ALC(4)

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.