How to achieve AUX communication via the DP interface for the Windows system

Question

How to achieve AUX communication via the DP interface for the Windows system

PENG TONG 90

Background:

The current Intel Aux communication technology route we support is based on the official Intel documentation IGCL. The official also mentioned that it is only applicable to Alder Lake-P or higher platforms. Alder Lake was launched by Intel in 2022. The old motherboard is Intel H81 (Lynx Point), and it is equipped with the Celeron G1820 processor launched by Intel in 2013. The hardware of the motherboard does not meet the conditions for using IGCL. Therefore, our current Aux upgrade plan should not be applicable to this old motherboard.

Qustion:

For Intel H81 (Lynx Point), and it is equipped with the Celeron G1820 processor + Intel HD Graphics (GPU), how to achieve AUX communication via the DP interface

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Answer 1

Hi PENG TONG

Based on Intel's documentation, IGCL support for DisplayPort AUX access is intended for newer Intel graphics platforms and drivers (such as Alder Lake-era systems and later). On an Intel H81 (Lynx Point) system with a Celeron G1820 and Intel HD Graphics, the DisplayPort AUX channel is used internally by the graphics hardware for tasks such as link training and EDID/DPCD communication, but there is no publicly documented Intel API equivalent to IGCL that exposes arbitrary AUX transactions to user applications on this older platform.

In short, while the hardware likely uses the AUX channel internally if a DP output is present, direct AUX communication through a supported Intel software interface is generally not available on the H81/G1820 platform.

You can certainly ask here, but this question is more about Intel graphics hardware, DisplayPort AUX communication, and Intel's Graphics Control Library (IGCL) than it is about Windows itself. The Microsoft Q&A forum is generally focused on Windows and Microsoft technologies, while low-level GPU interfaces and Intel-specific capabilities are typically handled by Intel's developer and graphics support communities.

For the best chance of getting a definitive answer on whether DisplayPort AUX communication can be exposed on an H81 (Lynx Point) platform with a Celeron G1820 and Intel HD Graphics, I would recommend reposting the question on Intel's forums, where Intel engineers and graphics developers may be able to clarify the hardware and driver limitations of that platform.

I hope this helps point you to the most appropriate support channel.