if_em.4freebsd

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Version: 361782 (ubuntu - 24/10/10)

Section: 4 (Pilotes et protocoles réseau)

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NAME

em - Intel(R) PRO/1000 Gigabit Ethernet adapter driver

SYNOPSIS

To compile this driver into the kernel, place the following line in your kernel configuration file:
device em

Alternatively, to load the driver as a module at boot time, place the following line in loader.conf5:

 if_em_load="YES"

DESCRIPTION

The driver provides support for PCI Gigabit Ethernet adapters based on the Intel 82540, 82541ER, 82541PI, 82542, 82543, 82544, 82545, 82546, 82546EB, 82546GB, 82547, 82571, 81572, 82573, and 82574 Ethernet controller chips. The driver supports Transmit/Receive checksum offload and Jumbo Frames on all but 82542-based adapters. Furthermore it supports TCP segmentation offload (TSO) on all adapters but those based on the 82543, 82544 and 82547 controller chips. For further hardware information, 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 Fx .

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.

This driver version supports VLANs. The 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 driver supports the following media options:

full-duplex
Forces full-duplex operation
half-duplex
Forces half-duplex operation.

Only use mediaopt to set the driver to full-duplex If mediaopt is not specified, the driver defaults to half-duplex

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

HARDWARE

The driver supports Gigabit Ethernet adapters based on the Intel 82540, 82541ER, 82541PI, 82542, 82543, 82544, 82545, 82546, 82546EB, 82546GB, 82547, 82571, 82572, 82573, and 82574 controller chips:

LOADER TUNABLES

Tunables can be set at the loader(8) prompt before booting the kernel or stored in loader.conf5.
hw.em.rxd
Number of receive descriptors allocated by the driver. The default value is 256. The 82542 and 82543-based adapters can handle up to 256 descriptors, while others can have up to 4096.
hw.em.txd
Number of transmit descriptors allocated by the driver. The default value is 256. The 82542 and 82543-based adapters can handle up to 256 descriptors, while others can have up to 4096.
hw.em.rx_int_delay
This value delays the generation of receive interrupts in units of 1.024 microseconds. The default value is 0, since adapters may hang with this feature being enabled.
hw.em.rx_abs_int_delay
If hw.em.rx_int_delay is non-zero, this tunable limits the maximum delay in which a receive interrupt is generated.
hw.em.tx_int_delay
This value delays the generation of transmit interrupts in units of 1.024 microseconds. The default value is 64.
hw.em.tx_abs_int_delay
If hw.em.tx_int_delay is non-zero, this tunable limits the maximum delay in which a transmit interrupt is generated.

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 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 Aq freebsdnic@mailbox.intel.com .

SEE ALSO

altq(4), arp(4), igb(4), netintro(4), ng_ether4, polling(4), vlan(4), ifconfig(8)

HISTORY

The device driver first appeared in Fx 4.4 .

AUTHORS

The driver was written by An Intel Corporation Aq freebsdnic@mailbox.intel.com .

BUGS

Hardware-assisted VLAN processing is disabled by default. You can enable it on an interface using ifconfig(8).