To speed up my development, I’ll try using the dummy_hcd kernel module, which allows to emulate an OTG port connected to the computer.
dummy_hcd is missing on my GNU/Linux distribution (Linux Mint 17.3), so I had to build it myself:
apt-get source linux-image-`uname -r`
cp /boot/config-`uname -r` .config
cp /usr/src/linux-headers-`uname -r`/Module.symvers .
# select → Device Drivers → USB support → USB Gadget Support → USB Peripheral Controller → Dummy HCD
make -j 4 M=drivers/usb/gadget
sudo cp drivers/usb/gadget/udc/dummy_hcd.ko /lib/modules/`uname -r`/kernel/drivers/usb/gadget/udc/
sudo depmod -a
Adding the following line to /etc/fstab makes it easier to mount the gadget file system:
gadget /dev/gadget gadgetfs noauto,user,group 0 0
Creating a udev rule in /etc/udev/rules.d/99-gadgetfs.rules allows to automatically mount the gadget filesystem when dummy_hcd is loaded:
In recent weeks, I have been working on serialusb, a cheap USB proxy for input devices.
This tool can act as a USB proxy using the well-known DIY USB adapter.
Combined with usbmon and wireshark, it allows to generate and inspect USB captures.
Read the github project page to learn about the capabilities, the limitations, and the usage instructions of serialusb.
I’ve tested it successfully with the following hosts and devices:
PC + Logitech G502 gaming mouse
PC + Dell USB keyboard
PC + Logitech Driving Force GT
PC + Logitech RumblePad 2
PS3 + Logitech Driving Force GT
PC or PS3 + Dualshock 3
PC or PS4 + Hori Pad Fps plus
PC or Xbox 360 + Xbox 360 controller
PC or Xbox One + Xbox One controller
If you have a DIY USB adapter and any of the following host + device combination, please consider making a USB capture and send it to me:
Xbox One + Logitech G920
Xbox One + Xbox One controller with 3.5mm stereo headset jack (USB PID = 0x02dd)
This release adds force feedback support for the G27 wheel emulation (#307), fixes pedal issues when using the i386 version (#358), and fixes mouse to axis translation defects when using a GPP/Cronus/Titan device (#360).
This release improves force feedback management in case of transmission errors (#357). It includes USBDK 1.0.7 which fixes issues with some USB host controllers (#345) and makes GIMX i386 able to run on 64bit Windows (#343).
In a previous post I explained that I built a cross-platform (GNU/Linux and Windows) HID communication layer with asynchronous read and write capabilities. On GNU/Linux, it uses the libusb, which sadly can’t be used at the same time as the HID input driver. Fortunately, the UHID driver allows to pipe the HID input reports from libusb (userspace) to the HID input driver (kernelspace). One issue that arises when using UHID is that the generic HID input driver applies deadzones to all axes, which is a questionable choice… Anyway, this complicates the setup as this requires to calibrate the wheel. I realized that modifying all the Joystick and Gamepad usages to the Multiaxis Controller usage in the HID report descriptor makes the kernel not to apply undesired deadzones. This removes the need for a calibration step!
When using Logitech wheels in both GNU/Linux and Windows, the pedals axes are translated by the operating system from an absolute range (e.g. [0..255] with 255 the rest value) to a relative range ([-32767..32767] with 32767 the rest value). The existing GIMX axis translation parameters (dead zone, sensitivity, acceleration) do not allow to translate the pedal axes back to an absolute range. To fix this, I added joystick correction parameters to the configuration files, that can be configured in a new “Joystick corrections” panel of the existing “Overall” panel (in gimx-config). The default configuration files for the Momo Racing, the DFGT and the G27 contain these new parameters. These files can be downloaded using the “Help>Download Configs” menu item (in gimx-launcher).
When connecting a Logitech wheel to the Raspberry Pi running Raspbian Jessie, the wheel remains in compatibility mode (making the wheel behave as a Driving Force wheel for example). This makes the default configurations unusable. One work-around to this is to use LTWheelConf to enable the native mode, but it’s not convenient as it has to be done again after each reboot. I decided to automatically enable the native mode in GIMX. When starting GIMX, all Logitech wheel connected to the system are switched to their native modes.