Per "Fixed a library compatibility issue that resulted in gamepad support not working" in the 2018-05-18 Steam beta client update, please opt into Steam's beta client and check if the behavior has improved.
Have the same gamepad, seems to work for navigation and gameplay but doesn't get detected in controller settings as ashleybone has reported.
This issue is fixed for me as of the 2018-05-18 client update (release update, not beta).
Closing as fixed in the 2018-05-18 Steam stable client update.
Nothing extracted yet.
Your system information
Please describe your issue in as much detail as possible:
I have a Logitech F310 gamepad which has worked with Steam on Linux for several years. After installing the May 16 2018 Steam update, the gamepad is no longer detected. When I open Controller Settings, it displays the message "No Controllers Detected".
When I launch Hollow Knight from Steam, it does detect the gamepad, and plays normally. However, Iconoclasts doesn't see the gamepad at all. Prior to this Steam update, Iconoclasts worked normally with my gamepad.
Steps for reproducing this issue: