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Kabuki94Kabuki94
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WSLg: cairo+software is the default; persistent flatpak overrides
Operator-confirmed across multiple test sessions 2026-05-10: every hardware rendering path on current WSLg + Mesa 25 + GTK 4.16+ ends in one of: (a) GLib G_IS_OBJECT assertion crashes shortly after window spawn (b) "Could not initialize EGL display" + WebKit web-process respawn loops every 200ms (c) Windows registering with weston RDP rail but never displaying content on the Windows host (msrdc-hosted but blank) Cairo + LIBGL_ALWAYS_SOFTWARE=1 + llvmpipe is the only combo that reliably produces stable, non-crashing GTK4 apps on WSLg today. Slow but correct. Operators with a known-stable hardware path opt back in via MIOS_GPU_HARDWARE=1. Two coupled changes: 1. /etc/profile.d/mios-wslg-gpu.sh: invert the toggle. Previous logic was MIOS_GPU_SOFTWARE=1 to OPT INTO software (with hw default). Operator feedback: "the windows never render though" even with hw path verified, multiple sessions. Flip the polarity so software is the safe default; MIOS_GPU_HARDWARE=1 is the opt-in for when upstream stabilizes. 2. /var/lib/flatpak/overrides/<app> (NEW): six system-level flatpak overrides pinning GSK_RENDERER=cairo + LIBGL_ALWAYS_SOFTWARE=1 inside each flatpak sandbox (sandboxes don't inherit profile.d). Apps covered: org.gnome.Epiphany, org.gnome.Nautilus, org.gnome.Software, com.github.tchx84.Flatseal, com.mattjakeman.ExtensionManager, com.vscodium.codium. Verified live: with override applied, Epiphany flatpak survives spawn (5 processes alive 15s in, no EGL/MESA/Vulkan errors, weston window registered). Without override, same flatpak hits "Failed to realize renderer 'GskGLRenderer'" + tight web-process crash loop. System-level overrides (here at /var/lib/flatpak/overrides/) apply to all users. User-level (~/.local/share/flatpak/overrides/) would only affect mios. The system-level placement plus repo tracking means the override survives flatpak --reset, reinstall, user deletion, and re-bootstrap. .gitignore: allowlist entries for /var/lib/flatpak/overrides/*. Known gap NOT solved by this commit: WSLg's host-side bridge issue where windows register with WSLg's RDP rail but msrdc doesn't actually display the surface content. This appears distinct from the Mesa/Vulkan render path (xeyes -- pure XLib, zero GPU -- has the same symptom in some sessions). Operator visibility hits both upstream WSLg and Microsoft RDP-RAIL host behavior, neither of which MiOS controls. Further mitigation may require switching to Sunshine + Moonlight streaming, X410, or waiting for WSLg fixes.
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‎.gitignore‎

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@@ -482,6 +482,13 @@ var/*
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var/lib/*
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!/var/lib/mios/
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!/var/lib/mios/**
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# /var/lib/flatpak/overrides/ -- per-app environment overrides that
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# get applied INSIDE the flatpak sandbox. Tracked here so software-
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# rendering defaults survive operator deletions + re-install.
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!/var/lib/flatpak/
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!/var/lib/flatpak/overrides/
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!/var/lib/flatpak/overrides/*
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# Cookbooks (was /usr/local/share/mios/cookbooks/), prompt templates
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# (was /opt/mios/prompts/), and API examples (was /srv/mios/api/) all
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# moved to /usr/share/mios/{cookbooks,prompts,api}/ as of v0.2.3 path-

‎etc/profile.d/mios-wslg-gpu.sh‎

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[ -d /mnt/wslg ] || return 0
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# ── Cairo / software-rendering fallback toggle ───────────────────
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# Set MIOS_GPU_SOFTWARE=1 to force CPU-only rendering (cairo +
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# llvmpipe). Slow but always produces visible content -- useful
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# when dzn / d3d12 / NVIDIA paths are all failing for a specific
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# app. Operator can flip per-shell or persist via
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# ~/.config/environment.d/. Default (unset) = hardware-accelerated
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# d3d12 path below.
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if [ "${MIOS_GPU_SOFTWARE:-0}" = "1" ]; then
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export GALLIUM_DRIVER="${GALLIUM_DRIVER:-llvmpipe}"
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export LIBGL_ALWAYS_SOFTWARE=1
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# ── Mesa / GTK4: cairo + llvmpipe is the WSLg default ────────────
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# Operator-tested across multiple sessions 2026-05-10: every
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# hardware path (dzn Vulkan, d3d12 Gallium, NGL, GL renderer)
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# resulted in either:
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# (a) Apps spawning windows then crashing on GLib G_IS_OBJECT
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# assertions or "Could not initialize EGL display"
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# (b) WebKit "Web process crashed" in tight respawn loops
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# (c) Windows registering with weston RDP rail but never
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# displaying content on the Windows host
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# Cairo + LIBGL_ALWAYS_SOFTWARE=1 + llvmpipe is the only combo
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# that reliably produces stable, non-crashing GTK4 apps on WSLg
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# with current Mesa 25 / dzn / GTK 4.16+ versions. Slow but
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# correct. Per-flatpak overrides at /var/lib/flatpak/overrides/
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# pin the same env inside flatpak sandboxes (which don't inherit
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# this profile.d).
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#
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# When upstream WSLg + Mesa stabilize, flip MIOS_GPU_HARDWARE=1
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# to opt back into the hardware path. Empty / unset = software.
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if [ "${MIOS_GPU_HARDWARE:-0}" = "1" ]; then
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# Hardware-accelerated path: skip the software defaults and
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# let GTK4 / Mesa pick their own. Operator ack of expected
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# instability on current WSLg versions.
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export LIBGL_KOPPER_DISABLE="${LIBGL_KOPPER_DISABLE:-1}"
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else
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# Software path -- the default.
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export GSK_RENDERER="${GSK_RENDERER:-cairo}"
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return 0 2>/dev/null || exit 0
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export LIBGL_ALWAYS_SOFTWARE="${LIBGL_ALWAYS_SOFTWARE:-1}"
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export GALLIUM_DRIVER="${GALLIUM_DRIVER:-llvmpipe}"
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export LIBGL_KOPPER_DISABLE="${LIBGL_KOPPER_DISABLE:-1}"
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fi
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# ── Mesa / GL ────────────────────────────────────────────────────
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# Mesa-25+ replaced the old DRI2 path with Kopper for X-on-Vulkan;
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# Kopper on WSLg goes through Zink which goes through dzn (broken
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# for many GTK4 features) -- disable Kopper unconditionally to
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# keep apps off the Zink path. This alone is non-destructive.
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export LIBGL_KOPPER_DISABLE="${LIBGL_KOPPER_DISABLE:-1}"
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# d3d12 Gallium driver targets WSLg's WDDM via /dev/dxg.
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# Operator-tested 2026-05-10: forcing GALLIUM_DRIVER=d3d12 +
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# GSK_RENDERER=gl made GTK4 apps spawn windows but they crashed
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# shortly after on GLib G_IS_OBJECT assertions (Zink / dzn
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# inconsistency in the GTK4 GL renderer's surface handling).
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# Defaulting to MESA's auto-detection has proved more stable --
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# the loader picks llvmpipe (CPU) when no real GPU surfaces, and
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# GTK4's NGL renderer falls back to its own GL implementation.
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# Operators on hosts where d3d12 IS reliable can opt back in:
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# export GALLIUM_DRIVER=d3d12
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# export MESA_LOADER_DRIVER_OVERRIDE=d3d12
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# export GSK_RENDERER=gl
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# ── GTK4 / GSK ───────────────────────────────────────────────────
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# Don't force GSK_RENDERER -- let GTK4 auto-detect. On WSLg with
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# Mesa 25 the auto path picks NGL which works for most apps.
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# When NGL fails (operator sees app-crash-shortly-after-spawn),
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# flip to MIOS_GPU_SOFTWARE=1 (block above) for cairo + llvmpipe.
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# ── WebKit (Epiphany / GNOME-Web) ───────────────────────────────
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# WebKit-on-WSLg works best with hardware compositing disabled --
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# the dzn path can't reliably back WebKit's compositing layers.

‎var/lib/flatpak/overrides/com.github.tchx84.Flatseal‎

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[Environment]
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GSK_RENDERER=cairo
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LIBGL_ALWAYS_SOFTWARE=1
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GALLIUM_DRIVER=llvmpipe
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LIBGL_KOPPER_DISABLE=1
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WEBKIT_DISABLE_COMPOSITING_MODE=1

‎var/lib/flatpak/overrides/com.mattjakeman.ExtensionManager‎

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[Environment]
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GSK_RENDERER=cairo
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LIBGL_ALWAYS_SOFTWARE=1
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GALLIUM_DRIVER=llvmpipe
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LIBGL_KOPPER_DISABLE=1
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WEBKIT_DISABLE_COMPOSITING_MODE=1

‎var/lib/flatpak/overrides/com.vscodium.codium‎

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[Environment]
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GSK_RENDERER=cairo
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LIBGL_ALWAYS_SOFTWARE=1
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GALLIUM_DRIVER=llvmpipe
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LIBGL_KOPPER_DISABLE=1
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WEBKIT_DISABLE_COMPOSITING_MODE=1

‎var/lib/flatpak/overrides/org.gnome.Epiphany‎

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[Environment]
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GSK_RENDERER=cairo
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LIBGL_ALWAYS_SOFTWARE=1
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GALLIUM_DRIVER=llvmpipe
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LIBGL_KOPPER_DISABLE=1
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WEBKIT_DISABLE_COMPOSITING_MODE=1

‎var/lib/flatpak/overrides/org.gnome.Nautilus‎

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[Environment]
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GSK_RENDERER=cairo
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LIBGL_ALWAYS_SOFTWARE=1
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GALLIUM_DRIVER=llvmpipe
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LIBGL_KOPPER_DISABLE=1
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WEBKIT_DISABLE_COMPOSITING_MODE=1

‎var/lib/flatpak/overrides/org.gnome.Software‎

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[Environment]
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GSK_RENDERER=cairo
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LIBGL_ALWAYS_SOFTWARE=1
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GALLIUM_DRIVER=llvmpipe
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LIBGL_KOPPER_DISABLE=1
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WEBKIT_DISABLE_COMPOSITING_MODE=1

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