fwupd/plugins/synaptics-mst/README.md
Richard Hughes 078beafb2d Add a new internal flag to opt-in to GUID matching
It is far too easy to forget to set FWUPD_DEVICE_FLAG_NO_GUID_MATCHING for new
plugins, and without it it all works really well *until* a user has two devices
of the same type installed at the same time and then one 'disappears' for hard
to explain reasons. Typically we only need it for replug anyway!

Explicitly opt-in to this rarely-required behaviour, with the default to just
use the physical and logical IDs. Also document the update behavior for each
plugin to explain why the flag is being used.

This allows you to have two identical Unifying plugged in without one of them
being hidden from the user, at the same time allowing a HIDRAW<->USB transition
when going to and from bootloader and runtime modes.

This removes the workaround added in 99eb3f06b6.

Fixes https://github.com/fwupd/fwupd/issues/2915
2021-02-25 15:47:25 +00:00

2.8 KiB

Synaptics MST

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-$(device_kind)-$(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)

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: e94cb37b34

libsmbios

At compilation time and runtime you will need libsmbios_c version 2.3.0 or later

If you don't want or need this functionality you can use the --disable-dell option.

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*.