GIMX PS4 support – status 9

I pushed gimx-config & gimx-fpsconfig updates in the git repository.

In gimx-config, there is a new “Type” menu that allows to change the controller type. Setting the right controller type allows to display controller-specific axis and button names.


ps4 buttons

ps4 axes

I will now work on merging gimx-serial and gimx-bluetooth in a unified launcher that will also support the PS4.

GIMX PS4 support – status 8

I pushed touchpad support in the git repository.
People that already cloned the source can run the following commands to update GIMX:

git pull
make clean
sudo make install

I wrote a configuration for KillZone Shadow Fall that showcases this touchpad support. It can be downloaded via gimx-serial or gimx-bluetooth, using the “Help>Get Configs” menu (the file is named PS4_KillZoneShadowFall.xml). Key ‘f’ controls finger presence and the mouse axes control finger coordinates.

I will now work on updating the GUIs.

GIMX PS4 support – status 7

I managed to send touchpad inputs using a button and two axes (a mouse). The button controls the finger presence, and the axes control the finger coordinates. This allows me to control the drone modes in Killzone! The source code needs some refactoring before landing into the git repository.

A few products (venom x, xim4, titan) have announced PS4 support over USB. They are mixing the USB transfers from the Hori pad and from the DS4. They all lack touchpad support, and there is no evidence touchpad inputs can work over USB.

GIMX PS4 support – status 5

As it may take some time before everything can be run from a GUI, I wrote a few instructions for anyone wanting to try early PS4 support in GIMX.

Those instructions can be read on the wiki.

It may seem quite complex, but once the pairing is done, starting GIMX is as simple as running a single command in a terminal.

GIMX is only able to run at 100Hz for now, I’ll try to improve this later. I’m currently working on adding touchpad support.

GIMX PS4 support – status 4

GIMX is now able to talk to a PS4 🙂

I worked on adding bluetooth proxy capabilities to GIMX. Before connecting to the PS4, GIMX waits for a Dualshock 4 to connect. Then it forwards HID control transfers, and it directly handles SDP and HID interrupt transfers.

I had to solve an issue with the SDP: the DS4 sends a 708-byte service attribute search response, which is larger than the 672-byte outgoing L2CAP MTU. As the Linux kernel rightly refuses to send L2CAP packets larger than the outgoing L2CAP MTU, I had to go to a lower level in the bluetooth stack so as to directly send ACL packets.

I now have to see how to achieve a high packet rate (800 packets per second). It seems a single bluetooth dongle will not be enough to handle twice this packet rate (from the DS4 + to the PS4).

GIMX PS4 support – status 3

I kept working on the bluetooth protocol and I found that there is an authentication process carried over the HID control channel. It consists in a sequence of bluetooth transfers that lasts about 30 seconds, and that restarts after 30 seconds. If this sequence fails 8 times in a row, the PS4 stops taking inputs.

This means GIMX will require a genuine Dualshock 4 to control a PS4. It will have to stay connected as the authentication sequence is periodical.

I also worked on writing an AVR USB firmware that can emulate the pairing procedure of the Dualshock 4. It allows to pair any bluetooth device address with the PS4. I spent more time than I thought on this because of a problem in the USB transfers that only seems to happen with the PS4 as USB host. Frank from eleccelerator helped me to fix this issue.

This firmware is designed to work with a tool called ds4tool that can do the following tasks:

  • read the bluetooth device address from a real or emulated DS4
  • read the PS4 address from a real or emulated DS4
  • write the PS4 address and the link key of a real or emulated DS4
  • write the bluetooth device address of an emulated DS4
  • read the link key from an emulated DS4