기술 문서

Power Button Functionality On The Latitude CP - Technical Tip - 152493


Power Button Functionality On The Latitude™ CP

The Latitude CP power switch is similar to previous products with some minor, but important modifications. The most significant modification is operating system notification. This feature will, in the future, be required by Microsoft to obtain certification under the PC 97 and ACPI specifications. These specifications entail that the system BIOS must notify the operating system that the power switch has been pressed and must allow the OS to follow its standard shutdown procedure prior to actual removal of system power. The OS will have the capability of delaying or even aborting the power down sequence until the operating system shutdown sequence or any other necessary processes have been completed.

Because of this new "power down authorization" principal, there arises some potential for additional problems to occur. If, for example, the operating system is somehow unable to respond to the system BIOS request for power down, a mechanism must be put in place to allow the user to override the OS shutdown authorization requirement.

For the Latitude CP, the power down override will be achieved by depressing the power switch for 4 seconds. If the system BIOS detects that the power switch has been active for a continuous 4 second duration, the system will immediately and unconditionally power down.

Please note: As of the date of this specification, Microsoft has not finalized or published the callback mechanism that must be implemented in the system BIOS to support this feature under any non-ACPI operating systems, including Windows 95. Please note that this feature is not adequately documented in the ACPI specification). Because of this, the OS notification will be supported on the Windows 98 ACPI implementation only.

During operation on non-ACPI operating systems, the power switch behavior may be generalized by the following two conditions: When the system is running in the normal operational (full on) state, depressing the power switch will cause the system to power down. When the system is currently operating in any power management state in which the LCD display is blank (standby, suspend, or suspend-to-disk), depressing the power switch will cause the system to return to the normal operational (full on) state.



 


Quick Tips content is self-published by the Dell Support Professionals who resolve issues daily. In order to achieve a speedy publication, Quick Tips may represent only partial solutions or work-arounds that are still in development or pending further proof of successfully resolving an issue. As such Quick Tips have not been reviewed, validated or approved by Dell and should be used with appropriate caution. Dell shall not be liable for any loss, including but not limited to loss of data, loss of profit or loss of revenue, which customers may incur by following any procedure or advice set out in the Quick Tips.

문서 ID: SLN68889

최종 수정일: 11/13/2010 12:00 AM


이 문서 평가하기

정확함
유용함
이해하기 쉬운
이 문서가 도움이 되셨나요?
지원 미지원
피드백을 보내 주십시오.
의견에는 <>()\와 같은 특수 문자를 사용할 수 없습니다.
죄송합니다. 현재 피드백 시스템은 사용하실 수 없습니다. 잠시 후에 다시 시도하십시오.

피드백을 보내주셔서 감사합니다.