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PPC(4) Device Drivers Manual PPC(4)

ppcParallel Port Chipset driver

device ppc

In /boot/device.hints:
hint.ppc.0.at="isa"
hint.ppc.0.irq="7"

For one or more PPBUS busses:
device ppbus

The ppc driver provides low level support to various parallel port chipsets for the ppbus(4) system.

During the probe phase, ppc detects parallel port chipsets and initializes private data according to their operating mode: COMPATIBLE, NIBBLE, PS/2, EPP, ECP and other mixed modes. If a mode is provided at startup through the flags variable of the boot interface, the operating mode of the chipset is forced according to flags and the hardware supported modes.

During the attach phase, ppc allocates a ppbus structure, initializes it and calls the ppbus attach function.

Some parallel port chipsets are explicitly supported: detection and initialisation code has been written according to their datasheets.

You may want to add support for the newest chipset your motherboard was sold with. For the ISA bus, just retrieve the specs of the chipset and write the corresponding () function. Then add an entry to the general purpose () function.

Your () function should ensure that if the mode field of the flags boot variable is not null, then the operating mode is forced to the given mode and no other mode is available and ppb->ppb_avm field contains the available modes of the chipset.

ppbus(4), ppi(4), device.hints(5)

The ppc manual page first appeared in FreeBSD 3.0.

This manual page was written by Nicolas Souchu.

The chipset detection process may corrupt your chipset configuration. You may disable chipset specific detection by using the above flags.

March 5, 1998 FreeBSD-12.0