.\" Copyright (c) 2008 Stanislav Sedov <stas@FreeBSD.org>
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
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.\" $FreeBSD$
.\"
.Dd May 17, 2019
.Dt AE 4
.Os
.Sh NAME
.Nm ae
.Nd "Attansic/Atheros L2 FastEthernet controller driver"
.Sh SYNOPSIS
To compile this driver into the kernel, place the following lines in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device miibus"
.Cd "device ae"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
if_ae_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
device driver provides support for Attansic/Atheros L2 PCIe FastEthernet
controllers.
.Pp
The controller supports hardware Ethernet checksum processing, hardware
VLAN tag stripping/insertion and an interrupt moderation mechanism.
Attansic L2 also features a 64-bit multicast hash filter.
.Pp
The
.Nm
driver supports the following media types:
.Bl -tag -width ".Cm 10baseT/UTP"
.It Cm autoselect
Enable autoselection of the media type and options.
The user can manually override the autoselected mode by
adding media options to
.Xr rc.conf 5 .
.It Cm 10baseT/UTP
Select 10Mbps operation.
.It Cm 100baseTX
Set 100Mbps (FastEthernet) operation.
.El
.Pp
The
.Nm
driver provides support for the following media options:
.Bl -tag -width ".Cm full-duplex"
.It Cm full-duplex
Force full duplex operation.
.It Cm half-duplex
Force half duplex operation.
.El
.Pp
For more information on configuring this device, see
.Xr ifconfig 8 .
.Sh HARDWARE
The
.Nm
driver supports Attansic/Atheros L2 PCIe FastEthernet controllers, and
is known to support the following hardware:
.Pp
.Bl -bullet -compact
.It
ASUS EeePC 701
.It
ASUS EeePC 900
.El
.Pp
Other hardware may or may not work with this driver.
.Sh LOADER TUNABLES
Tunables can be set at the
.Xr loader 8
prompt before booting the kernel or stored in
.Xr loader.conf 5 .
.Bl -tag -width "xxxxxx"
.It Va hw.ae.msi_disable
This tunable disables MSI support on the Ethernet hardware.
The default value is 0.
.El
.Sh SYSCTL VARIABLES
The
.Nm
driver collects a number of useful MAC counter during the work.
The statistics is available via the
.Va dev.ae.%d.stats
.Xr sysctl 8
tree, where %d corresponds to the controller number.
.Sh DIAGNOSTICS
.Bl -diag
.It "ae%d: watchdog timeout."
The device has stopped responding to the network, or there is a problem with
the network connection (cable).
.It "ae%d: reset timeout."
The card reset operation has been timed out.
.It "ae%d: Generating random ethernet address."
No valid Ethernet address was found in the controller NVRAM and registers.
Random locally administered address with ASUS OUI identifier will be used
instead.
.El
.Sh SEE ALSO
.Xr altq 4 ,
.Xr arp 4 ,
.Xr miibus 4 ,
.Xr netintro 4 ,
.Xr ng_ether 4 ,
.Xr vlan 4 ,
.Xr ifconfig 8
.Sh HISTORY
The
.Nm
driver and this manual page was written by
.An Stanislav Sedov Aq Mt stas@FreeBSD.org .
It first appeared in
.Fx 7.1 .
.Sh BUGS
The Attansic L2 FastEthernet controller supports DMA but does not use a
descriptor based transfer mechanism via scatter-gather DMA.
Thus the data should be copied to/from the controller memory on each
transmit/receive.
Furthermore, a lot of data alignment restrictions apply.
This may introduce a high CPU load on systems with heavy network activity.
Luckily enough this should not be a problem on modern hardware as L2 does
not support speeds faster than 100Mbps.