stand by mode fan still running

[bigallan]

since having work done to my pc by power computering in bedford 2 yrs ago when i select stand my the pc goes into stand by mode but one fan is still running

any ideas?

[bugmonsta]

I was seeking for this information today (in work of course) for a family friend and found these little snippetts from another forum so I hope it helps (if so post back as it may save me a trip at the weekend! )


I recently had this problem when I installed a new mouse and keyboard that used USB. Go into the device manager properties for your mouse and keyboard if they are USB and go into the power management section and verify that "Allow this device to bring the computer out of standby" is not checked. Any USB device that is set up to bring the computer out of standby needs a power source to operate, so the computer leaves the power supply in the normal mode, keeping the fans on, and supplying power to the usb root hub for the device. Maybe that helps some of you? i would have tried looking at the bios settings first even though i have thought of trying to configure the usb devices first. but then it really shows that it's good to read the manual first before doing anything



Windows 98, Windows 98 Second Edition, Windows Millennium Edition, Windows 2000 and Windows XP support two forms of power management. These are APM (Advanced Power Management) and ACPI (Advanced Configuration Power Interface). Although the differences may not seem significant to the end user under Win98, Win98SE and WinME, there are major differences under Windows 2000 and Windows XP.

APM 1.2, the last APM standard, is a a BIOS-based scheme of system power management. It provides CPU and device power management and uses device activity timeouts to determine when to transition devices to low power states.

Unfortunately, APM has a number of problems associated with it.

Every BIOS has its own power management scheme - lacking consistency from one machine to the next. Each BIOS developer must refine and maintain their own APM BIOS code and functionality.
The reason for a suspend is never known. Did the user press the standby button? Did the BIOS think the system was idle? Or is the battery running low? This information is not available but Windows must honour the suspend even if the system is not idle.
The BIOS is unaware what the user is doing and has to second-guess his/her actions by monitoring the interrupts and I/O ports. Sometimes, the BIOS makes a complete mess of it and either suspends when the system isn't idle, or doesn't suspend when it is.
Earlier versions of BIOS APM (1.0 and 1.1) did not provide any system capability information. The only way to determine if the machine supported standby was to attempt to put the system into standby mode. If the BIOS did not support standby, it crashed. BIOS APM 1.2 resolves this problem.
The BIOS knows nothing about USB devices, add-in cards and IEEE 1394 devices. It's possible the BIOS will think the system is idle even if one or more of these devices is/are not.

ACPI was developed to overcome the deficiencies in APM. ACPI (Advanced Configuration and Power Interface) is an open industry specification co-developed by Compaq, Intel, Microsoft, Phoenix, and Toshiba. ACPI establishes industry-standard interfaces for OS-directed configuration and power management on laptops, desktops, and servers.

ACPI evolves the existing collection of power management BIOS code, Advanced Power Management (APM) application programming interfaces (APIs, PNPBIOS APIs, Multiprocessor Specification (MPS) tables and so on into a well-defined power management and configuration interface specification. The specification enables new power management technology to evolve independently in operating systems and hardware while ensuring that they continue to work together.

Unlike APM, ACPI allows the Operating System (instead of the BIOS) to control Power Management (OSPM). The ACPI Standard defines hardware registers (which are implemented in chipset silicon), BIOS interfaces, which include configuration tables, control methods, and motherboard device enumeration and configuration; system and device power states, and the APCI thermal model. The support code provided by the BIOS is not written in the native assembly language of the platform but in AML (ACPI Machine Language). The BIOS does not determine the policies or time-outs for power management or resource management.

Ultimately, all devices in the system can communicate to each other about usage and is controlled from the operating system. The operating system has the most knowledge on a running system's state, and so is in the best position to perform power management.

There are 4 device states under APM: Enabled, Standby, Suspend and Off.

ACPI's device states are extended, with 4 major global states: Working (S0), Sleeping (S1-S3), Soft-Off (S4), and Mechanical-Off (S5). Sleeping is further broken down into 3 substates.

The ACPI BIOS tables define what these states mean for individual devices, and the operating system determines when to move a device, or even the entire system, from one state to another.

The ACPI-compatible OS mainly acts as a swap manager that swap the computer to different state based on the information collected. A transition from one state to another is first started with the OSPM system code which instructs the OS kernel for the specific state transition. After the kernel receives the instruction, it'll ask the appropriate device driver to perform the operation. Response from the operation will be passed back to the OSPM from the kernel. This process will proceed in hierarchical order until all devices and components reach the specified state.

In addition to enabling operating-system-directed power management, provides a generic system event mechanism for Plug and Play and an operating-system-independent interface for configuration control. ACPI leverages the Plug and Play BIOS data structures while providing a processor architecture-independent implementation that is compatible with Windows operating systems.

A Plug and Play system requires the combined interaction of the personal computer's BIOS, hardware components, device drivers, and operating system software. The basic system board implementation and BIOS support required for Plug and Play support under Windows XP and Windows 2000 are defined in the ACPI specification. Windows XP, Windows 2000 and Windows 98 use this specification as the basis for their Plug and Play and OnNow architecture.

The ACPI specification defines a new interface between the operating system and the personal computer's Plug and Play and power management features. ACPI specifies a register-level interface to core Plug and Play and power management functions and defines a descriptive interface for additional hardware features. This gives system designers the ability to implement a range of Plug and Play and power management features with different hardware designs while using the same operating-system driver.

Under Windows 98, Windows 98 Second Edition and Windows Millennium Edition, ACPI is needed to support PCI Bus IRQ Steering. Windows can dynamically "steer" or assign IRQs to PCI devices, giving Windows the flexibility to reprogram PCI IRQs when it rebalanced Plug and Play resources.

An IRQ Holder for PCI Steering may be displayed when you view the System Devices branch in Device Manager. An IRQ Holder for PCI Steering indicates that an IRQ has been programmed to PCI mode and is unavailable for ISA devices, even if no PCI devices are currently using the IRQ. To view IRQs that are programmed for PCI-mode:

1. Click Start, point to Settings, click Control Panel, and then double-click System.
   
2. Click the Device Manager tab.
   
3. Double-click to expand the System Devices branch.
   
4. Double-click the IRQ Holder for PCI Steering that you want to view, and then click the Resources tab.

Under Windows 2000 and Windows XP, the ramifications for ACPI's Plug and Play are more extensive, and provide the following:
Automatic and dynamic recognition of installed hardware. This includes initial system installation, recognition of Plug and Play hardware changes that occur between system boots, and response to run-time hardware events, such as dock or undock and device insertion or removal.
Hardware resource allocation (and reallocation). Drivers for Plug and Play devices do not assign their own resources. Instead, the required resources for a device are identified when the device is enumerated by the operating system. The Plug and Play Manager retrieves the requirements for each device during resource allocation. Based on the resource requests that each device makes, the Plug and Play Manager assigns the appropriate hardware resources, such as I/O ports, interrupt requests (IRQs), direct memory access (DMA) channels, and memory locations. The Plug and Play Manager reconfigures resource assignments when needed, such as when a device is added to the system, and requests resources that are already in use.
Loading of appropriate drivers. The Plug and Play Manager determines which drivers are required to support a particular device and loads those drivers.
An interface for driver interaction with the Plug and Play system. The interface consists primarily of I/O routines, Plug and Play I/O request packets (IRPs), required driver entry points, and information in the registry.
Interaction with power management. One of the key features of both Plug and Play and power management is dynamic handling of events. The addition or removal of a device is an example of such a dynamic event, as is the ability to awaken a device or put it to sleep. Plug and Play and power management both use WDM-based functions and have similar methods for responding to dynamic events.
Registration for device notification events. Plug and Play enables user-mode code to register for and be notified of certain Plug and Play events. The RegisterDeviceNotification routine allows callers to filter exactly the class or device for which they want to receive notification. This can be specific, such as a file system handle, or general, such as a class of devices. Legacy Windows NT notification methods continue to work as before.

Certainly not the least noticed with ACPI is the infamous allocation of all peripheral devices to a single IRQ seen with the ACPI Hardware Abstract Layer and the inability to change the IRQ allocations. Windows 2000 and Windows XP both do this because of the more complex hardware schemas they have to support, such as IO-APICs, multiple root PCI buses, multiple-processor systems, and so on. Rebalancing becomes risky when you are dealing with these hardware schemas, and will not be implemented in Windows 2000 and Windows XP except for very specific scenarios. However, PCI devices are required to be able to share IRQs. The ability to share IRQs should not prevent any hardware from working in general.

Windows 2000 and Windows XP institute a rigorous test to determine if the ACPI Hardware Abstraction Layer (HAL) is installed. An ACPI system consists of a series of ten tables. These ten tables define which devices are present on the system and what their capabilities are as they relate to configuration and power management. These tables are built by the system BIOS at boot. When the system boots, it looks for specific entries contained in two of these tables (the Fixed ACPI Description table [FACP] and the Root System Description table [RSDT]) to determine if the system is ACPI compliant. This information is extracted from these tables in the form of an OEM ID, OEM TABLE ID, OEM REVISION, and CREATOR REVISION. If these tables are not present or the information contained in the descriptors above is invalid, the system is assumed to be non-ACPI and the Standard legacy HAL is installed.

If your system has been installed with the Standard HAL, you can still enable APM (although APM and ACPI are mutually exclusive). APM support allows Windows 2000 and Windows XP to perform a soft shutdown of your system. To enable APM:

1. Click Start, point to Settings, click Control Panel, and then double-click Power Options.
   
2. Click on the APM tab.
   
3. Check the Enable APM check box.

For further information on ACPI, please see the following articles:

Intel - Instantly Available Technology - ACPI

Phoenix Technologies - Phoenix Platformware - ACPI

PCForrest | BIOS | APM - also ACPI, OnNow And SIPC

FAQ for ACPI and Microsoft Operating Systems (withdrawn)

Understanding ACPI

ACPI

How Windows determines ACPI compatibility

Windows and Advanced Power Management (APM) Support

Microsoft Technet: ACPI Overview

Windows 2000 Professional Documentation

Plug and Play for Microsoft Windows 2000

Description of PCI Bus IRQ Steering

[criminalben]

Try using hibernate instead of standby. AFAIK because standby is still supplying power to the RAM it needs to leave a fan or two running to cool itself. You can find hibernate in power options in control panel.

[venkata]

Some fans are 3 wie connectors, some are 2. Could this be it?