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JME(4)                 FreeBSD Kernel Interfaces Manual                 JME(4)

NAME
     jme - JMicron Gigabit/Fast Ethernet driver

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

           device miibus
           device jme

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

           if_jme_load="YES"

DESCRIPTION
     The jme device driver provides support for JMicron JMC25x PCI Express
     Gigabit Ethernet controllers and JMicron JMC26x PCI Express Fast Ethernet
     controllers.

     All LOMs supported by the jme driver have TCP/UDP/IP checksum offload for
     both transmit and receive, TCP segmentation offload (TSO), hardware VLAN
     tag stripping/insertion features, Wake On Lan (WOL) and an interrupt
     coalescing/moderation mechanism as well as a 64-bit multicast hash
     filter.

     The JMC25x also supports Jumbo Frames (up to 9216 bytes), which can be
     configured 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 jme driver supports the following media types:

     autoselect       Enable autoselection of the media type and options.  The
                      user can manually override the autoselected mode by
                      adding media options to rc.conf(5).

     10baseT/UTP      Set 10Mbps operation.

     100baseTX        Set 100Mbps (Fast Ethernet) operation.

     1000baseTX       Set 1000baseTX operation over twisted pair.

     The jme driver supports the following media options:

     full-duplex      Force full duplex operation.

     half-duplex      Force half duplex operation.

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

HARDWARE
     The jme device driver provides support for the following Ethernet
     controllers:

     +o   JMicron JMC250 PCI Express Gigabit Ethernet controller
     +o   JMicron JMC251 PCI Express Gigabit Ethernet with Card Read Host
         controller
     +o   JMicron JMC260 PCI Express Fast Ethernet controller
     +o   JMicron JMC261 PCI Express Gigabit Ethernet with Card Read Host
         controller

LOADER TUNABLES
     Tunables can be set at the loader(8) prompt before booting the kernel or
     stored in loader.conf(5).

     hw.jme.msi_disable
             This tunable disables MSI support on the Ethernet hardware.  The
             default value is 0.

     hw.jme.msix_disable
             This tunable disables MSI-X support on the Ethernet hardware.
             The default value is 0.

SYSCTL VARIABLES
     The following variables are available as both sysctl(8) variables and
     loader(8) tunables:

     dev.jme.%d.tx_coal_to
             Maximum amount of time to delay for Tx completion interrupt in
             units of 1us.  The accepted range is 1 to 65535, the default is
             100 (100us).

     dev.jme.%d.tx_coal_pkt
             Maximum number of packets to fire Tx completion interrupt.  The
             accepted range is 1 to 255, the default is 8.

     dev.jme.%d.rx_coal_to
             Maximum amount of time to delay for Rx completion interrupt in
             units of 1us.  The accepted range is 1 to 65535, the default is
             100 (100us).

     dev.jme.%d.rx_coal_pkt
             Maximum number of packets to fire Rx completion interrupt.  The
             accepted range is 1 to 255, the default is 2.

     dev.jme.%d.process_limit
             Maximum amount of Rx events to be processed in the event loop
             before rescheduling a taskqueue.  The accepted range is 10 to
             255, the default value is 128 events.  The interface does not
             need to be brought down and up again before a change takes
             effect.

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

HISTORY
     The jme driver was written by Pyun YongHyeon <yongari@FreeBSD.org>.  It
     first appeared in FreeBSD 7.1.

CAVEATS
     The jme driver tries to avoid unnecessary station address reprogramming
     for controllers that use eFuse to store station address.  The number of
     times that eFuse can be safely reprogrammed is 16 at most.  In addition,
     there is no way to restore factory default station address once station
     address is reprogrammed via eFuse.  It is highly recommended not to
     reprogram station address and it is responsibility of administrator to
     store original station address into a safe place when station address
     should be changed.

     There are two known 1000baseT link establishment issues with JMC25x.  If
     the full mask revision number of JMC25x controller is less than or equal
     to 4 and link partner enabled IEEE 802.3az Energy Efficient Ethernet
     feature,  the controller would not be able to establish a 1000baseT link.
     Also if the length of cable is longer than 120 meters, controller can not
     establish a 1000baseT link.  The known workaround for the issue is to
     force manual link configuration with 100baseTX instead of relying on
     auto-negotiation.  The full mask revision number of controller could be
     checked with verbose kernel boot option.  Use lower nibble of chip
     revision number to get full mask revision of the controller.

FreeBSD 11.0-PRERELEASE          June 29, 2011         FreeBSD 11.0-PRERELEASE

NAME | SYNOPSIS | DESCRIPTION | HARDWARE | LOADER TUNABLES | SYSCTL VARIABLES | SEE ALSO | HISTORY | CAVEATS

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