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GEM(4) NetBSD Kernel Interfaces Manual GEM(4)
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gem -- ERI/GEM/GMAC Ethernet device driver
gem* at pci? dev ? function ?
gem* at sbus? slot ? offset ?
Configuration of PHYs may also be necessary. See mii(4).
The gem driver provides support for the GMac Ethernet hardware found
mostly in the last Apple PowerBooks G3s and most G4-based Apple hardware,
as well as many Sun UltraSPARCs.
Cards supported by this driver include:
· Sun GEM Gigabit Ethernet (SX fibre variants)
· Sun ERI 10/100
· Apple GMAC
The GEM family supports hardware checksumming to assist in computing IPv4
TCP checksums. The gem driver supports this feature of the chip. See
ifconfig(8) for information on how to enable this feature.
bmtphy(4), ifmedia(4), intro(4), makphy(4), mii(4), ifconfig(8)
Sun Microsystems, GEM Gigabit Ethernet ASIC Specification,
Sun Microsystems, Sbus GEM Specification,
The gem device driver appeared in NetBSD 1.6. Support for PCI SX fibre
cards was added in NetBSD 5.0. Support for SBus SX fibre cards was added
in NetBSD 5.0.
The gem driver was written by Eduardo Horvath <eeh@NetBSD.org>. SX fibre
support was added by Julian Coleman <jdc@NetBSD.org>. The man page was
written by Thomas Klausner <wiz@NetBSD.org>.
The hardware checksumming support does not support IPv4 UDP, although
this was allowed prior to NetBSD 5.0. Also, the hardware IPv4 TCP
receive checksumming support has bugs, so this is disabled.
On the SX fibre variants of the hardware, the link will stay down if
there is a duplex mismatch. Also, packet transmission may fail when in
NetBSD 9.1 June 2, 2018 NetBSD 9.1