GEM(4)							   BSD Kernel Interfaces Manual 						    GEM(4)

NAME

     gem -- ERI/GEM/GMAC Ethernet device driver

SYNOPSIS

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

	   device miibus
	   device gem

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

	   if_gem_load="YES"

DESCRIPTION

     The gem driver provides support for the GMAC Ethernet hardware found mostly in the last Apple PowerBooks G3s and most G4-based Apple hard-
     ware, as well as Sun UltraSPARC machines.

     All controllers supported by the gem driver have TCP checksum offload capability for both receive and transmit, support for the reception and
     transmission of extended frames for vlan(4) and a 512-bit multicast hash filter.

HARDWARE

     Chips supported by the gem driver include:

     o	 Apple GMAC
     o	 Sun ERI 10/100 Mbps Ethernet
     o	 Sun GEM Gigabit Ethernet

     The following add-on cards are known to work with the gem driver at this time:

     o	 Sun Gigabit Ethernet PCI 2.0/3.0 (GBE/P) (part no. 501-4373)
     o	 Sun Gigabit Ethernet SBus 2.0/3.0 (GBE/S) (part no. 501-4375)

NOTES

     On sparc64 the gem driver respects the local-mac-address? system configuration variable which can be set in the Open Firmware boot monitor
     using the setenv command or by eeprom(8).	If set to ``false'' (the default), the gem driver will use the system's default MAC address for
     all of its devices.  If set to ``true'', the unique MAC address of each interface is used if present rather than the system's default MAC
     address.

     Supported interfaces having their own MAC address include the on-board Sun ERI 10/100 Mbps on boards equipped with more than one Ethernet
     interface and the Sun Gigabit Ethernet 2.0/3.0 GBE add-on cards.

SEE ALSO

     altq(4), miibus(4), netintro(4), vlan(4), eeprom(8), ifconfig(8)

HISTORY

     The gem device driver appeared in NetBSD 1.6.  The first FreeBSD version to include it was FreeBSD 5.0.

AUTHORS

     The gem driver was written for NetBSD by Eduardo Horvath <eeh@NetBSD.org>.  It was ported to FreeBSD by Thomas Moestl <tmm@FreeBSD.org> and
     later on improved by Marius Strobl <marius@FreeBSD.org>.  The man page was written by Thomas Klausner <wiz@NetBSD.org>.

BSD
								 December 25, 2009							       BSD