# Display Control

Studio only shows Display Control actions that the Player reports as available. Support depends on the Linux host, adapter, cable path, display, and firmware.

## Check the stable Linux Player

The current Electron Linux Player uses HDMI-CEC for supported power and input controls, and DDC/CI for supported brightness and volume controls.

Check:

- the CEC adapter or `/dev/cec*` device exists for CEC controls;
- the Player account can access the CEC device;
- the display's I²C/DDC path is visible for DDC/CI;
- `cec-ctl` and `ddcutil` are installed for the stable Player;
- the display actually supports the DDC/CI control you are trying to use.

A missing control should not interrupt normal signage playback.

## Sent does not always mean confirmed

A successful Tilecast request can mean the command was sent. It does not always mean the physical display changed state.

If the Player can read the new state back, Studio can confirm more. Otherwise, test the exact adapter, cable path, display model, and firmware before depending on Display Control unattended.

## Tilecast Edge works differently

The Edge M9 preview talks to Linux CEC and I²C/DDC devices directly instead of using the stable Player's command-line providers.

Do not remove `cec-ctl` or `ddcutil` from a stable Linux Player because of the Edge preview.

See [Display Control](../../screens/display-control/) and [Edge hardware integrations](../../edge/hardware/) for the two Linux Player paths.