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System Management Concepts:
Operating System and Devices

PCI Hot Plug Management

You can insert a new PCI hot plug adapter into an available PCI slot while the operating system is running. This can be another adapter of the same type that is currently installed or of a different type of PCI adapter. New resources are made available to the operating system and applications without having to restart the operating system. Some reasons for adding a hot plug adapter might include:

Note
If you add an adapter using a PCI hot plug replace or add operation, it and its child devices may not be available for specification as a boot device using the bootlist command. You may have to restart the machine to make all potential boot devices known to the operating system.

You can also remove a defective or failing PCI hot plug adapter or exchange it with another of the same type without shutting down or powering off the system. When you exchange the adapter, the existing device driver supports the adapter because it is of the same type. Device configuration and configuration information about devices below the adapter are retained for the replacement device. Some reasons for replacing an adapter might include:

When you remove a hot plug adapter, the resources provided by the adapter become unavailable to the operating system and applications. Some reasons for removing an adapter might include:

Before you can remove or replace a hot plug device, it must be unconfigured. The associated device driver must free any system resources that it has allocated for the device. This includes unpinning and freeing memory, undefining interrupt and EPOW handlers, releasing DMA and timer resources, and any other required steps. The driver must also ensure that interrupts, bus memory, and bus I/O are disabled on the device.

The system administrator must perform the following tasks before and after removing an adapter:

The remove and replace operations fail unless the device connected to the identified slot has been unconfigured and is in the defined state. You can do this with the rmdev command. Before placing the adapter in the defined state, close all applications that are using the adapter, otherwise, the command will be unsuccessful.

In some cases, the you can also perform the following tasks:

Attention: Although PCI hot plug management provides the capability of adding, removing, and replacing PCI adapters without powering off the system or restarting the operating system, not all devices in hot plug slots can be managed in this fashion. For example, the hard disk that makes up the rootvg volume group or the I/O controller to which it is attached cannot be removed or replaced without powering off the system because it is necessary for running the operating system. Before you attempt to remove or insert PCI hot plug adapters, refer to the PCI Adapter Placement Reference, (shipped with system units that support hot plug), to determine whether your adapter can be hot-swapped. Refer to your system unit documentation for instructions for installing or removing adapters.

For instructions on how to manage a PCI hot plug adapter, see the following articles in the AIX 5L Version 5.2 System Management Guide: Operating System and Devices:

Unconfiguring PCI Communications Adapters

This section provides an overview of the process for unconfiguring PCI communications adapters. This includes Ethernet, Token-ring, FDDI, and ATM adapters. For procedural information, see Unconfiguring Communications Adapters in the AIX 5L Version 5.2 System Management Guide: Operating System and Devices.

If your application is using TCP/IP protocol, you must remove the TCP/IP interface for the adapter from the network interface list before you can place the adapter in the defined state. Use the netstat command to determine whether your adapter is configured for TCP/IP and to check the active network interfaces on your adapter.

An Ethernet adapter can have two interfaces: Standard Ethernet (enX) or IEEE 802.3 (etX). X is the same number in the entX adapter name. Only one of these interfaces can be using TCP/IP at a time. For example, Ethernet adapter ent0 can have en0 and et0 interfaces.

A Token ring adapter can have only one interface: Token-ring (trX). X is the same number in the tokX adapter name. For example, Token-ring adapter tok0 has a tr0 interface.

An ATM adapter can have only one atm interface: ATM (atX). X is the same number in the atmX adapter name. For example, ATM adapter atm0 has an at0 interface. However, ATM adapters can have multiple emulated clients running over a single adapter.

The ifconfig command removes an interface from the network. The rmdev command unconfigures the PCI device while retaining its device definition in the Customized Devices Object Class. Once the adapter is in the defined state, you can use the drslot command to remove the adapter.

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