em(4)
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.conf(5):
if_em_load="YES"
DESCRIPTION
- The em 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 and 82573 Ethernet - controller
chips. The driver supports Transmit/Receive checksum of - fload and Jumbo
Frames only on 82540, 82543, 82544 and 82546-based adapters. - For further
hardware information, see the README included with the driv - er.
- For questions related to hardware requirements, refer to the
- documentation supplied with your Intel PRO/1000 adapter. All hard
- ware 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. - This driver version supports VLANs. For information on en
- abling VLANs,
see the README. The em driver supports the following media - types:
- autoselect Enables auto-negotiation for speed and du
- plex.
- 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 ifcon
- fig(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 and 82573 controller chips: - +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 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). - hw.em.rxd
- Number of receive descriptors allocated by the driv
- er. 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 inter
- rupts 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 lim
- its the maximum delay in which a receive interrupt is generated.
- hw.em.tx_int_delay
- This value delays the generation of transmit inter
- rupts 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 lim
- its the maximum delay in which a transmit interrupt is generat
- ed.
DIAGNOSTICS
- em%d: Unable to allocate bus resource: memory A fatal ini
- tialization
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 connec - tion (cable).
SUPPORT
- For additional information regarding building and installa
- tion, 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 informa - tion related
to the issue to <freebsdnic@mailbox.intel.com>.
SEE ALSO
HISTORY
The em device driver first appeared in FreeBSD 4.4.
AUTHORS
The em driver was written by Intel Corporation
<freebsdnic@mailbox.intel.com>.
BUGS
- Hardware-assisted VLAN processing is disabled by default.
- You can enable
it on an em interface using ifconfig(8). - BSD November 27, 2005