Browse Prior Art Database

Method for Orderly Computer Device Power Transitioning

IP.com Disclosure Number: IPCOM000123877D
Original Publication Date: 1999-Jun-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 2 page(s) / 70K

Publishing Venue

IBM

Related People

Kubik, J: AUTHOR [+3]

Abstract

Modern computer hardware can support multiple power levels. Transitioning between these levels needs to be handled in an orderly fashion. For instance, a hardware bus needs to be powered up before the devices connected to it. The main power supply must be up before any buses can be powered. This disclosure proposes a simple, yet effective method for implementing power transition order.

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Method for Orderly Computer Device Power Transitioning

   Modern computer hardware can support multiple power
levels.  Transitioning between these levels needs to be handled in an
orderly fashion.  For instance, a hardware bus needs to be powered up
before the devices connected to it.  The main power supply must be up
before any buses can be powered.  This disclosure proposes a simple,
yet effective method for implementing power transition order.

   While there are many existing methods of implementing
device power transition order, most are cumbersome to implement.
Perhaps the most accurate method may be to create a device power tree
such as proposed by the ACPI specification.  This technique shows
every power dependency between all devices within a computer.
However, ACPI requires system BIOS support to recognize the device
power hierarchy and is therefore machine dependent and difficult to
implement across platforms.  The dependency tree is also often
difficult to calculate and can change as devices are added or removed
from a computer.  Nor does it take into account software-only virtual
devices or applications wishing to participate in power management.
For light-weight Network Client type machines a simpler solution is
required.

   This disclosure demonstrates a simple method of
implementing orderly power transitions.  Proposed are device
classifications which classify a device by its typical position
within a power hierarchy and determine the order of po...