modules are not loaded, run the modprobe command to load them:

   # modprobe qeth

2. Use the cio_ignore utility to remove the network channels from the list of ignored devices and make them visible to Linux:

   # cio_ignore -r read_device_bus_id,write_device_bus_id,data_device_bus_id

   Replace read_device_bus_id,write_device_bus_id,data_device_bus_id with the three device bus IDs representing a network device. For example, if the read_device_bus_id is 0.0.f500, the write_device_bus_id is 0.0.f501, and the data_device_bus_id is 0.0.f502:

   # cio_ignore -r 0.0.f500,0.0.f501,0.0.f502

3. Use the znetconf utility to sense and list candidate configurations for network devices:

   # znetconf -u
   Scanning for network devices...
   Device IDs                 Type    Card Type      CHPID Drv.
   ------------------------------------------------------------
   0.0.f500,0.0.f501,0.0.f502 1731/01 OSA (QDIO)        00 qeth
   0.0.f503,0.0.f504,0.0.f505 1731/01 OSA (QDIO)        01 qeth
   0.0.0400,0.0.0401,0.0.0402 1731/05 HiperSockets      02 qeth

4. Select the configuration you want to work with and use znetconf to apply the configuration and to bring the configured group device online as network device.

   # znetconf -a f500
   Scanning for network devices...
   Successfully configured device 0.0.f500 (encf500)

5. Optional: You can also pass arguments that are configured on the group device before it is set online:

   # znetconf -a f500 -o portname=myname
   Scanning for network devices...
   Successfully configured device 0.0.f500 (encf500)

   Now you can continue to configure the encf500 network interface. Alternatively, you can use sysfs attributes to set the device online as follows:

6. Create a qeth group device:

   # echo read_device_bus_id,write_device_bus_id,data_device_bus_id > /sys/bus/ccwgroup/drivers/qeth/group

   For example:

   # echo 0.0.f500,0.0.f501,0.0.f502 > /sys/bus/ccwgroup/drivers/qeth/group

7. Next, verify that the qeth group device was created properly by looking for the read channel:

   # ls /sys/bus/ccwgroup/drivers/qeth/0.0.f500

   You can optionally set additional parameters and features, depending on the way you are setting up your system and the features you require, such as:

   • portno
   • layer2
   • portname

8. Bring the device online by writing 1 to the online sysfs attribute:

   # echo 1 > /sys/bus/ccwgroup/drivers/qeth/0.0.f500/online

9. Then verify the state of the device:

   # cat /sys/bus/ccwgroup/drivers/qeth/0.0.f500/online
   											1

   A return value of 1 indicates that the device is online, while a return value 0 indicates that the device is offline.

10. Find the interface name that was assigned to the device:

    # cat /sys/bus/ccwgroup/drivers/qeth/0.0.f500/if_name
    encf500

    Now you can continue to configure the encf500 network interface.

    The following command from the s390utils package shows the most important settings of your qeth device:

    # lsqeth encf500
    Device name                     : encf500
    -------------------------------------------------
    card_type               : OSD_1000
    cdev0                   : 0.0.f500
    cdev1                   : 0.0.f501
    cdev2                   : 0.0.f502
    chpid                   : 76
    online                  : 1
    portname                : OSAPORT
    portno                  : 0
    state                   : UP (LAN ONLINE)
    priority_queueing       : always queue 0
    buffer_count            : 16
    layer2                  : 1
    isolation               : none