PAGP_SET_RATE callback function

The AgpSetRate function reprograms the data transfer rate of the AGP chipset.

Syntax


PAGP_SET_RATE AgpSetRate;

BOOLEAN APIENTRY AgpSetRate(
  _In_ PVOID HwDeviceExtension,
  _In_ ULONG AgpRate
)
{ ... }

Parameters

HwDeviceExtension [in]

Pointer to the miniport driver's device extension.

AgpRate [in]

Specifies the transfer rate to be set. This value can be one of the following:

ValueMeaning

VIDEO_AGP_RATE_1X

Single speed (66 Mhz)

VIDEO_AGP_RATE_2X

Two times single speed

VIDEO_AGP_RATE_4X

Four times single speed

VIDEO_AGP_RATE_8X

Eight times single speed

 

Return value

AgpSetRate returns TRUE if it was successful in changing the transfer rate; otherwise, it returns FALSE.

Remarks

This function is available in Microsoft Windows XP and later.

The transfer rate set by the AgpSetRate function is persistent across changes in power state. The video miniport driver does not have to reset the AGP transfer rate when it changes from a low power state to a full power state. For information about change of power state, see HwVidSetPowerState.

The AgpSetRate function can be used to change an AGP chipset's data transfer rate to any of the rates shown in the preceding table, as long as that transfer rate has not been explicitly eliminated in the INF file that loaded the display driver. For more information, see Display INF File Sections.

Requirements

Target platform

Desktop

Version

Available in Windows 2000 and later versions of the Windows operating systems.

Header

Videoagp.h (include Video.h)

IRQL

PASSIVE_LEVEL

See also

VIDEO_PORT_AGP_INTERFACE_2

 

 

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