tail head cat sleep
QR code linking to this page

Manual Pages  — SK


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 loader.conf(5):



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 port.

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:


Tunables can be set at the loader(8) prompt before booting the kernel or stored in loader.conf(5).
  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) http://people.freebsd.org/~wpaul/SysKonnect/xmacii_datasheet_rev_c_9-29.pdf

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 <Mt wpaul@ctr.columbia.edu>.

SK (4) August 29, 2012

tail head cat sleep
QR code linking to this page

Please direct any comments about this manual page service to Ben Bullock. Privacy policy.

What will happen when the 32-bit Unix date goes negative in mid-January 2038 does not bear thinking about.
— Henry Spencer