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fix(vdisplay): the wlr-family backends asserted a cursor mode instead of negotiating it, so the portal refused the call
Hyprland and wlroots both hardcoded portal `CursorMode::Metadata` whenever the
session had negotiated the cursor channel, and never asked the backend what it
supports. That is not a soft failure: xdg-desktop-portal's FRONTEND validates the
requested mode against the backend's `AvailableCursorModes` and fails the call
with `"Unavailable cursor mode %x"` before the backend ever sees it.

So a cursor-forward session (desktop mouse mode) died at `select_sources`,
surfacing as "pipeline build failed" and a black client, with
`unavailable cursor mode 4` in the portal log. Field report 2026-08-14.

MEASURED on .21 the same day, and it is worse than the report suggested: against
a LIVE Hyprland 0.56.2 with xdg-desktop-portal-hyprland 1.4.1 and
xdg-desktop-portal 1.22.1 — all current — `AvailableCursorModes` reads **3**
(Hidden|Embedded) on both the backend impl interface and the frontend. xdph does
not offer the metadata cursor at all, so this broke EVERY cursor-forward session
on current Hyprland, not merely on old installs. Updating the portal would not
have helped. xdpw is the same from the other end: its screencast.c refuses
METADATA outright.

pf-capture's own portal path has always negotiated (`choose_cursor_mode`); this
restates that ladder in pf-vdisplay, which may not depend on pf-capture. The
downgrade is graceful rather than merely survivable: with the portal on Embedded
no `SPA_META_Cursor` arrives, so the host feeds the cursor channel nothing and a
cursor-forward client draws nothing of its own — one pointer, not two.

`PUNKTFUNK_PORTAL_CURSOR_MODE=auto|hidden|embedded|metadata` pins the preference
for a backend that advertises a mode it implements badly, which negotiation
cannot detect. It is a preference only: pins run the same ladder, so no value can
re-create the refused request.

The module is declared unconditionally so its ladder tests run on every CI leg
rather than only the one that compiles `mod hyprland` — including a Linux-only
test pinning our bit values against ashpd's enum, verified non-vacuous by
planting a wrong discriminant (ashpd answers 4 for Metadata, the number in the
report). The regression test uses 3, the bitfield measured on glass. Linux: 225
tests pass, clippy --all-targets -D warnings clean.
2026-08-14 10:27:14 +02:00

7.0 KiB
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title, description
title description
Hyprland Configure a Punktfunk host on a Hyprland session — headless output via hyprctl, capture via xdg-desktop-portal-hyprland.

Hyprland is a first-class backend. The host adds a per-client headless output at the client's exact mode with hyprctl, captures it through the xdg-desktop-portal-hyprland (xdph) ScreenCast portal (zero-copy dmabuf), and injects input via the wlroots virtual pointer/keyboard protocols — which Hyprland still implements even after dropping wlroots in v0.42.

This is a distinct backend from Sway / wlroots: Hyprland has its own IPC (hyprctl) and its own portal (xdph), so it is auto-detected and driven separately.

This page assumes the package is already installed — see Arch, Ubuntu, or Fedora.

New here? Read Security & Safe Use first — a streaming host is remote control of the machine, so keep it on a trusted LAN or VPN and require pairing.

host.env

The host auto-detects a Hyprland session, so the starter ~/.config/punktfunk/host.env is one line:

PUNKTFUNK_VIDEO_SOURCE=virtual
# GPU zero-copy capture→encode is ON by default; auto-falls back to CPU. Set PUNKTFUNK_ZEROCOPY=0 to force CPU.

To force the backend (CI/testing — note that pinning turns live-session auto-detection off, so the host stops following session switches):

PUNKTFUNK_COMPOSITOR=hyprland
PUNKTFUNK_INPUT_BACKEND=wlr

See Configuration for the full reference.

How it works

  • Video — the host runs hyprctl output create headless PF-1 and applies a monitor rule for the client's exact mode. Outputs are named, so there's no before/after diffing. The rule uses hyprctl keyword monitor … (the hyprlang config manager — the default on every release, 0.55 included) and falls back to the Lua hyprctl eval 'hl.monitor{…}' only if you've opted into the Lua config manager. The host confirms the output actually adopted the mode before streaming.
  • Capture — it captures that output through the xdg-desktop-portal-hyprland (xdph) ScreenCast portal. To pick the output without a GUI on a headless host, the host writes a managed ~/.config/hypr/xdph.conf pointing xdph's custom_picker_binary at a small shim that selects the new output automatically — no interactive picker dialog to answer.
  • Input — mouse and keyboard are injected via the wlroots virtual pointer and virtual keyboard protocols (Hyprland kept them). Gamepads and audio are compositor-independent.

For how long the virtual output lives, and extend-vs-exclusive topology, see Virtual displays.

Requirements

  • A running Hyprland session (the hyprctl/xdph contracts are verified on 0.55.4; older releases share the same hyprctl surface).

  • xdg-desktop-portal-hyprland (xdph) installed and running — the host captures through its ScreenCast portal, and steers its custom picker. Without it there is no video.

  • ScreenCast routed to xdph — only if another portal backend (gtk, wlr) is installed alongside it. xdg-desktop-portal picks one implementation per interface, and if it hands ScreenCast to the wrong backend the host steers an xdph picker nobody is reading. Pin it for your session by creating ~/.config/xdg-desktop-portal/hyprland-portals.conf (the name is your session's desktop — XDG_CURRENT_DESKTOP, which is Hyprland here — lowercased):

    [preferred]
    default=gtk
    org.freedesktop.impl.portal.ScreenCast=hyprland
    

    Then systemctl --user restart xdg-desktop-portal. On a box with only xdph installed there is nothing to choose between, so you can skip this.

Troubleshooting: black / no video (headless output at 0×0)

A headless output only gets a framebuffer once the compositor can allocate one. On some GPU/driver combinations (notably NVIDIA, and in nested test setups) that GBM/dmabuf allocation fails and the output stays 0×0 — you'll see GBM: Failed to allocate a GBM buffer: bo null in the Hyprland log (cf. Sunshine #4197). The host detects this and fails the session with a clear error rather than streaming a blank surface. If you hit it, capture the Hyprland log (hyprctl instance dir → hyprland.log) and check your GPU's GBM support; running Hyprland as a real session (not nested) is the supported configuration.

Troubleshooting: black client + "unavailable cursor mode 4"

A black client, pipeline build failed in the host log, and unavailable cursor mode 4 from xdph are one failure, not three.

4 is the ScreenCast portal's metadata cursor mode, which the host prefers when the client draws the pointer locally (desktop mouse mode). xdg-desktop-portal-hyprland does not offer that mode — on a current stack (Hyprland 0.56.2, xdph 1.4.1) its AvailableCursorModes is 3, meaning hidden and embedded only. Asking for a mode the backend does not advertise is not a soft failure: xdg-desktop-portal rejects the call outright, so the cast died during setup and the client had nothing to show.

Updating xdph does not fix this — the mode is absent on current versions, not just old ones. Hosts from this release check what your portal advertises and use an embedded cursor instead, so the session streams. If you are on an older host, switch the client to game mouse mode: that stops it asking for the metadata cursor at all.

If the pointer misbehaves on an xdph that does advertise metadata support, pin the mode:

PUNKTFUNK_PORTAL_CURSOR_MODE=embedded

See Configuration.

Permission system

Hyprland's permission system (ecosystem.enforce_permissions, 0.49+, off by default) can deny direct screencopy and virtual-input clients — and denial is silent: capture goes to black frames and input is dropped, with no error. If you've enabled it, grant the host explicitly in your Hyprland config:

ecosystem {
    enforce_permissions = true
}

permission = /usr/bin/punktfunk-host, screencopy, allow
permission = /usr/bin/punktfunk-host, virtual-pointer, allow
permission = /usr/bin/punktfunk-host, virtual-keyboard, allow

The host logs a warning at startup when it detects enforcement is on. (Adjust the binary path to where your package installed punktfunk-host.)

Start the host

With the backend selected, start the host from inside your Hyprland session:

systemctl --user enable --now punktfunk-host
journalctl --user -u punktfunk-host -f

This unit runs serve --gamestream, so it serves stock Moonlight clients as well as the native ones. For a native-only host, see What the unit starts.

Bring up the console and pair

Enable the web console, read its login password, and arm PIN pairing — see The Web Console. Then connect a client.