Browse Prior Art Database

Power Management System Incorporating Device Handshaking to Monitor User Activity

IP.com Disclosure Number: IPCOM000118960D
Original Publication Date: 1997-Sep-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 3 page(s) / 135K

Publishing Venue

IBM

Related People

Craig, JA: AUTHOR

Abstract

Disclosed is a power management software system that provides for the optimal monitoring of user-input device activity in a computer system. Status polling, power event, and power state mechanisms are combined to provide a superior solution for integrating user-input peripherals into the power management system.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 46% of the total text.

Power Management System Incorporating Device Handshaking to Monitor
User Activity

      Disclosed is a power management software system that provides
for the optimal monitoring of user-input device activity in a
computer system.  Status polling, power event, and power state
mechanisms are combined to provide a superior solution for
integrating user-input peripherals into the power management system.

      A key function of computer power management systems is to
monitor user-input peripheral devices for instances of activity and
periods of idleness so that power-saving system states are entered
and exited in a manner that minimizes average energy dissipation
while maximizing software performance.  There are three aspects to
monitoring user-input devices:
  1.  Monitoring a set of devices for idleness.  Power management
       uses this kind of monitoring when the system is operating
       in the highest system power state, and so it is looking for
       an opportunity to conserve energy (by moving to a more
       energy-saving state).
  2.  Monitoring a set of devices for both activity and idleness.
       This type of monitoring occurs when the system operates in
       any middle system power state.  User activity leads power
       management to implement transitions to higher, or less
       conserving power states, while periods of idleness lead
       to transitions to lower, or more conserving, power states.
  3.  Monitoring a set of devices for activity.  This type of
       monitoring occurs in the lowest, most energy conserving
       state.  The first instance of user activity leads power
       management software to implement a transition to an active
       system power state.

      The problem of monitoring user-input devices for the purpose of
power management has traditionally been solved by implementing one of
two methods:
  1.  A central power management facility that periodically polls
       user-input device status.  Polls for idleness have a low
       frequency, while polls or activity have a high frequency.
  2.  Participatory user-input device drivers that generate and
       communicate power events based on the activity and idleness
       of their device.

      Neither method alone provides an optimal solution for all three
aspects of device monitoring.  The polling method is non-optimal for
activity monitoring since there is a latency between polls, and a
high-frequency poll reduces software performance.  The event method
is non-optimal for idleness monitoring, since the generation of a
power event for every instance of device activity can seriously
degrade software performance.

      The system described herein combines the poll and event methods
and adds a power-state control method, or handshake, in order to
provide an optimal solution for each aspect of user-inp...