| SK(4) | Device Drivers Manual | SK(4) | 
sk, skc,
  msk, mskc —
skc* at pci? dev ? function ?
sk* at skc?
mskc* at pci? dev ? function ?
msk* at mskc?
sk driver provides support for SysKonnect based
  Gigabit Ethernet adapters and Marvell based Gigabit Ethernet adapters,
  including the following:
The msk driver provides support for the
    Marvell Yukon-2 based Gigabit Ethernet adapters, including the
  following:
The SysKonnect based adapters consist of two main components: the
    XaQti Corp. XMAC II Gigabit MAC (sk) and the
    SysKonnect GEnesis controller ASIC (skc). 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 Marvell based adapters are a single integrated circuit, but
    are still presented as a separate MAC (sk) and
    controller ASIC (skc). At this time, there are no
    dual-port Marvell based NICs.
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.
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.
Hardware TCP/IP checksum offloading for IPv4 is available but not supported by the driver.
The following media types and options (as given to ifconfig(8)) are supported:
media
    autoselectmedia
    1000baseSX mediaopt
    full-duplexmedia
    1000baseSX mediaopt
    half-duplexmedia
    1000baseT mediaopt
    full-duplexFor more information on configuring this device, see
    ifconfig(8). To view a list
    of media types and options supported by the card, try
    ifconfig -m
    <device>. For example,
    ifconfig -m
    sk0.
XaQti XMAC II datasheet, http://www.xaqti.com.
SysKonnect GEnesis programming manual, http://www.syskonnect.com.
sk device driver first appeared in
  FreeBSD 3.0. OpenBSD support
  was added in OpenBSD 2.6.
  NetBSD support was added in NetBSD
  2.0.
The msk driver first appeared in
    OpenBSD 4.0, and was ported to
    NetBSD 4.0.
sk driver was written by Bill
  Paul
  <wpaul@ctr.columbia.edu>.
  Support for the Marvell Yukon-2 was added by Mark
  Kettenis
  <kettenis@openbsd.org>.
Performance with at least some Marvell-based adapters is poor, especially on loaded PCI buses or when the adapters are behind PCI-PCI bridges. It is believed that this is because the Marvell parts have significantly less buffering than the original SysKonnect cards had.
| January 9, 2018 | NetBSD 9.4 |