Fix: PS4 UDEV Symlink Rule

[luis-camero]

Disable symlink rule to rely on DS4DRV instead.

The clearpath_bt_joy rule is installed with priority 60, which is higher than the ds4drv rules, 50-ds4drv.rules. Therefore, the clearpath_bt_joy rules would symlink the ps4 device to the latest js* device with name Wireless Controller, instead of the DS4DRV Managed Wireless Controller.

The issue with the controller was caused by the clearpath_bt_joy rule mapping the ps4 device to the js1 input. When the controller was disconnected, the ps4 device would map to js0, which would coincidentally allow the joy node to open the right device. When the controller was connected, the ps4 device would switch to js1, but because the joy node had already launched, it would continue to read from js0 and successfully get the commands to the robot. When the joy node was restarted, the ps4 device would be pointing to js1 and now the node would open the incorrect device.

[civerachb-cpr]

Rather than removing the symlink, which will break any robot.yaml files that reference /dev/input/ps4 & invalidate some of our existing documentation, would a better solution be to just change the priority?

e.g. if we remove the symlink at /dev/input/ps4 we also need to update our default teleop configurations, e.g.

• https://github.com/clearpathrobotics/clearpath_common/blob/jazzy/clearpath_control/config/a300/teleop_ps4.yaml#L74
• https://github.com/clearpathrobotics/clearpath_common/blob/jazzy/clearpath_control/config/r100/teleop_ps4.yaml#L77
• etc...: this will affect every supported platform

[civerachb-cpr]

See comment above: we can't just arbitrarily remove the symlink if we don't also update the default PS4 teleop configurations.

Is simply changing the priority of the udev rule in our package an option instead of removing the symlink?

[tonybaltovski]

The symlink happens in the ds4drv package. It will continue to exist and provide /dev/input/ps4. Therefore, it will not break anything correct? This package is not used at the moment and was supposed to replace ds4drv but that isn't the case currently.

[civerachb-cpr]

The symlink happens in the ds4drv package. It will continue to exist and provide /dev/input/ps4. Therefore, it will not break anything correct? This package is not used at the moment and was supposed to replace ds4drv but that isn't the case currently.

My mistake! I thought the ds4drv package was providing /dev/input/ds4 (or something similar). If it's already providing an identical symlink then there's not much need to override it with our own rule.