punktfunk/docs/releases/v0.20.1.md

Update whenever it suits you — the app and the machine you stream from can still be updated one at a time, and everything already paired keeps working. This release is entirely fixes and hardening on top of last release's session⇄game work — nothing new to opt into.

## Fixed: installing or updating the Windows host

Three separate reports came in within hours of the last release, all blocking install:

- **`winget install` could fail outright if you'd ever had another streaming host on the machine** — even one you had since disabled or mostly uninstalled. A leftover, disabled service or an empty folder from an old install was enough to trip the "conflicting host" check and abort. Only a host actually set to start on its own counts now.
- **Installing through a package-manager app (like UniGetUI) could fail with a file-path error** before the install wizard ever appeared, because of a broken setting the installer passed itself. Fixed.
- **The package source instructions were incomplete.** `winget install unom.PunktfunkHost` says "no package found" until you've pointed winget at Punktfunk's own source, once per machine — the command for that is now spelled out.

## Fixed: Moonlight compatibility no longer turns on without asking

A fresh Windows install used to enable Moonlight-app compatibility silently, with no checkbox ever shown — even though that mode pairs over a less secure connection and the host warns about it on every start. It's opt-in now. Existing installs are untouched either way; Punktfunk's own clients were never affected.

## Fixed: switching into Steam's Game Mode on Linux could black out the machine

Last release shipped the permission needed to properly take over the screen for Steam's Game Mode — and surfaced a few sharp edges that only show up once that takeover is actually live:

- **The takeover could kill Punktfunk's own background service a few seconds later**, leaving the display dark with nothing left to bring it back except a physical console or SSH.
- **It could also hang waiting on a permission prompt nobody could see**, delaying recovery until well after the stream had already dropped — or act on a leftover marker file from months ago and jump the machine to the desktop for no reason.
- **Restarting the host mid-stream** — including a routine update — **could leave the display stuck off**, since nothing told the screen to come back.

All three are fixed. Recognizing the machine's built-in Steam Game Mode may now need a one-time permission on some distributions; installing or updating normally takes care of it.

## Fixed: a laptop with its built-in screen turned off stuttered constantly

On a laptop with two graphics chips and the internal screen switched off — a common setup for streaming from a laptop docked to a TV or monitor — streaming stuttered roughly every two seconds, for the whole session. Punktfunk now recognizes a dark-but-connected laptop screen as the cause and points at the actual fix, instead of pointing at an external monitor that isn't the problem.

## Fixed: latency creeping up over the course of a fast, high-bitrate stream

On a fast local network, especially at higher bitrates, latency could climb steadily over a long session instead of staying flat. Several separate causes are fixed at once: the stream's internal clock sync could get starved by a busy connection and let the two ends' clocks drift; a stream mode could put more data on the wire than its bitrate setting actually allowed; a slow-to-decode moment could build up a backlog that took a while to work through instead of catching up immediately; and the one-time startup speed test could be mistaken for real network congestion and permanently cap the stream below what the connection could actually handle.

## Fixed: missing cover art looked broken

A library entry with no cover art showed as an empty grey box, which read as something that failed to load. It now shows a controller icon instead, so "no art yet" looks intentional rather than broken.

## Improved: the Windows app now keeps its own log file

The desktop app writes its own log to `%LOCALAPPDATA%\punktfunk\logs\client.log` now, instead of only printing to a console window that a normal launch never shows. If you're ever asked to send logs for a problem, this is where they are.

## Under the hood (for developers)

- **Nothing changed on the wire or at the API boundary.** Streaming protocol stays at version **2**, the embeddable C ABI at **13**, the Windows virtual-display driver protocol at **6** — 0.18–0.20 hosts and clients keep mixing freely.
- **Windows conflict detection** now keys on the competing service's `Start` registry value (0–2 = boot/system/auto only), matching the tray's own dormant-is-harmless logic from last release; install directories no longer count.
- **The winget `Log` switch used the literal string `|LOGPATH|`** instead of winget's actual `<LOGPATH>` substitution token, so Inno received an illegal filename on any install that requested a log (UniGetUI does by default). Guarded by a new manifest check.
- **`gamestream` installer task lost its default-checked flag**; a silent/unattended install now lands `PUNKTFUNK_HOST_CMD=serve`. `/MERGETASKS=gamestream` opts in. Fresh installs only — `GamestreamParam` already omitted the flag on upgrades.
- **The gamescope display-manager takeover** now calls privileged `systemctl` verbs non-interactively (`--no-ask-password`) so a headless polkit prompt can no longer block the stream's own recovery thread; `session_select_requested`'s sentinel baseline is now recorded at takeover time as well as at successful launch, closing a window where a months-old `~/.config/steamos-session-select` write could false-positive a session-select honor; and `punktfunk-host` now handles SIGTERM/SIGINT by restoring the display manager it stopped (20 s grace) before exiting, so a `systemctl --user restart` or package upgrade mid-takeover can't strand the box. The takeover also now ensures the invoking user has systemd lingering enabled before touching the display manager — without it, stopping the DM stops the user's own service manager ~10 s later and takes the host down with it.
- **A new `internal_panel` target class** lets the exclusive-topology stall detector name a deactivated eDP/LVDS laptop panel as a disturbance suspect; previously the suspect list was filtered to external physicals only, so the one display responsible on a hybrid laptop reported as none. `EvtIddCxMonitorI2CTransmit/Receive` now answer every DDC/CI probe against the virtual monitor with an immediate `STATUS_NOT_SUPPORTED`, so third-party brightness/monitor tools stop occupying win32k's serialized physical-monitor path on it. The swap-chain drain thread now falls back to `TIME_CRITICAL` priority if MMCSS registration is refused, and raises `IddMinimumVersionRequired` 4 → 10 to use `IddCxSetRealtimeGPUPriority`.
- **Clock re-sync** now spaces its probe rounds ~7 ms apart, tracks a running best-RTT guard band instead of a static connect-time floor, and applies the best batch of a rejection streak after three consecutive rejections rather than drifting unbounded.
- **A new per-frame `WireBudget`** (shared between encoder backends) tracks the real bitstream-to-wire inflation ratio for datagram-aligned PyroWave sessions and deflates the rate-control target by it, so the configured bitrate pin holds on the wire rather than on the raw codec bitstream.
- **The pre-decode frame channel now drains to the newest AU for all-intra (PyroWave) streams**, since those have no reference chain forbidding a mid-stream drop — capping any standing backlog at roughly one frame instead of ratcheting between the coarse jump-to-live thresholds.
- **The ABR capacity probe's first post-probe report window is now discarded outright**, rather than measured, so the probe's own deliberate overload can no longer read as session congestion and permanently end slow-start early.
- New `display-disturb` dev tool for reproducing DDC/CI and modeset-class display disturbances on demand during stall-immunity testing; not shipped to end users.