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JME(4)			     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 Giga-
     bit  Ethernet controllers and JMicron JMC26x PCI Express Fast Ethernet con-
     trollers.

     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  coa-
     lescing/moderation mechanism as well as a 64-bit multicast hash filter.

     The JMC25x also supports Jumbo Frames (up to 9216 bytes), which can be con-
     figured  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 con-
     trollers:

     *	 JMicron JMC250 PCI Express Gigabit Ethernet controller
     *	 JMicron JMC251 PCI Express Gigabit Ethernet with Card	Read  Host  con-
	 troller
     *	 JMicron JMC260 PCI Express Fast Ethernet controller
     *	 JMicron  JMC261  PCI  Express Gigabit Ethernet with Card Read Host con-
	 troller

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 ac-
	     cepted 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 ac-
	     cepted 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  be-
	     fore  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 9.0			  June 29, 2011 			  JME(4)
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