Datasheet

“main” (Installation and Administration) — 2004/6/25 — 13:29 — page 331 — #357

Linux on Mobile Devices

Starting with kernel 2.4, a set of alternative modules is contained in the ker-

nel sources forming the kernel PCMCIA system. The basic modules were

written by Linus Torvalds. Their support of more recent CardBus bridges is

better than that of external PCMCIA.

Unfortunately, the two systems are not compatible. They contain different

sets of card drivers. Depending on the hardware involved, only one of the

systems may be suitable. The default in SUSE LINUX is the more recent

kernel PCMCIA. To change the system, give the variable PCMCIA_SYSTEM

in the ﬁle /etc/sysconfig/pcmcia/ either the value external or

kernel. Then restart PCMCIA with rcpcmcia restart. To switch only

temporarily between systems, use rcpcmcia restart external or

rcpcmcia restart kernel. If PCMCIA is not running, use the option

start instead of restart to switch the PCMCIA system temporarily. Re-

fer to /usr/share/doc/packages/pcmcia/README.SuSE for detailed

information.

The Base Modules

The kernel modules for both systems are located in the kernel packages. In

addition, the packages pcmcia and hotplug are required. When PCM-

CIA is started, the modules pcmcia_core, i82365 (external PCMCIA) or

yenta_socket (kernel PCMCIA), and ds are loaded. In some very rare

cases, the module tcic is required instead of i82365 or yenta_socket.

They initialize the existing PCMCIA controller and provide basic function-

ality.

The Card Manager

As it is possible to change PCMCIA cards while the system is running, a

deamon monitors any activity in the PCMCIA slots. Depending on the

chosen PCMCIA system and hardware, this task is performed by the card

manager or the hotplug system of the kernel. With external PCMCIA, only

the card manager is used. For kernel PCMCIA, the card manager only han-

dles PC Card cards. CardBus cards are handled by hotplug. The card man-

ager is started by the PCMCIA start script after the base modules have been

loaded. Because hotplug manages subsystems other than PCMCIA, it has

its own start script.

331SUSE LINUX Enterprise Server