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     sk — SysKonnect SK-984x and SK-982x PCI Gigabit Ethernet adapter driver


     To compile this driver into the kernel, place the following lines in your kernel
     configuration file:

           device miibus
           device sk

     Alternatively, to load the driver as a module at boot time, place the following line in



     The sk driver provides support for the SysKonnect SK-984x and SK-982x series PCI Gigabit
     Ethernet adapters.

     The SysKonnect adapters consist of two main components: the XaQti Corp.  XMAC II gigabit MAC
     and the SysKonnect GEnesis controller ASIC.  The XMAC provides the gigabit MAC and PHY
     support while the GEnesis provides an interface to the PCI bus, DMA support, packet
     buffering and arbitration.  The GEnesis can control up to two XMACs simultaneously, allowing
     dual-port NIC configurations.

     The SK-982x 1000baseT adapters also include a Broadcom BCM5400 1000baseTX PHY which is used
     in place of the XMAC's internal PHY.  The Broadcom PHY is connected to the XMAC via its GMII

     The sk driver configures dual port SysKonnect adapters such that each XMAC is treated as a
     separate logical network interface.  Both ports can operate independently of each other and
     can be connected to separate networks.  The SysKonnect driver software currently only uses
     the second port on dual port adapters for failover purposes: if the link on the primary port
     fails, the SysKonnect driver will automatically switch traffic onto the second port.

     Also supported is the Marvell Semiconductor 88E100* gigabit PHY.

     The XaQti XMAC II supports full and half duplex operation with autonegotiation.  The XMAC
     also supports unlimited frame sizes.  Support for jumbo frames is provided via the interface
     MTU setting.  Selecting an MTU larger than 1500 bytes with the ifconfig(8) utility
     configures the adapter to receive and transmit jumbo frames.  Using jumbo frames can greatly
     improve performance for certain tasks, such as file transfers and data streaming.

     The sk driver supports the following media types:

     autoselect            Enable autoselection of the media type and options.  The user can
                           manually override the autoselected mode by adding media options to the
                           /etc/rc.conf file.

     1000baseTX            Set 1000baseTX operation over twisted pair.  This is only available
                           for SK-982x series adapters with 1000baseT ports.  Both full-duplex
                           and half-duplex modes are supported.

     1000baseSX            Set 1000Mbps (Gigabit Ethernet) operation.  Both full-duplex and
                           half-duplex modes are supported.

     The sk driver supports the following media options:

     full-duplex           Force full duplex operation.

     half-duplex           Force half duplex operation.

     For more information on configuring this device, see ifconfig(8).


     Adapters supported by the sk driver include:

        3Com 3C940 single port, 1000baseT adapter
        3Com 3C2000-T single port, 1000baseT adapter
        Belkin F5D5005 single port, 1000baseT adapter
        D-Link DGE-530T single port, 1000baseT adapter
        Linksys (revision 2) single port, 1000baseT adapter
        SK-9521 SK-NET GE-T single port, 1000baseT adapter
        SK-9821 SK-NET GE-T single port, 1000baseT adapter
        SK-9822 SK-NET GE-T dual port, 1000baseT adapter
        SK-9841 SK-NET GE-LX single port, single mode fiber adapter
        SK-9842 SK-NET GE-LX dual port, single mode fiber adapter
        SK-9843 SK-NET GE-SX single port, multimode fiber adapter
        SK-9844 SK-NET GE-SX dual port, multimode fiber adapter
        SMC 9452TX single port, 1000baseT adapter


     Tunables can be set at the loader(8) prompt before booting the kernel or stored in

             Disable jumbo frame support.  Systems with less memory can set it to a non-zero
             value to save memory.  The default value is 0.


     The following variable is available as both sysctl(8) variable and loader(8) tunable:

             This variable controls interrupt moderation.  The accepted range is 10 to 10000.
             The default value is 100 microseconds.  The interface has to be brought down and up
             again before a change takes effect.


     sk%d: couldn't map memory  A fatal initialization error has occurred.

     sk%d: couldn't map ports  A fatal initialization error has occurred.

     sk%d: couldn't map interrupt  A fatal initialization error has occurred.

     sk%d: no memory for softc struct!  The driver failed to allocate memory for per-device
     instance information during initialization.

     sk%d: failed to enable memory mapping!  The driver failed to initialize PCI shared memory
     mapping.  This might happen if the card is not in a bus-master slot.

     sk%d: no memory for jumbo buffers!  The driver failed to allocate memory for jumbo frames
     during initialization.

     sk%d: watchdog timeout  The device has stopped responding to the network, or there is a
     problem with the network connection (cable).


     altq(4), arp(4), miibus(4), netintro(4), ng_ether(4), vlan(4), ifconfig(8)

     XaQti XMAC II datasheet,

     SysKonnect GEnesis programming manual,


     The sk device driver first appeared in FreeBSD 3.0.


     The sk driver was written by Bill Paul <>.