NAME

     alc — Atheros AR813x/AR815x Gigabit/Fast Ethernet driver

SYNOPSIS

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

           device miibus
           device alc

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

           if_alc_load="YES"

DESCRIPTION

     The alc device driver provides support for Atheros AR813x and AR815x PCI Express
     Gigabit/Fast Ethernet controllers.

     All LOMs supported by the alc driver have TCP/UDP/IP checksum offload for transmit, TCP
     segmentation offload (TSO), hardware VLAN tag stripping/insertion features, Wake On Lan
     (WOL) and an interrupt moderation mechanism as well as a 64-bit multicast hash filter.

     The AR813x and AR815x supports Jumbo Frames (up to 9216 and 6144 bytes, respectively), 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 alc 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 alc 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 alc device driver provides support for the following Ethernet controllers:

     •   Atheros AR8131 PCI Express Gigabit Ethernet controller
     •   Atheros AR8132 PCI Express Fast Ethernet controller
     •   Atheros AR8151 v1.0 PCI Express Gigabit Ethernet controller
     •   Atheros AR8151 v2.0 PCI Express Gigabit Ethernet controller
     •   Atheros AR8152 v1.1 PCI Express Fast Ethernet controller
     •   Atheros AR8152 v2.0 PCI Express Fast Ethernet controller

LOADER TUNABLES

     Tunables can be set at the loader(8) prompt before booting the kernel or stored in
     loader.conf(5).

     hw.alc.msi_disable
             This tunable disables MSI support on the Ethernet hardware.  The default value is 0.

     hw.alc.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.alc.%d.int_rx_mod
             Maximum amount of time to delay receive interrupt processing in units of 1us.  The
             accepted range is 0 to 130000, the default is 100(100us).  Value 0 completely
             disables the interrupt moderation.

     dev.alc.%d.int_tx_mod
             Maximum amount of time to delay transmit interrupt processing in units of 1us.  The
             accepted range is 0 to 130000, the default is 1000(1ms).  Value 0 completely
             disables the interrupt moderation.

     dev.alc.%d.process_limit
             Maximum amount of Rx frames to be processed in the event loop before rescheduling a
             taskqueue.  The accepted range is 32 to 255, the default value is 64 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 alc driver was written by Pyun YongHyeon ⟨yongari@FreeBSD.org⟩.  It first appeared in
     FreeBSD 8.0.