Your system information

• Steam client version: both 2021-07-20T22:25:57 and the 2021-08-11T17:14:33 beta
• Distribution (e.g. Ubuntu): XUbuntu 20.04
• Opted into Steam client beta?: makes no difference
• Have you checked for system updates?: Yes

Please describe your issue in as much detail as possible:

I expected Steam's controller gyro calibration to compensate for slight drift in my DS4 controller. It doesn't.

I tried full autocalibration, gyro-only calibration, with and without auto-calibrate gyro during use, with and without Big Picture Mode, with and without the Steam client beta, with both bluetooth and USB connections. In every case, the calibration sequence completes, but has no effect at all.

Steps for reproducing this issue:

1. Connect or pair a DualShock 4 controller that has a slight gyro drift. (If only a perfectly drift-free controller is available, plan to simulate one with drift by using a non-level surface during calibration.)
2. Enable PlayStation Configuration Support in Steam's controller settings.
3. Complete all the steps in Steam's controller calibration tool, with the controller on a stable reference surface. (A level surface if you're using a controller with drift, or a non-level surface if you're simulating drift with a drift-free controller.)
4. Start Big Picture Mode
5. Launch a game that can respond to (or at least show) mouse input. (Floating Point is a free and easy example. I used Proton 5.0 with the games I tested.)
6. Press the controller's PlayStation button and enter Steam's controller configuration for this game.
7. Configure the gyro as follows:
   Input Style: Joystick Move
   Output: Relative Mouse
8. Return to the game.
9. Watch as the in-game mouse constantly moves, even when the controller is sitting on the reference surface that was used during calibration.