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EM(4)			    Kernel Interfaces Manual			 EM(4)

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

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

	     device iflib
	     device em

       Alternatively, to load the driver as a module at	boot time,  place  the
       following line in loader.conf(5):

	     if_em_load="YES"

DESCRIPTION
       The  em driver provides support for PCI/PCI-X Gigabit Ethernet adapters
       based on	the Intel 82540, 82541ER, 82541PI, 82542, 82543, 82544,	82545,
       82546, 82546EB, 82546GB,	and 82547 controller chips.

       The em  driver  provides	 support  for  PCI  Express  Gigabit  Ethernet
       adapters	 based on the Intel 82571, 82572, 82573, 82574,	and 82583 Eth-
       ernet controller	chips.

       The em driver provides support for Gigabit Ethernet adapters  connected
       to I/O Controller Hub (ICH) and Platform	Controller Hub (PCH) including
       Intel  80003ES2LAN,  82562,  82566,  82567,  82577, 82578, 82579, i217,
       i218, and i219.

       The em  driver  provides	 support  for  PCI  Express  Gigabit  Ethernet
       adapters	 based on the Intel 82575, 82576, 82580, i210, i211, and i35x.
       These appear as igb interfaces to maintain compatibility	with  existing
       infrastructure.

       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 82542, 82543, 82544 and 82547 controller	chips.
       The identification LEDs of the adapters supported by the	em driver  can
       be  controlled  via the led(4) API for localization purposes.  For fur-
       ther hardware information, see the README included with the driver.

       For questions related to	hardware requirements, refer to	the documenta-
       tion supplied with your Intel PRO/1000 adapter.	All hardware  require-
       ments 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 maxi-
       mum MTU size for	Jumbo Frames is	16114.

       This  driver  supports hardware assisted	VLANs.	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 sup-
		    ported at this speed.

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

       The em 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  em	driver	supports  Gigabit Ethernet adapters based on the Intel
       82540, 82541ER, 82541PI,	82542, 82543, 82544,  82545,  82546,  82546EB,
       82546GB,	 82547,	 82571,	 82572,	 82573,	82574, 82575, 82576, and 82580
       controller chips:

       o   Intel Gigabit ET Dual Port Server Adapter (82576)
       o   Intel Gigabit VT Quad Port Server Adapter (82575)
       o   Intel Single, Dual and Quad Gigabit Ethernet	Controller (82580)
       o   Intel i210 and i211 Gigabit Ethernet	Controller
       o   Intel i350 and i354 Gigabit Ethernet	Controller
       o   Intel PRO/1000 CT Network Connection	(82547)
       o   Intel PRO/1000 F Server Adapter (82543)
       o   Intel PRO/1000 Gigabit Server Adapter (82542)
       o   Intel PRO/1000 GT Desktop Adapter (82541PI)
       o   Intel PRO/1000 MF Dual Port Server Adapter (82546)
       o   Intel PRO/1000 MF Server Adapter (82545)
       o   Intel PRO/1000 MF Server Adapter (LX) (82545)
       o   Intel PRO/1000 MT Desktop Adapter (82540)
       o   Intel PRO/1000 MT Desktop Adapter (82541)
       o   Intel PRO/1000 MT Dual Port Server Adapter (82546)
       o   Intel PRO/1000 MT Quad Port Server Adapter (82546EB)
       o   Intel PRO/1000 MT Server Adapter (82545)
       o   Intel PRO/1000 PF Dual Port Server Adapter (82571)
       o   Intel PRO/1000 PF Quad Port Server Adapter (82571)
       o   Intel PRO/1000 PF Server Adapter (82572)
       o   Intel PRO/1000 PT Desktop Adapter (82572)
       o   Intel PRO/1000 PT Dual Port Server Adapter (82571)
       o   Intel PRO/1000 PT Quad Port Server Adapter (82571)
       o   Intel PRO/1000 PT Server Adapter (82572)
       o   Intel PRO/1000 T Desktop Adapter (82544)
       o   Intel PRO/1000 T Server Adapter (82543)
       o   Intel PRO/1000 XF Server Adapter (82544)
       o   Intel PRO/1000 XT Server Adapter (82544)

LOADER TUNABLES
       Tunables	can be set at the loader(8) prompt before booting  the	kernel
       or stored in loader.conf(5).  See iflib(4) for per-instance variables.

       hw.em.disable_crc_stripping
	       Disable	or  enable  hardware  stripping	of CRC field.  This is
	       mostly useful on	BMC/IPMI shared	interfaces where stripping the
	       CRC causes remote access	over IPMI to  fail.   Default  0  (en-
	       abled).

       hw.em.eee_setting
	       Disable	or  enable Energy Efficient Ethernet.  Default 1 (dis-
	       abled).

       hw.em.smart_pwr_down
	       Enable or disable smart power down features on newer  adapters.
	       Default 0 (disabled).

       hw.em.sbp
	       Show bad	packets	when in	promiscuous mode.  Default 0 (off).

       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 max-
	       imum 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 max-
	       imum delay in which a transmit interrupt	is generated.

       hw.em.max_interrupt_rate
	       Maximum interrupts per second.  The default value is 8000.

       hw.em.rx_process_limit
	       Maximum	number	of  received  packets to process at a time, -1
	       means unlimited.	 The default value is 100.

FILES
       /dev/led/em*  identification LED	device nodes

EXAMPLES
       Make the	identification LED of em0 blink:

	     echo f2 > /dev/led/em0

       Turn the	identification LED of em0 off again:

	     echo 0 > /dev/led/em0

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 initializa-
       tion 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 (ca-
       ble).

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 sup-
       ported kernel with a supported adapter, email the specific  information
       related to the issue to <freebsd@intel.com>.

SEE ALSO
       altq(4),	   arp(4),   iflib(4),	 led(4),   netintro(4),	  ng_ether(4),
       polling(4), vlan(4), ifconfig(8)

HISTORY
       The em device driver first appeared in FreeBSD 4.4.  em was merged with
       the lem and igb device driver and converted to the iflib	 framework  in
       FreeBSD 12.0.

AUTHORS
       The   em	  driver   was	 originally   written	by  Intel  Corporation
       <freebsd@intel.com>.  It	was merged with	igb driver  and	 converted  to
       the  iflib framework by Matthew Macy <mmacy@mattmacy.io>	and Sean Bruno
       <sbruno@FreeBSD.org>.

FreeBSD	13.2			August 3, 2023				 EM(4)

NAME | SYNOPSIS | DESCRIPTION | HARDWARE | LOADER TUNABLES | FILES | EXAMPLES | DIAGNOSTICS | SUPPORT | SEE ALSO | HISTORY | AUTHORS

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