The current Linux network code supports a large variety of Ethernet
cards. Most drivers were written by Donald Becker, who authored a
family of drivers for cards based on the National Semiconductor 8390
chip; these have become known as the Becker Series Drivers. Many other
developers have contributed drivers, and today there are few common
Ethernet cards that aren't supported by Linux. The list of supported
Ethernet cards is growing all the time, so if your card isn't
supported yet, chances are it will be soon.
Sometime earlier in Linux's history we would have attempted to list
all supported Ethernet cards, but that would now take too much time
and space. Fortunately, Paul Gortmaker maintains the Ethernet HOWTO,
which lists each of the supported cards and provides useful
information about getting each of them running under Linux.[1] It is posted monthly to the comp.os.linux.answers newsgroup, and is
also available on any of the Linux Documentation Project mirror sites.
Even if you are confident you know how to install a particular type of
Ethernet card in your machine, it is often worthwhile taking a look at
what the Ethernet HOWTO has to say about it. You will find information
that extends beyond simple configuration issues. For example, it could
save you a lot of headaches to know the
behavior of some DMA-based Ethernet cards that use the same DMA
channel as the Adaptec 1542 SCSI controller by default. Unless you move
one of them to a different DMA channel, you will wind up with the
Ethernet card writing packet data to arbitrary locations on your hard
disk.
To use any of the supported Ethernet cards with Linux, you may use a
precompiled kernel from one of the major Linux distributions. These generally
have modules available for all of the supported drivers, and the installation
process usually allows you to select which drivers you want loaded. In the
long term, however, it's better to build your own kernel and compile only
those drivers you actually need; this saves disk space and memory.
Many of the Linux Ethernet drivers are smart enough to know how to
search for the location of your Ethernet card. This saves you having
to tell the kernel where it is manually. The Ethernet HOWTO lists
whether a particular driver uses autoprobing and in which order it
searches the I/O address for the card.
There are three limitations to the autoprobing code. First, it may not
recognize all cards properly. This is especially true for some of the cheaper
clones of common cards. Second, the kernel won't
autoprobe for more than one card unless specifically instructed. This was
a conscious design decision, as it is assumed you will want to have control
over which card is assigned to which interface. The best way to do this
reliably is to manually configure the Ethernet cards in your machine. Third,
the driver may not probe at the address that your card is configured for.
Generally speaking, the drivers will autoprobe at the addresses that the
particular device is capable of being configured for, but sometimes certain
addresses are ignored to avoid hardware conflicts with other types of cards
that commonly use that same address.
PCI network cards should be reliably detected. But if you are using more
than one card, or if the autoprobe should fail to detect your card, you
have a way to explicitly tell the kernel about the card's base address and
name.
At boot time you can supply arguments and information to the kernel that any
of the kernel components may read. This mechanism allows you
to pass information to the kernel that Ethernet drivers can use to locate your
Ethernet hardware without making the driver probe.
If you use lilo to boot your system, you can pass parameters
to the kernel by specifying them through the
append option in the
lilo.conf file. To inform the kernel about an
Ethernet device, you can pass the following parameters:
ether=irq,base_addr,[param1,][param2,]name |
The first four parameters are numeric, while the last is the device
name. The irq,
base_addr, and
name parameters are required, but the two
param parameters are optional. Any of the
numeric values may be set to zero, which causes the kernel to
determine the value by probing.
The first parameter sets the IRQ assigned to the device. By default, the
kernel will try to autodetect the device's IRQ channel. The 3c503 driver,
for example, has a special feature that selects a free IRQ from the list
5, 9, 3, 4 and configures the card to use this line.
The base_addr parameter gives the I/O base address
of the card; a value of zero tells the kernel to probe the addresses listed
above.
Different drivers use the next two parameters differently. For shared-memory cards, such as the WD80x3, they specify starting and ending
addresses of the shared memory area. Other cards commonly use
param1 to set the level at which debugging
information is displayed. Values of 1 through 7 denote increasing levels of
verbosity, while 8 turns them off altogether; 0 denotes the default.
The 3c503 driver uses param2 to choose between the
internal transceiver (default) or an external transceiver (a value of 1).
The former uses the card's BNC connector; the latter uses its AUI port.
The param arguments need not be included at all
if you don't have anything special to configure.
The first non-numeric argument is interpreted by the kernel as the
device name. You must specify a device name for each Ethernet card you
describe.
If you have two Ethernet cards, you can have Linux autodetect one card
and pass the second card's parameters with lilo,
but you'll probably want to manually configure both cards. If you
decide to have the kernel probe for one and manually configure the
second, you must make sure the kernel doesn't accidentally find the
second card first, or else the other one won't be registered at
all. You do this by passing lilo a reserve option, which explicitly tells the
kernel to avoid probing the I/O space taken up by the second card. For
instance, to make Linux install a second Ethernet card at
0x300 as eth1, you would pass
the following parameters to the kernel:
reserve=0x300,32 ether=0,0x300,eth1 |
The reserve option makes sure no driver
accesses the second card's I/O space when probing for some device. You may
also use the kernel parameters to override autoprobing for
eth0 :
reserve=0x340,32 ether=0,0x340,eth0 |
You can turn off autoprobing altogether. You might do this, for example, to
stop a kernel probing for an Ethernet card you might have temporarily removed.
Disabling autoprobing is as simple as specifying a
base_addr argument of –1:
To supply these parameters to the kernel at boot time, you enter the
parameters at the lilo "boot:" prompt. To have lilo
give you the "boot:" at the prompt, you must press
any one of the Control, Alt or Shift keys while
lilo is booting. If you press the Tab key at the
prompt, you will be presented with a list of kernels that you may
boot. To boot a kernel with parameters supplied, enter the name of the
kernel you wish to boot, followed by a space, then followed by the
parameters you wish to supply. When you press the Enter key,
lilo will load that kernel and boot it with the
parameters you've supplied.
To make this change occur automatically on each reboot, enter the parameters
into the /etc/lilo.conf using the
append= keyword. An example might look like this:
boot=/dev/hda
root=/dev/hda2
install=/boot/boot.b
map=/boot/map
vga=normal
delay=20
append="ether=10,300,eth0"
image=/boot/vmlinuz-2.2.14
label=2.2.14
read-only |
After you've edited lilo.conf, you must rerun
the lilo command to activate the change.
