Learning Debian GNU/Linux By Bill McCarty 1st Edition September 1999 1-56592-705-2, Order Number: 7052 360 pages, $34.95 , Includes CD-ROM

Appendix D Managing the Boot Process

 

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D.6 Using Loadable Ethernet Drivers

Early versions of Linux used a so-called monolithic kernel. At that time, Linux distributions typically included several kernels, offering support for a variety of devices that might be needed to boot and install a Linux system. Devices not needed to boot and install a system - so-called special devices - had second-class status. To access special devices, users had to compile customized kernels that included support for those devices. When a user added a device to a system, it was often necessary to compile a new kernel, which was something of an inconvenience.

More recent versions of Linux feature a modular kernel, which allows drivers to be dynamically loaded on command. This makes it much easier than before to configure your Linux system to support Ethernet cards and other special devices. Debian GNU/Linux is generally able to configure your primary Ethernet card automatically, by probing for it during installation of Linux.

However, the autoprobe doesn't always succeed. Moreover, if you have more than one Ethernet card, the installation program sets up only the first card it finds. To set up additional cards, you need to know a bit about Linux's loadable modules.

D.6.1 Dynamically Loading a Modular Driver

To dynamically load a modular driver, you issue the following command:

insmod 
driver

Where driver specifies the module to be loaded. Table D.9 lists modular Ethernet drivers and the cards they support. As an example, the command:

insmod ne2k-pci

loads the modular driver for the PCI-based NE2000 Ethernet card.

Table D.9: Modular Ethernet Drivers and Supported Cards

Driver	Cards
3c501	3Com 3c501
3c503	3Com EtherLink II
3c505	3Com EtherLink Plus
3c507	3Com EtnerLink 16
3c509	3Com EtherLink III
3c515	3Com EtherLink XL
8390	National Semiconductor NS8390
a2065	Commodore/Ameristar A2065
ac3200	Ansel Communications AC3200 (EISA)
apricot	Apricot 82596
arcnet	ARCnet COM9026 and COM20020
ariadne	Village Tronic Ariadne
at1700	Allied Telesis AT1700
atari_bionet	Atari BIONET-100
atari_pamsnet	Atari PAMsNet
atarilance	Atari VME Lance
cops	LocalTalk PC
de4x5	EtherWORKS DE425, DE434, DE435, DE450, DE500, DC21040, DC21041, DC21142, DC21143
de600	D-Link DE-600
de620	D-Link DE-620
depca	DEPCA/EtherWORKS DEPCA, DE100, DE101, DE200, DE201, DE202, DE210, DE422
dgrs	Digi RightSwitch SE-X
e2100	Cabletron E2100
eepro	Intel EtherExpress Pro/10
eepro100	Intel EtherExpress Pro/100
eexpress	Intel EtherExpress
epic100	SMC 83c170 EPIC/100
eth16i	ICL EtherTeam 16i, EtherTeam 32 (EISA)
ewrk3	EtherWORKS DE203, DE204, DE205
hp-plus	HP PCLAN/Plus
hp	HP LAN
hp100	HP J2585A, J2585B, J2970, J2973, J2573Compex ReadyLink ENET100-VG4Compex FreedomLine 100/VG
hydra	Hydra Amiganet
ibmtr	IBM token ring
lance	Allied Telesis AT1500HP J2405ANE 2100, 2500
ne	NE1000, NE2000 (non-PCI)
ne2k-pci	NE2000 (PCI)
ni52	Rascal-Interlan NI5210
ni65	Rascal-Interlan NI6510
pcnet	AMD PCnet32- and PCnetPCI-based cards
rt18139	Cards based on the RTL8129 and RTL8139 PCI Ethernet chips, such as: ALFA GFC2206 Allied Telesyn AT2550 Genius GF100TXR (RTL8139) NDC Communications NE100TX-E SiS 900 (PCI) SMC 1211TX (PCI)
smc-ultra	SMC Ultra, UltraEZ, Ultra32
smc9194	SMC 9000
tlan	Various Compaq and Olicom cards
tulip	Cards based on the DEC 21040/21041/21140/21142/21143, such as: Accton EtherDuo PCI, EN1207 Adaptec ANA6901/C, ANA6911/TX C-NET CNE-935 Cogent EM100, EM110, EM400, EM960, EM964 Quartet Danpex EN-9400P3 D-Link DFE500-Tx, DE-530CT, DFE-540TX Linksys EtherPCI Kingston EtherX KNT40T, EtherX KNE100TX Netgear FX310 TX 10/100 SMC EtherPower, 8432BT, EtherPower10/100, EtherPower10/100 Surecom EP-320X
tulip (cont.)	Thomas Conrad TC5048 Znyx ZX312 EtherAction, ZX314, ZX315 EtherArray, ZX342, ZX344, ZX345, ZX346, ZX348, ZX351
wavelan	AT&T/NCR GIS WaveLAN
wd	WD8003, WD8013
yellowfin	Packet Engines G-NIC

When a driver is loaded, it generally probes to locate the supported device. In case an autoprobe fails, most drivers let you specify the I/O port and IRQ by using a command like the following:

insmod ne2k=pci io=0x280 irq=11

Some cards support additional options; these are documented in the file /usr/src/linux/Documentation/networking/net-modules.txt.

D.6.2 Loading Modular Drivers at Boot Time

The Linux kernel automatically loads modules specified in the module configuration file, /etc/conf.modules. So, once you've determined the proper module and options required by your Ethernet card, you can add a line or two to the module configuration file so that your card will be made ready to operate each time you boot your system.

The alias directive associates a logical module name with an actual module. Logical module names specify types of devices; for example, eth0 specifies the first Ethernet card in a system and eth1 specifies the second Ethernet card in a system. Suppose your system includes two Ethernet cards: a non-PCI-based NE2000 and an SMC EtherPower, which is based on DEC's TULIP chip. You could use the following directives to automatically load these modules at boot time:

alias eth0 ne
alias eth1 tulip

If a driver requires options, you can specify them by using an options directive, which has the following form:

options 
driver argument=
value[,
value,...]
            
argument=
value[,
value,...] ...

For example, you might specify the I/O port and IRQ used by the NE2000 card like this:

options ne io=0x280 irq=12

Most ISA modules accept parameters like io=0x340 and irq=12 on the insmod command line. You should supply these parameters to avoid probing for the card. Unlike PCI and EISA devices, ISA devices sometimes cannot be safely auto-probed.

D.6.3 Administering Modular Drivers

The lsmod command, which takes no arguments, lists the loaded modular drivers. To unload a modular driver, specify the driver as the argument of the rmmod command. For example, to remove the ne driver, issue the command:

rmmod ne

By specifying the -a argument, you can cause rmmod to unload every unused module; that is, every module not associated with an operational device:

rmmod -a

You can't remove a module that's in use; therefore, you must shut down the device before removing it. To shut down an Ethernet device, you can use linuxconfig. Or, you can issue the following command:

ifconfig eth
n down

where eth n specifies the logical device (for example, eth0 or eth1).

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D.5 Boot Parameters		E. Linux Command Quick Reference

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