Firefox

firefox.*, module firefox. Options: README, Options.

Problem

In the Steam session gamescope never shows fullscreen windows, so Firefox looks frozen when a page goes fullscreen; sites send AV1, which the Frame decodes in software; the two sessions can't see each other's Firefox, so a second instance stops at the locked profile; and without a default browser the portal opens links with the first installed https handler (e.g. Chromium), in both sessions.

What you get

A launcher for the Flathub Firefox Flatpak (org.mozilla.firefox, stable; install it yourself): the Flatpak's own entry with a wrapper in front, same ID, so default-browser associations keep working.

vrFullscreenFix (on): full-screen-api.ignore-widgets makes fullscreen fill just the window. Not applied in the desktop profile.
disableAv1 (off): media.av1.enabled = false. The Frame's decoder driver (iris) has no AV1, only H.264, HEVC and VP9, so YouTube and co. send VP9/H.264, decoded in hardware, instead of software AV1.
prefs: further about:config values for every profile; they can also override the fixes above.
desktopProfile ("desktop"): in the nested desktop the launcher (not its "Open Profile Manager" action) uses this separate profile, a normal Firefox profile with its own browser data, created on first use. null: the default profile in both sessions.
defaultBrowser (off): the launcher becomes the default for http, https and text/html (the launcher's defaultFor: Home Manager's xdg.mimeApps, which then owns ~/.config/mimeapps.list).

prefs and the fixes are default values, not user values: about:config can still change them per profile, and removing one leaves nothing behind. Changes take effect at the next start of Firefox.

Configuration

steamFrame.firefox = {
  enable = true;
  disableAv1 = true;
  defaultBrowser = true;
  prefs."browser.startup.page" = 3;   # restore the previous session
};

Caveats

A user.js of your own in the desktop profile is never touched (the fullscreen fix then stays on there).
A org.mozilla.firefox.systemconfig Flatpak extension of your own would conflict with the one this module provides.
Remove vrFullscreenFix when gamescope shows fullscreen X11 windows in VR, disableAv1 when a SteamOS kernel adds AV1 to iris.

How it works

Default prefs

The prefs are written with pref(), and nothing goes to prefs.js. Firefox reads default prefs from defaults/pref/*.js in its system config dir, which in the Flatpak is /app/etc/firefox, the mount point of the org.mozilla.firefox.systemconfig extension. home-manager provides that extension as a link from ~/.local/share/flatpak/extension/org.mozilla.firefox.systemconfig/aarch64/stable to a store directory; Flatpak mounts it itself, so the sandbox doesn't get /nix.

Desktop profile

The launcher's wrapper (modules/firefox/wrapper.nix) gets the entry's flatpak run … command line and, in the nested desktop, adds --profile <desktopProfile> (not to the profile manager action, --ProfileManager). The desktop profile undoes the fullscreen fix only while its Firefox runs: the wrapper links the profile's user.js to /app/etc/firefox/steam-frame-nix-desktop-user.js (a sandbox path) right before starting Firefox, waits for it, and once it has exited and the profile is no longer in use removes the link and the value Firefox stored from it in prefs.js. A second launch that just hands a URL to the running Firefox leaves both in place. After a crash (or if prefs.js can't be rewritten), the next launch or steam-frame-nix-cleanup (on switch) removes them.

Older versions

Older versions linked or copied a user.js into every profile; those and the values they left in prefs.js are removed by steam-frame-nix-cleanup on switch, for each profile not in use at that moment.

3.9 KiB Raw Permalink Blame History