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KsDeviceGetBusData function (ks.h)

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The KsDeviceGetBusData function reads data from the bus where the given AVStream device resides.

Syntax

KSDDKAPI ULONG KsDeviceGetBusData(
  [in] PKSDEVICE Device,
  [in] ULONG     DataType,
  [in] PVOID     Buffer,
  [in] ULONG     Offset,
  [in] ULONG     Length
);

Parameters

[in] Device

A pointer to the KSDEVICE structure representing the given AVStream device for which data from the bus should be read.

[in] DataType

This parameter indicates the type of bus data to be read. Zero corresponds to configuration space. For further information, see the discussion of WhichSpace in the reference page for IRP_MN_READ_CONFIG.

[in] Buffer

A pointer to a buffer that receives the data read from the bus. Must be at least as large as Length.

[in] Offset

This parameter contains the byte offset in the space specified by DataType from which data is read.

[in] Length

This parameter specifies the number of bytes to read into Buffer.

Return value

KsDeviceGetBusData returns the number of bytes actually read from the bus. If an errors occurs, this value is zero.

Remarks

Depending on the driver for the bus where the specified device resides, there are two possible behaviors and restriction sets on this function. If the given bus driver supports the bus interface standard (usually PCI), call this function at either IRQL = PASSIVE_LEVEL or DISPATCH_LEVEL. After such a call, KsDeviceGetBusData returns the actual number of bytes read from the requested space. If, however, the given bus driver does not support the bus interface standard, then AVStream communicates with the bus driver through IoCallDriver. Note that this restricts use of KsDeviceGetBusData to IRQL = PASSIVE_LEVEL and also means that the return value is either 0, in the case of failure, or equal to Length if data acquisition was successful.

To ensure compatibility, minidriver writers may want to restrict use of KsDeviceGetBusData to IRQL = PASSIVE_LEVEL.

Requirements

Requirement Value
Minimum supported client Available in Microsoft Windows XP and later operating systems and DirectX 8.0 and later DirectX versions.
Target Platform Universal
Header ks.h (include Ks.h)
Library Ks.lib
IRQL PASSIVE_LEVEL (See Remarks section)

See also

IoCallDriver

KsDeviceSetBusData