FwupdPlugin – 1.0: Plugin: Mediatek Display Controller
Description: Reference for FwupdPlugin-1.0: Plugin: Mediatek Display Controller

## Introduction

This plugin updates the firmware of DisplayPort device made by Mediatek.

These devices communicate over I²C, via the DisplayPort aux channel. Devices are declared by kernel graphic driver, and queried with custom DDC/CI command to ensure the target devie.

This plugin polls every drm dp aux device to find out the `i2c-dev` that is being used for DDC/CI communication. Devices should respond to a vendor specific command otherwise the display controller is ignored as unsupported.

## Firmware Format

The daemon will decompress the cabinet archive and extract a firmware blob in an unspecified binary file format, which is written to the partition of the device flash that is not currently running.

This plugin supports the following protocol ID:

- `com.mediatek.scaler`

## GUID Generation

Devices use instance ID that is composed of `Subsystem ID`, `Subsystem Model`, and the `Hardware Version`. The hardware version is read from the device.

- `DISPLAY\VID_1028&PID_0C88&HWVER_2.1.2.1`
- `DISPLAY\VID_1028&PID_0C8A&HWVER_2.1.2.1`

## Update Behavior

The firmware is deployed when the device is in normal runtime mode, and the device will reset when the new firmware has been written. On some hardware the MST device may not enumerate if there is no monitor actually plugged in.

## Quirk Use

This plugin does not use quirks.

## Vendor ID security

The vendor ID is set from the PCI vendor, for instance `PCI:0x1028` on Dell systems.

## External Interface Access

This plugin requires access to i2c buses associated with the specified DisplayPort aux channel, for instance `/dev/i2c-5` and `/dev/drm_dp_aux3`. Note that the device number changes in various situations.

## Version Considerations

This plugin has been available since fwupd version `1.9.6`.

## Owners

Anyone can submit a pull request to modify this plugin, but the following people should be consulted before making major or functional changes:

- Crag Wang: `CragW`
- Greg Lo: `GregLo007`