NAME
gem —
ERI/GEM/GMAC Ethernet device
driver
SYNOPSIS
gem* at pci? dev ? function ?
gem* at sbus? slot ? offset ?
Configuration of PHYs may also be necessary. See
mii(4).
DESCRIPTION
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.
SEE ALSO
bmtphy(4),
ifmedia(4),
intro(4),
mii(4),
ifconfig(8)
Sun Microsystems,
GEM Gigabit Ethernet ASIC Specification,
http://www.sun.com/processors/manuals/ge.pdf.
Sun Microsystems,
Sbus GEM Specification,
http://mediacast.sun.com/users/Barton808/media/gem_sbus-1.pdf.
HISTORY
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.
AUTHORS
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⟩.
BUGS
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
half-duplex mode.