Plugin: Synaptics MST

Introduction

This plugin supports querying and flashing Synaptics MST hubs used in Dell systems and docks.

Firmware Format

The daemon will decompress the cabinet archive and extract a firmware blob in an unspecified binary file format.

This plugin supports the following protocol ID:

com.synaptics.mst

GUID Generation

These devices use custom GUID values, e.g.

MST-$(board-ID)
MST-$(device_kind)-$(chip-ID)-$(board-ID)
MST-$(device_kind)-$(board-ID)
MST-$(device_kind)

Please refer to the plugin source for more details about how the GUID is constructed for specific hardware.

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.

Vendor ID Security

The vendor ID is set from the PCI vendor, for example set to DRM_DP_AUX_DEV:0x$(vid)

Quirk Use

This plugin uses the following plugin-specific quirks:

Flags:manual-restart-required

The device must be restarted manually after the update has completed.

Flags:ignore-board-id

Ignore board ID firmware mismatch.

Requirements

(Kernel) DP Aux Interface

Kernel 4.6 introduced an DRM DP Aux interface for manipulation of the registers needed to access an MST hub. This patch can be backported to earlier kernels: https://github.com/torvalds/linux/commit/e94cb37b34eb8a88fe847438dba55c3f18bf024a

Usage

Supported devices will be displayed in # fwupdmgr get-devices output.

Here is an example output from a Dell WD15 dock:

Dell WD15/TB16 wired Dock Synaptics VMM3332
  Guid:                 653cd006-5433-57db-8632-0413af4d3fcc
  DeviceID:             MST-1-1-0-0
  Plugin:               synaptics_mst
  Flags:                allow-online
  Version:              3.10.002
  Created:              2017-01-13
  Modified:             2017-01-13
  Trusted:              none

Payloads can be flashed just like any other plugin from LVFS.

Supported devices

Not all Dell systems or accessories contain MST hubs. Here is a sample list of systems known to support them however:

Dell WD15 dock
Dell TB16 dock
Dell TB18DC
Latitude E5570
Latitude E5470
Latitude E5270
Latitude E7470
Latitude E7270
Latitude E7450
Latitude E7250
Latitude E5550
Latitude E5450
Latitude E5250
Latitude Rugged 5414
Latitude Rugged 7214
Latitude Rugged 7414

External Interface Access

This plugin requires read/write access to /dev/drm_dp_aux*.

Version Considerations

This plugin has been available since fwupd version 1.3.6.

Data Flow

  flowchart LR
      subgraph MST Controller
        MST(Controller)
        SPI[(SPI)]
      end
      subgraph Kernel
        gpu(GPU\ndriver)
      end
      subgraph fwupd Process
        fwupdengine(FuEngine)
        mst_plugin(Synaptics MST\nPlugin)
      end
      fwupdengine-->mst_plugin
      mst_plugin<--/dev/drm_dp_aux-->gpu
      gpu<--DDC/I2C-->MST
      MST---SPI

Owners

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

Apollo Ling: ApolloLing