Power Management - HP Compaq dc7900 USDT Technical Reference Manual

System Support
Level 0—Cover removal indication is essentially disabled at this level. During POST, status bit is
cleared and no other action is taken by BIOS.
Level 1—During POST the message "The computer's cover has been removed since the last
system start up" is displayed and time stamp in CMOS is updated.
Level 2—During POST the "The computer's cover has been removed since the last system start
up" message is displayed, time stamp in CMOS is updated, and the user is prompted for the
administrator password. (A Setup password must be enabled in order to see this option).
Smart Cover Lock (Optional)
The SFF and CMT systems support an optional solenoid-operated locking bar that, when
activated, prevents the cover (hood) from being removed. The GPIO ports 44 and 45 of the SIO
controller provide the lock and unlock signals to the solenoid. A locked hood may be bypassed
by removing special screws that hold the locking mechanism in place. The special screws are
removed with the Smart Cover Lock Failsafe Key.

4.5.2 Power Management

These systems provide baseline hardware support of ACPI- and APM-compliant firmware and
software. Key power-consuming components (processor, chipset, I/O controller, and fan) can be
placed into a reduced power mode either automatically or by user control. The system can then
be brought back up ("wake-up") by events defined by the ACPI 2.0 specification. The ACPI
wake-up events supported by this system are listed as follows:
ACPI Wake-Up Events
ACPI Wake-Up Event
Power Button
RTC Alarm
Wake On LAN (w/NIC)
PME
Serial Port Ring
USB
Keyboard
Mouse
4-12
Table 4-7.
System Wakes From
Suspend or soft-off
Suspend or soft-off
Suspend or soft-off
Suspend or soft-off
Suspend or soft-off
Suspend only
Suspend only
Suspend only
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