Configuration Outputs

Displays

Color temperature

Night light warms the display using its hardware gamma ramp. It is off by default. Set its state and temperature in config.kdl:

night-light {
    enabled #false
    temperature 4500
}

The temperature range is 1000–6500 K. Lower values are warmer. At 6500 K, the display keeps its neutral color. The panel's Night light item opens an on/off switch and temperature slider. In Morph, the button stays beside the tabs when you expand the panel, even if you remove the Night light item from your panel layout. Quick Settings has the same controls. The toggle saves immediately. Releasing the slider saves its temperature in the config.

Night light applies to all supported connected displays, including mirror targets. It requires a DRM session. A nested session cannot change the host display's colors. There is no automatic schedule yet.

External gamma-control clients

Ferese supports wlr-gamma-control-unstable-v1 on DRM outputs with hardware gamma ramps. A gamma-control client can adjust the display's color temperature. Only one client can control each output at a time. While that client remains connected, Ferese reapplies its gamma table after display sleep or a session switch. Closing the client restores the previous table.

Nested outputs and hardware without gamma-ramp support report that gamma control is unavailable. This protocol does not provide ICC profiles or HDR color management.

When you turn on night light, Ferese takes control of the gamma tables and sends external controllers failed. These clients must request gamma control again after you turn it off. New requests are rejected while night light is on.

Output profiles

Each output-profile needs a unique, nonempty name and at least one output entry. A profile matches when every required monitor is connected and its optional lid-closed condition matches. The profile with the most required monitors wins; ties use config order. If none matches, Ferese extends across all usable connected monitors. Find selectors with feresectl outputs.

output-profile key	Type	Default
name	unique nonempty string	required
layout	internal-only, external-only, extend, mirror	extend
lid-closed	boolean	either lid state
mirror-source	selector of an enabled output in this profile	first enabled hardware key
lid-policy	dock-or-suspend, ignore	dock-or-suspend
confirm-timeout	seconds; 0 disables confirmation	15

output-profile → output key	Type	Default
match	nonempty connector or persistent identity string	required; unique within profile
required	boolean	true; set false for an optional monitor
enabled	boolean	true
mode	"WIDTHxHEIGHT" or "WIDTHxHEIGHT@HZ"	Preferred mode
auto-refresh	boolean	false
adaptive-sync	boolean; requires connector and atomic KMS support	false
allow-tearing	boolean; permits supported clients to request asynchronous flips	false
scale	number > 0	1
transform	enum below	"normal"
position	[integer, integer]	Automatic horizontal placement

Transforms: normal, rotate-90, rotate-180, rotate-270, flipped, flipped-90, flipped-180, flipped-270. In extend and mirror profiles, unlisted monitors stay enabled with defaults. Internal-only and external-only filter by connector type. A layout that would disable the final usable display falls back to a working display. Profiles that explicitly disable all their listed outputs are invalid.

adaptive-sync=#true explicitly enables variable refresh on a supported output. The request is validated and restored with the rest of the output transaction. Mirror sources and targets reject adaptive sync because their presentation clocks are coupled. IPC exposes support, requested state, and applied state separately; an unsupported request fails without silently enabling a different policy.

allow-tearing=#true permits asynchronous flips when the atomic DRM driver advertises support and a fullscreen client commits an asynchronous presentation hint. Ferese requires a settled, unlocked fullscreen surface using primary direct scanout. Mirroring, pending capture, variable refresh, and FIFO-constrained updates keep synchronized presentation. Unsupported asynchronous driver requests retry ordinary presentation. IPC reports tearing_supported and allow_tearing; permission alone does not imply every frame tears.

required controls whether a profile matches when a monitor is absent. Every connected monitor enabled by the resolved policy, including optional monitors and mirror targets, needs its own compatible CRTC assignment. Ferese rejects an incomplete assignment before applying the configuration. A complete assignment still needs to pass driver validation; connector compatibility alone does not establish that the hardware accepts the modes and planes.

Monitor identities use EDID manufacturer, product/model and serial, rather than a hash of the entire EDID. Without a usable serial, the identity includes the GPU's sysfs hardware path and connector. For duplicate serials, Ferese adds the same path and connector to distinguish the monitors. If both arrive together, both identities include those details. If the second arrives later, the first keeps its identity and only the second gets the path and connector. Ferese remembers that choice for the compositor session. Without serials, Ferese identifies monitors by port and cannot tell them apart if you swap their ports. Connector names and old drm-edid: selectors still work. Ambiguous or overlapping selectors are rejected during live reload. A disconnected identity can remain in config; it prevents matching only when its entry has required=#true.

output-profile "desk" layout="external-only" {
    output "DP-1" mode="2560x1440@60" scale=1.25
    output "eDP-1" required=#false enabled=#false
}

output-profile "mobile" layout="internal-only" {
    output "eDP-1" scale=1.75
}

output-profile "presentation" layout="mirror" mirror-source="eDP-1" {
    output "eDP-1" scale=1.75
    output "HDMI-A-1" mode="1920x1080@60"
}

Mirror uses the source's logical size, workspace, layers and pointer. Targets own no workspaces or separate pointer region. Ferese fits the complete source into each target's transformed physical mode, preserving aspect ratio and letterboxing instead of cropping. Target scale does not resize the source layout. Each target has its own hardware cadence; only the source releases client frame callbacks and presentation feedback. Mirrored monitors are listed by outputs, but expose one logical output to clients and the shell. If a required mirror target disconnects, Ferese selects another matching profile or extends across all usable connected monitors. Leaving mirror restores evacuated workspaces.

feresectl outputs
feresectl output-profiles
feresectl toggle-display-mode
feresectl output-layout extend
feresectl output-profile presentation
feresectl output-confirm
feresectl output-profile auto
feresectl output-internal off
feresectl output-revert

The display Fn key (XF86Display) and the bar’s display icon open the same display-mode chooser. The icon appears while an external monitor is connected. output-layout selects a layout without requiring a named profile and keeps the matching profile’s mode, scale and transform settings.

A manual choice overrides automatic selection until the monitor set or lid state changes. Reload keeps it only if its profile still exists and matches. Manual changes revert after confirm-timeout seconds unless confirmed; output-revert restores immediately. Reverting restores the last confirmed modes, scales, transforms and positions, even if you make several changes before confirming. The timeout still applies if the client that made the change exits. Automatic hotplug/lid changes never wait for confirmation. Disabling the last usable internal panel is rejected.

output-profile name="docked" {
    output match="HDMI-A-1" scale=1.5 {
        position 0 0
    }
}

Settings → Displays offers the connected display's supported refresh rates at its configured resolution. Choosing a rate saves it and disables Auto. Choosing Auto saves the highest supported rate as the normal mode and enables automatic switching. These choices apply immediately for the active profile and persist across restarts.

With auto-refresh=#true, a discharging system battery below 30% switches the display to a supported mode within 1 Hz of 60 Hz at the same resolution. The configured normal mode returns on external power or when the battery reaches 35%. Power is checked every five seconds; mode changes only run when the policy changes. Unavailable battery data restores normal refresh. If no matching 60 Hz mode exists, normal refresh is retained. Rejected DRM mode changes retain the current output. A refresh-rate change can briefly blank the display (about one second on some panels), including automatic changes below 30%, recovery at 35%, and restoration on AC. Session activation refreshes lid and connector state before rendering; unchanged outputs retain their handles and workspaces. Hotplug bursts settle for 150 ms before one reconciliation. Ferese records changes that arrive while the session is inactive and applies them on activation.

output-profile laptop {
    output eDP-1 mode="2880x1800@120" scale=1.75 auto-refresh=#true
}

With a usable external display, closing the lid disables internal panels after external activation succeeds. Without one, Ferese asks logind to suspend, respecting sleep inhibitors. lid-policy="ignore" disables this behavior for the selected profile. Resume reads lid state from logind, with ACPI fallback, before reconciling fresh hardware. Ferese releases its logind lid inhibitor on session pause, so logind handles the lid while another session or TTY is active. Workspaces keep their home output and return when it reconnects, unless you reassigned or deleted them after evacuation. Floating windows are remapped and clamped to the surviving display.

On atomic DRM, Ferese tests the complete configuration for each GPU before changing it. Smithay performs the real commits; logical changes follow successful hardware application. Failed commits attempt restoration, and outputs that cannot be restored are removed from logical state. Each GPU commits separately. If a later GPU fails, Ferese attempts to restore the earlier GPUs. Legacy KMS lacks atomic test-only validation. Hardware failures can still leave the session without a working monitor; Ferese tries preferred modes to recover a display instead of intentionally turning off the last working one.