EM(4)

NAME
em - Intel(R) PRO/1000 gigabit Ethernet driver for the FreeBSD operating system

SYNOPSIS
device em

DESCRIPTION
The em driver provides support for PCI gigabit Ethernet adapters based on the Intel 82540, 82541, 82542, 82543, 82544, 82545, 82546, and 82547 Ethernet controller chips. The driver does not support Transmit/Receive checksum offload and Jumbo Frames on 82542-based adapters. The Intel PRO/1000 PM Network Connection does not support jumbo frames. For a list of supported adapters, see the README included with the driver.

For questions related to hardware requirements, refer to the documentation supplied with your Intel PRO/1000 adapter. All hardware requirements listed apply to use with FreeBSD.

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. The maximum MTU size for Jumbo Frames is 16114. Some Intel gigabit adapters that support Jumbo Frames have a frame size limit of 9238 bytes, with a corresponding MTU size limit of 9216 bytes. The adapters with this limitation are based on the Intel 82571EB and 82572EI controllers.

This driver version supports VLANs. For information on enabling VLANs, see the README. The em driver supports the following media types:

autoselect
    Enables auto-negotiation for speed and duplex.

10baseT/UTP
    Sets 10Mbps operation. Use the mediaopt option to select full-duplex mode.

100baseTX
    Sets 100Mbps operation. Use the mediaopt option to select full-duplex mode.

1000baseSX
    Sets 1000Mbps operation. Only full-duplex mode is supported at this speed.

1000baseTX
    Sets 1000Mbps operation. Only full-duplex mode is supported at this speed.

The em driver supports both full-duplex and half-duplex. Use mediaopt to force the driver to either of these settings. Note that the only valid parameter for mediaopt is full-duplex; to force the driver to half-duplex when running at less than gibabit speed, leave mediaopt unspecifed.

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

DIAGNOSTICS

em%d: Unable to allocate bus resource: memory A fatal initialization error has occurred.

em%d: Unable to allocate bus resource: interrupt A fatal initialization error has occurred.

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

SUPPORT
For additional information regarding building and installation, see the README included with the driver. For general information and support, go to the Intel support website at: http://support.intel.com.

If an issue is identified with the released source code on the supported kernel with a supported adapter, email the specific information related to the issue to <freebsdnic@mailbox.intel.com>.

SEE ALSO
arp(4), gx(4), netintro(4), ng_ether(4), vlan(4), ifconfig(8)

HISTORY
The em device driver first appeared in FreeBSD 4.4.

AUTHORS
The em driver was written by Intel Corporation <freebsdnic@mailbox.intel.com>.