Skip site navigation (1)Skip section navigation (2)

FreeBSD Man Pages

Man Page or Keyword Search:
Man Architecture
Apropos Keyword Search (all sections) Output format
home | help
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
	     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 addi-
	     tional 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 pro-
	     cessed 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 recom-
     mended 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 Eth-
     ernet 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 con-
     troller 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.

FreeBSD	9.3			 March 4, 2012			   FreeBSD 9.3

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

Want to link to this manual page? Use this URL:
<http://www.freebsd.org/cgi/man.cgi?query=jme&sektion=4&manpath=FreeBSD+9.3-RELEASE>

home | help