Specifications

AMD Geode™ GeodeROM Functional Specification 227
System Management Mode Software
32087C
15.11.6 MSG_EVENT
MSG_EVENT is the most common message. When a registered event occurs, this message is sent to the VSM with the
highest priority. If a VSM handles the event, the VSM does not have to do anything explicitly to notify the System Manager.
However, if a VSM chooses not to handle the event, it must invoke the SYS_PASS_EVENT system call (in the Geode GX1
processor only) to give other VSMs that have registered for the same event an opportunity to handle it. If no VSM handles
the event (all registered VSMs invoked the SYS_PASS_EVENT system call), an error is signaled. See Section 15.4
“Events” on page 213.
• Parameter0: Event code
• Parameter1: Dependent on event
• Parameter2: Dependent on event
• Parameter3: Dependent on event
• Parameter4: Dependent on event
15.11.7 MSG_QUEUE_OVERFLOW
The System Manager always reserves one message queue entry for this message. If an event occurs that would overflow
the message queue, a MSG_QUEUE_OVERFLOW message is sent instead of the original message. The original mes-
sage code is passed in Parameter0. If any more events occur before the MSG_QUEUE_OVERFLOW message is
retrieved, those events are discarded and an error is signaled.
This message is primarily designed to notify a VSM of an event overrun. In many cases, nothing can be done about this
error condition. However, some VSMs are able to change their behavior to alleviate the condition. For example, an audio
VSM can reduce the audio sampling rate.
• Parameter0: Event code
15.11.8 MSG_WARM_BOOT
This message is sent to each VSM immediately before the system is warm booted. VSMs should respond to this message
by preparing the related hardware. This typically means ensuring that no more SMIs are generated by the hardware. For
example, the audio VSM should disable the audio hardware and wait for the output FIFO to empty. The video VSM should
turn off vertical retrace SMI.
• No Parameters
15.11.9 MSG_SET_POWER_MODE (Geode GX processor only)
This message is broadcast to all VSMs when the power management mode changes. If a VSM power manages one or
more devices, it should respond appropriately to this message. Typically, the ACPI VSM manages ACPI mode exclusively
and the APM manages APM mode exclusively. Legacy mode is managed at the discretion of each VSM. If PM is disabled,
the VSM should return any of the devices it manages to Full Power and cease to perform PM.
Power management mode changes may occur in several ways:
• APM connect/disconnect
• ACPI enable/disable
• BIOS setting the PM default mode via virtual register VRC_PM::POWER_MODE
Parameter0: New mode
— 0000 = Disabled
— 0001 = Legacy PM
— 0002 = APM
— 0003 = ACPI