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.\" $FreeBSD$
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.Dd October 11, 2011
.Dt EM 4
.Os
.Sh NAME
.Nm em
.Nd "Intel(R) PRO/1000 Gigabit Ethernet adapter driver"
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following line in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device em"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
if_em_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
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.
The identification LEDs of the adapters supported by the
.Nm
driver can be controlled via the
.Xr led 4
API for localization purposes.
For further hardware information, see the
.Pa README
included with the driver.
.Pp
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 .
.Pp
Support for Jumbo Frames is provided via the interface MTU setting.
Selecting an MTU larger than 1500 bytes with the
.Xr ifconfig 8
utility configures the adapter to receive and transmit Jumbo Frames.
The maximum MTU size for Jumbo Frames is 16114.
.Pp
This driver version supports VLANs.
The
.Nm
driver supports the following media types:
.Bl -tag -width ".Cm 10baseT/UTP"
.It Cm autoselect
Enables auto-negotiation for speed and duplex.
.It Cm 10baseT/UTP
Sets 10Mbps operation.
Use the
.Cm mediaopt
option to select
.Cm full-duplex
mode.
.It Cm 100baseTX
Sets 100Mbps operation.
Use the
.Cm mediaopt
option to select
.Cm full-duplex
mode.
.It Cm 1000baseSX
Sets 1000Mbps operation.
Only
.Cm full-duplex
mode is supported at this speed.
.It Cm 1000baseTX
Sets 1000Mbps operation.
Only
.Cm full-duplex
mode is supported at this speed.
.El
.Pp
The
.Nm
driver supports the following media options:
.Bl -tag -width ".Cm full-duplex"
.It Cm full-duplex
Forces full-duplex operation
.It Cm half-duplex
Forces half-duplex operation.
.El
.Pp
Only use
.Cm mediaopt
to set the driver to
.Cm full-duplex .
If
.Cm mediaopt
is not specified, the driver defaults to
.Cm half-duplex .
.Pp
For more information on configuring this device, see
.Xr ifconfig 8 .
.Sh HARDWARE
The
.Nm
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:
.Pp
.Bl -bullet -compact
.It
Intel PRO/1000 CT Network Connection (82547)
.It
Intel PRO/1000 F Server Adapter (82543)
.It
Intel PRO/1000 Gigabit Server Adapter (82542)
.It
Intel PRO/1000 GT Desktop Adapter (82541PI)
.It
Intel PRO/1000 MF Dual Port Server Adapter (82546)
.It
Intel PRO/1000 MF Server Adapter (82545)
.It
Intel PRO/1000 MF Server Adapter (LX) (82545)
.It
Intel PRO/1000 MT Desktop Adapter (82540)
.It
Intel PRO/1000 MT Desktop Adapter (82541)
.It
Intel PRO/1000 MT Dual Port Server Adapter (82546)
.It
Intel PRO/1000 MT Quad Port Server Adapter (82546EB)
.It
Intel PRO/1000 MT Server Adapter (82545)
.It
Intel PRO/1000 PF Dual Port Server Adapter (82571)
.It
Intel PRO/1000 PF Quad Port Server Adapter (82571)
.It
Intel PRO/1000 PF Server Adapter (82572)
.It
Intel PRO/1000 PT Desktop Adapter (82572)
.It
Intel PRO/1000 PT Dual Port Server Adapter (82571)
.It
Intel PRO/1000 PT Quad Port Server Adapter (82571)
.It
Intel PRO/1000 PT Server Adapter (82572)
.It
Intel PRO/1000 T Desktop Adapter (82544)
.It
Intel PRO/1000 T Server Adapter (82543)
.It
Intel PRO/1000 XF Server Adapter (82544)
.It
Intel PRO/1000 XT Server Adapter (82544)
.El
.Sh LOADER TUNABLES
Tunables can be set at the
.Xr loader 8
prompt before booting the kernel or stored in
.Xr loader.conf 5 .
.Bl -tag -width indent
.It Va hw.em.rxd
Number of receive descriptors allocated by the driver.
The default value is 1024 for adapters newer than 82547,
and 256 for older ones.
The 82542 and 82543-based adapters can handle up to 256 descriptors,
while others can have up to 4096.
.It Va hw.em.txd
Number of transmit descriptors allocated by the driver.
The default value is 1024 for adapters newer than 82547,
and 256 for older ones.
The 82542 and 82543-based adapters can handle up to 256 descriptors,
while others can have up to 4096.
.It Va 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.
.It Va hw.em.rx_abs_int_delay
If
.Va hw.em.rx_int_delay
is non-zero, this tunable limits the maximum delay in which a receive
interrupt is generated.
.It Va hw.em.tx_int_delay
This value delays the generation of transmit interrupts in units of
1.024 microseconds.
The default value is 64.
.It Va hw.em.tx_abs_int_delay
If
.Va hw.em.tx_int_delay
is non-zero, this tunable limits the maximum delay in which a transmit
interrupt is generated.
.El
.Sh FILES
.Bl -tag -width /dev/led/em*
.It Pa /dev/led/em*
identification LED device nodes
.El
.Sh EXAMPLES
Make the identification LED of em0 blink:
.Pp
.Dl "echo f2 > /dev/led/em0"
.Pp
Turn the identification LED of em0 off again:
.Pp
.Dl "echo 0 > /dev/led/em0"
.Sh DIAGNOSTICS
.Bl -diag
.It "em%d: Unable to allocate bus resource: memory"
A fatal initialization error has occurred.
.It "em%d: Unable to allocate bus resource: interrupt"
A fatal initialization error has occurred.
.It "em%d: watchdog timeout -- resetting"
The device has stopped responding to the network, or there is a problem with
the network connection (cable).
.El
.Sh SUPPORT
For general information and support,
go to the Intel support website at:
.Pa http://support.intel.com .
.Pp
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 .
.Sh SEE ALSO
.Xr altq 4 ,
.Xr arp 4 ,
.Xr igb 4 ,
.Xr led 4 ,
.Xr netintro 4 ,
.Xr ng_ether 4 ,
.Xr polling 4 ,
.Xr vlan 4 ,
.Xr ifconfig 8
.Sh HISTORY
The
.Nm
device driver first appeared in
.Fx 4.4 .
.Sh AUTHORS
The
.Nm
driver was written by
.An Intel Corporation Aq freebsdnic@mailbox.intel.com .
.Sh BUGS
Hardware-assisted VLAN processing is disabled by default.
You can enable it on an
.Nm
interface using
.Xr ifconfig 8 .