EVT_IDD_CX_MONITOR_I2C_TRANSMIT callback function (iddcx.h)

Article
02/22/2024

EVT_IDD_CX_MONITOR_I2C_TRANSMIT is called by the OS to return data received to an I2C device in a monitor.

Syntax

EVT_IDD_CX_MONITOR_I2C_TRANSMIT EvtIddCxMonitorI2cTransmit;

NTSTATUS EvtIddCxMonitorI2cTransmit(
  [in] IDDCX_MONITOR MonitorObject,
  [in] const IDARG_IN_I2C_TRANSMIT *pInArgs
)
{...}

Parameters

[in] MonitorObject

A handle used by the OS to identify the monitor to return I2C data to.

[in] pInArgs

Input arguments used by EVT_IDD_CX_MONITOR_I2C_TRANSMIT.

Return value

(NTSTATUS) If the operation is successful, the callback function must return STATUS_SUCCESS, or another status value for which NT_SUCCESS(status) equals TRUE. Otherwise, an appropriate NTSTATUS error code.

Remarks

EVT_IDD_CX_MONITOR_I2C_TRANSMIT is responsible for signaling the I2C start condition, sending the I2C address, sending the data in the buffer, checking for acknowledgments from the receiver, and signaling the stop condition. For details about the I2C bus, see the I2C Bus Specification, published by Philips Semiconductors. The specification defines a protocol for initiating I2C communication, reading and writing bytes over the I2C data line, and terminating I2C communication.

EVT_IDD_CX_MONITOR_I2C_TRANSMIT is required to transmit data to an I2C device that has address 0x6E but is permitted to refuse to transmit data to any I2C device that has a different address.

EVT_IDD_CX_MONITOR_I2C_TRANSMIT is permitted to block if another part of the display driver or graphics hardware is using the specified monitor's I2C bus. It is also permitted to block if the display driver is using the I2C bus to send or receive High-bandwidth Digital Content Protection (HDCP) data. EVT_IDD_CX_MONITOR_I2C_TRANSMIT has a 5 second timeout and must complete in that time limit.

If the display adapter supports HDCP, EVT_IDD_CX_MONITOR_I2C_TRANSMIT must refuse to send data to an I2C device if the device has an I2C address that is used by HDCP. EVT_IDD_CX_MONITOR_I2C_TRANSMIT must never transmit data to an I2C device on the display adapter. That is, this function can transmit data to an I2C device in a monitor that is connected to the display adapter, but not to an I2C device that is on the display adapter itself.

Requirements

Requirement	Value
Minimum supported client	Windows 10
Minimum supported server	Windows Server 2016
Target Platform	Windows
Header	iddcx.h
IRQL	requires_same

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