Microsoft KB Archive/190525

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PRB: ACPI System Fails to Hibernate Due to Display Device

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Q190525

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The information in this article applies to:


 * Microsoft Win32 Device Driver Kit (DDK) Windows 98

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SYMPTOMS
A Windows 98 ACPI system might fail to hibernate (transition to S4). The debug build of configmg.vxd displays a debug output that lists any devices that failed the transition to S4. The display device might be listed as the device preventing S4.

CAUSE
In Windows 98 ACPI systems, the display device miniVDD should support OnNow by responding to power state commands and by providing information on what power states are supported by the hardware device. The miniVDD GET_ADAPTER_POWER_STATE_CAPS function returns a bitmask indicating the power states supported by the display adapter. This function should return with the CM_POWERSTATE_D3 flag set in order to support S4.

RESOLUTION
To work around display drivers that do not support OnNow, you need to make a registry entry in the device's software branch named "REPOST" to allow the display device to transition to D3 and the system to hibernate. The "REPOST" registry entry should be placed in HKLM/System/CurrentControlSet/Services/Class/Display/XXXX/Default, where XXXX is a number, and it should be set to a STRING value of 1.

STATUS
This behavior is by design.