PAGP_SET_RATE callback function (videoagp.h)

Article
02/22/2024

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

Syntax

PAGP_SET_RATE PagpSetRate;

BOOLEAN PagpSetRate(
  [in] IN PVOID HwDeviceExtension,
  [in] IN ULONG AgpRate
)
{...}

Parameters

[in] HwDeviceExtension

Pointer to the miniport driver's device extension.

[in] AgpRate

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

Value	Meaning
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

Requirement	Value
Minimum supported client	Available in Windows 2000 and later versions of the Windows operating systems.
Target Platform	Desktop
Header	videoagp.h (include Video.h)
IRQL	PASSIVE_LEVEL