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:

       •   JMicron JMC250 PCI Express Gigabit Ethernet controller
       •   JMicron JMC251 PCI Express Gigabit Ethernet with Card Read Host controller
       •   JMicron JMC260 PCI Express Fast Ethernet controller
       •   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
               This  variable sets the maximum amount of time to delay before sending a Tx completion interrupt,
               in microseconds.  The accepted range is 1 to 65535; the default is 100 (100us).

       dev.jme.%d.tx_coal_pkt
               This variable sets the maximum number of outgoing packets which may be coalesced together into  a
               single Tx completion interrupt.  The accepted range is 1 to 255; the default is 8.

       dev.jme.%d.rx_coal_to
               This  variable  sets  the  maximum  amount  of time to wait for additional packets to arrive (for
               possible packet coalescing) before firing an  Rx  completion  interrupt,  in  microseconds.   The
               accepted range is 1 to 65535; the default is 100 (100us).

       dev.jme.%d.rx_coal_pkt
               This variable sets the maximum number of incoming packets which may be coalesced into a single Rx
               completion interrupt.  The accepted range is 1 to 255; the default is 2.

       dev.jme.%d.process_limit
               This  variable  sets the maximum number of events that will be processed in a single batch before
               the handler is requeued into 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 the factory default station address once the station address has
       been reprogrammed via eFuse.  It is highly recommended not to reprogram the station address and it is the
       responsibility of the administrator to store the original station address in a safe  place  when  station
       address is 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 the link partner enabled the IEEE 802.3az Energy
       Efficient Ethernet feature,  the controller will not be able to establish a 1000baseT link.  Also, if the
       length of the cable is longer than 120 meters, the controller can not establish a  1000baseT  link.   The
       known workaround for these issues is to force manual link configuration with 100baseTX instead of relying
       on  auto-negotiation.  The full mask revision number of controller can be checked with the verbose kernel
       boot option.  Use the lower nibble of the chip revision number to get  the  full  mask  revision  of  the
       controller.

Debian                                            March 4, 2012                                           JME(4)