#### Plugin: Dell USB-C Dock

## Dell System

Unlike previous Dell USB-C devices, a Dell system is not needed for updating.

## Components

The device contains components the following directly updatable components:

- USB hubs
- MST controller
- Thunderbolt controller
- Embedded controller

This plugin is used to perform the update on the USB hubs as well as the Dell Embedded controller. The USB hubs are updated directly over a USB HID endpoint while the embedded controller is updated using an I2C over HID interface.

The fwupd thunderbolt plugin is used for updating the Titan Ridge controller.

The MST controller is updated through either the DP Aux interface (SynapticsMST plugin) or I2C over HID interface provided by this plugin.

## Device topology

When this plugin is used, devices present in other plugins may be shown in the topology of this dock. This is intentional as this plugin works together with those plugins to manage the flashing of all components.

## Firmware Format

The daemon will decompress the cabinet archive and extract several firmware blobs with an unspecified binary file format.

This plugin supports the following protocol ID:

- `com.dell.dock`
- `com.synaptics.mst`

## GUID Generation

These devices use several different generation schemes, e.g.

- USB Hub1: `USB\VID_413C&PID_B06F&hub`
- USB Hub2: `USB\VID_413C&PID_B06E&hub`
- Embedded Controller: `USB\VID_413C&PID_B06E&hub&embedded`
- Update Level: `USB\VID_413C&PID_B06E&hub&status`
- MST Hub: `MST-panamera-vmm5331-259`
- Thunderbolt Controller: `TBT-00d4b070`
- USB4 Controller: `TBT-00d4b071`

## Update Behavior

All devices will be updated the next time the usb-c plug from the dock is unplugged from the host.

### USB4 Controller

This device will be probed by `dell-dock` plugin over the USB interface, additionally will be probed by `thunderbolt` plugin if thunderbolt hardware is enabled at the host. The primary plugin has been chosen to `dell-dock` for broader supoprt, the device introduced by `thunderbolt` plugin will be default inhibited, before fwupd version 1.8.2 (include), `Update Error` will be seen which is expected.

    USB4 controller in Dell dock:
        Device ID:        ce501f4b2e03e819c525bb9354aa88c03db4f11e
        Summary:          USB4 controller
        Current version:  36.00
        Vendor:           Dell Inc. (THUNDERBOLT:0x00D4, TBT:0x00D4)
        Install Duration: 46 seconds
        Update Error:     firmware update inhibited by [dell_dock] plugin
        GUIDs:            4fb9d92e-2b96-51a7-9ed5-3db156dfcf12 ← THUNDERBOLT\VEN_00D4&DEV_B071
                          bd79ce60-525b-5f39-a3f6-c98c495039ff ← TBT-00d4b071
                          03f008d5-d06a-5d2e-89ca-61f12a8dbf73 ← TBT-00d4b071-controller0-3
        Device Flags:     • System requires external power source
                          • Device stages updates
                          • Updatable
                          • Signed Payload

After version 1.8.2, the device introduced by `thunderbolt` plugin will be default hidden, so only the primary plugin will be seen on the device view.

## Vendor ID Security

The vendor ID is set from the USB vendor, in this instance set to `USB:0x413C`

## Quirk Use

This plugin uses the following plugin-specific quirks:

### DellDockUnlockTarget

The EC argument needed for unlocking certain device usage.

Since: 1.1.3

### DellDockBlobMajorOffset

The offset of the major version number in a payload.

Since: 1.1.3

### DellDockBlobMinorOffset

The offset of the minor version number in a payload

Since: 1.1.3

### DellDockBlobBuildOffset

The offset of the build version number in a payload

Since: 1.1.3

### DellDockBlobVersionOffset

The offset of the ASCII representation of a version string in a payload.

Since: 1.1.3

### DellDockBoardMin

The minimum board revision required to safely operate the plugin.

Since: 1.1.3

### DellDockVersionLowest

The minimum component version required to safely operate the plugin.

Since: 1.1.3

### DellDockBoard*

The board description of a board revision.

Since: 1.1.3

### DellDockInstallDurationI2C

The duration of time required to install a payload via I2C.

Since: 1.1.3

## External Interface Access

This plugin requires read/write access to `/dev/bus/usb`.

## Version Considerations

This plugin has been available since fwupd version `1.2.0`.

## Data flow

      flowchart TD
          subgraph Dell Dock
            I2C([I2C Bus])
            EC
            EC_SPI[(EC\nStorage)]
            USB1
            USB1_SPI[(SPI)]
            USB2
            MST_SPI[(SPI)]
            USB2_SPI[(SPI)]
            MST
            TBT(TBT/USB4)
            TBT_SPI[(SPI)]
          end
          subgraph fwupd Process
            fwupdengine(FuEngine)
            dell_plugin(DellDock\nPlugin)
            tbt_plugin(Thunderbolt\nPlugin)
            usb4_plugin(USB4\nPlugin)
          end
          dell_plugin<--hid proxy-->I2C
          tbt_plugin<--thunderbolt-->TBT
          usb4_plugin<--hid-->TBT
          fwupdengine --- dell_plugin
          fwupdengine --- tbt_plugin
          USB1<-->I2C
          USB2<-.->I2C
          EC<-.->I2C
          TBT<-.->I2C
          MST<-.->I2C
          EC<-.->EC_SPI
          USB1---USB1_SPI
          USB2---USB2_SPI
          MST---MST_SPI
          TBT---TBT_SPI
          I2C~~~EC
          I2C~~~MST
          I2C~~~USB1
          I2C~~~USB2