Specifications

default is to use the BIOS.

4.3 The `pci=conf1' and `pci=conf2' Arguments

If PCI direct mode is enabled, the use of these enables either configuration Type 1 or Type 2. These implicitly

clear the PCI BIOS probe flag (i.e. `pci=nobios') too.

4.4 The `pci=irqmask=' Argument

This allows the user to supply an IRQ mask value, which is converted using strtol(). It will set a bit mask of

IRQs allowed to be assigned automatically to PCI devices. You can make the kernel exclude IRQs of your

ISA cards this way.

4.5 The `pci=lastbus=' Argument

This allows the user to supply a lastbus value, which is converted using strtol(). It will scan all buses till bus

N. Can be useful if the kernel is unable to find your secondary buses and you want to tell it explicitly which

ones they are.

4.6 The `pci=noacpi' Argument

This disables the use of ACPI routing information during the PCI configuration stages.

4.7 The `pci=nopeer' Argument

This disables the default peer bridge fixup, which according to the source does the following:

``In case there are peer host bridges, scan bus behind each of them. Although several sources claim that the

host bridges should have header type 1 and be assigned a bus number as for PCI2PCI bridges, the reality

doesn't pass this test and the bus number is usually set by BIOS to the first free value.''

4.8 The `pci=nosort' Argument

Using this argument instructs the kernel to not sort the PCI devices during the probing phase.

4.9 The `pci=off' Argument

Using this option disables all PCI bus probing. Any device drivers that make use of PCI functions to find and

initialize hardware will most likely fail to work.

4.10 The `pci=usepirqmask' Argument

This sets the USE_PIRQ_MASK flag during PCI init. The kernel will honour the possible IRQ mask stored in

the BIOS PIR table. This is needed on some systems with broken BIOSes, notably some HP Pavilion N5400

and Omnibook XE3 notebooks. This will have no effect if ACPI IRQ routing is enabled.

The Linux BootPrompt−HowTo

4.3 The `pci=conf1' and `pci=conf2' Arguments 19