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Steam Deck Controls Do Not Show Up In The Browser Tester In Desktop Mode

Asked by Sebastian H.0 views

I'm in Desktop Mode on my Steam Deck trying to check my sticks with your stick drift test. The page just says press any button, but the buttons move the mouse and type instead. I'm using Firefox from the Discover store. Is the Deck not supported?

Brand
Valve
Model
Steam Deck LCD
Connection
Built-in
System
SteamOS
Browser
Firefox 148
Using Gamepad Tester ToolsSteam Deck
Test used in this questionStick Drift TestDetect unwanted stick movement while you keep your hands off
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Short Answer

In Desktop Mode, Steam maps the Deck's controls to mouse and keyboard, so the browser never sees a gamepad. Add the browser to Steam as a non-Steam game and launch it from Steam, so Steam presents the controls as a gamepad. Steam's own controller test in Game Mode also shows live stick positions.

Verified By Gamepad TesterVerified By Gamepad Tester
Lucas Rocha
Lucas RochaVerified Gamepad Tester team memberGamepad Tester Team
Linux And Input Subsystem Engineer · 12+ years experience · Answered Feb 12, 2026

The Deck is supported, but Desktop Mode hides its controls from the browser by design. In Desktop Mode, Steam runs a desktop configuration that turns the sticks, trackpads and buttons into mouse and keyboard input so you can use the desktop. The browser receives mouse movement and key presses, never a gamepad, which is why the page waits for a button press that never comes.

The reliable fix is to launch the browser through Steam. When a program starts from Steam, Steam Input applies a gamepad configuration instead of the desktop one and presents the Deck's controls as a standard gamepad that browsers can read.

There is a quicker way to answer your actual question too. If all you want is to check the sticks, Steam's controller settings in Game Mode include a test screen with live stick positions. Our browser test adds exact numbers and a drift log, which is handy for tracking a stick over time, but for a quick health check Steam's screen is fine.

One note on readings: the Deck's thumbsticks have capacitive touch sensing, so keep your thumbs fully off them during a drift test for a fair resting value.

Step By Step Fix
  1. In Desktop Mode, open Steam, choose Add a Game, then Add a Non-Steam Game, and select Firefox.
  2. Launch Firefox from your Steam library rather than from the desktop menu.
  3. Open the stick drift test, tap the page and press a button. The Deck should now appear as a gamepad.
  4. If the Flatpak browser still sees nothing, check that it has device access, for example with the Flatseal app.
  5. Set the Deck on a table with thumbs off the sticks and read the resting values for 30 seconds.
  6. For a quick check without the browser, use the controller test screen in Steam's settings in Game Mode.

Tested on: Applies to Steam Deck LCD and OLED in Desktop Mode with Firefox from the Discover store. Behaviour per Valve's Steam Input documentation on configurations.

Sources
  1. Steam Input gamepad emulation best practices
  2. W3C Gamepad API specification

Checked by Simon Fletcher on . How we verify answers

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Community Replies 3

  • Accepted Solution
    Wyatt BishopCommunity Member

    Adding Firefox as a non-Steam game worked first time. The stick test reads the Deck as a gamepad now.

  • Sebastian HoltCommunity Member

    Worked. Left stick 0.01, right 0.00. Also didn't know the Game Mode test screen existed, very handy.

  • Elif YılmazCommunity Member

    Chrome as a Flatpak needed device permission through Flatseal before it saw anything. Firefox was fine for me.

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Lucas Rocha
Written and tested by

Lucas RochaVerified Gamepad Tester team member

Linux And Input Subsystem Engineer at Gamepad Tester

Lucas works on the Linux input subsystem. He follows how evdev registers a controller, how Steam Input sits on top of it and where the two disagree with the browser's view of the same device, which is the usual reason a pad behaves differently on a Steam Deck or a Linux desktop than on Windows. His testing targets parity: the same controller should produce the same reading on every operating system, and where it does not, the difference should be documented. On Gamepad Tester he handles the Linux and Steam Deck questions.

Linux evdev inputSteam InputSteam Deck controller handlingcross-platform input parity
  • 5 answers on Gamepad Tester
  • 12+ years experience
  • Compares controller readings across Linux, Steam Deck and Windows to confirm cross-platform parity.
  • Reviewed by Simon Fletcher
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