Video Power Management; Hard Drive And Bay Power Management; Msio Super I/O Power Management; Audio Power Management - Compaq Armada e500 Series Reference Manual

Video Power Management

The RAGE Mobility-P graphics controller has several internal timers that monitor
subsystems within the video controller. When one of these areas becomes inactive for a
long period of time, the controller disables that area, saving overall system power.
RAGE Mobility-P power management logic supports four device power states: On,
Standby, Suspend, and Off. Each power state can be achieved by software control bits,
hardware pins, or hardware timers. By implementing power management capability
registers in PCI configuration space, the chip becomes directly controllable from the
system BIOS. Three dedicated pins (CLKRUN#, AGP_BUSY#, and STP_AGP#) give
full controllability of the PCI and AGP bus interface to the system chipset.
Clocks to every major functional block (2D, 3D, video, LCD out, TV out, primary
display pipe, secondary display pipe) are controlled by a dynamic clock switching
technique that is completely transparent to the software. By turning off the clock to the
block that is idle or not used at that point, the power consumption is significantly
reduced during normal operation. If the clock is needed, it can be restored within one
clock without affecting overall performance of the chip.

Hard Drive and Bay Power Management

Both the internal hard drive and the bay power are controlled by the PIIX4M. These
signals are de-asserted during the Standby state to remove power from the internal hard
drive and whatever module is in the bay.
A timer monitors hard drive activity. It can be set by way of the Setup program to spin
down the hard drive and put it into a low-power state after a selected period of
inactivity. The timer can be disabled or set to one of the predefined timeout periods.

MSIO Super I/O Power Management

The MSIO Super I/O Controller supports a low-power state that can be enabled by
software. It also has internal power management for some of its functions. This internal
power management is enabled at all times. The MSIO is placed into a low-power state
during the Standby and Static Suspend modes.

Audio Power Management

The Maestro 2E has a low-power mode that can be entered from software. This mode is
used in the Standby and Suspend states and when the notebook audio is disabled by
way of the Setup program. There is an AUDIO_PWRDOWN signal that can be used to
put the audio amplifier into a low-power state. The AUDIO_PWRDOWN signal is
generated from the PIIX4M GPO3. This signal is used whenever the controller is
placed into a low-power state as mentioned above.
Power Conservation B-5