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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 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
     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 con-
     trollers:

     +o	 JMicron JMC250	PCI Express Gigabit Ethernet controller
     +o	 JMicron JMC251	PCI Express Gigabit Ethernet with Card Read Host con-
	 troller
     +o	 JMicron JMC260	PCI Express Fast Ethernet controller
     +o	 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
	     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 fea-
     ture,  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	revi-
     sion number to get	full mask revision of the controller.

FreeBSD	10.1			 June 29, 2011			  FreeBSD 10.1

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

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