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IDE_CHANNEL_ENABLED callback function (irb.h)

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The AtaControllerChannelEnabled miniport driver routine indicates whether the specified channel is enabled.

Note

The ATA port driver and ATA miniport driver models may be altered or unavailable in the future. Instead, we recommend using the Storport driver and Storport miniport driver models.

Syntax

IDE_CHANNEL_ENABLED IdeChannelEnabled;

ATA_CHANNEL_STATE IdeChannelEnabled(
  PVOID ControllerExtension,
  ULONG Channel
)
{...}

Parameters

ControllerExtension

[in] A pointer to the controller extension.

Channel

[in] The channel to enable.

Return value

AtaControllerChannelEnabled returns an enumerator value of type ATA_CHANNEL_STATE, which can have any of the following values:

Return code Meaning
ChannelStateEnabled Indicates that the specified channel is enabled.
ChannelStateDisabled Indicates that the specified channel is disabled.
ChannelStateUnKnown Indicates that the state of the channel could not be determined.

Remarks

The following sequence describes how the miniport driver and the port driver interact to determine which controller channels are enabled:

  1. The port driver calls the miniport driver's AtaAdapterControl routine with control action IdeStart.

  2. While the miniport driver processes the AtaAdapterControl routine with control action IdeStart, it initializes the NumberOfChannels member of IDE_CONTROLLER_CONFIGURATION to indicate the number of channels that are enabled.

  3. After the AtaAdapterControl routine returns, the port driver calls AtaControllerChannelEnabled one time for every NumberOfChannels specified in the ControllerConfiguration structure that are returned by AtaAdapterControl.

This routine should not have steps that are critical to the operation of the controller. There are situations, such as during a crashdump operation, where this function will not be called at all. Additionally, this function is not called when a channel is restarted, only when PCIIDEx responds to a QueryDeviceRelations IRP.

AtaControllerChannelEnabled is an optional routine. If the miniport driver does not implement this routine, the port driver will load a default handler. If the port driver loads a default handler, all channels that are specified by NumberOfChannels in the ControllerConfiguration structure that is returned by AtaAdapterControl when handling an IdeStart action are assumed to be enabled. This routine enables PCIIDEx to load the ATA port driver for only the channels enabled. Doing this allows for sparse channel support (for example, channel 0, channel 1, channel 3, channel 4, and channel 6, but not channel 2 and channel 5).

Requirements

Requirement Value
Target Platform Desktop
Header irb.h (include Irb.h)

See also

IDE_CONTROLLER_CONFIGURATION