Merge pull request #23 from theupriser/fix/fremont-cec

fix: HDMI-CEC on the Steam Machine

AGENTS.md

@@ -188,6 +188,14 @@ gamescope and the Plasma desktop. Primary target: the Valve Steam Machine
   newline. Build the EDID from the DDC read, not from sysfs: a live override
   replaces the kernel's copy. The kernel command-line value holds a path, so
   `sed` uses `|` as its delimiter.
+- Steam Machine CEC driver (`cec_driver_enable`, `lib/cec.sh`): mainline
+  `cros_ec_cec` lacks Fremont, so HDMI-CEC builds Valve's copy (evlaV
+  `linux-integration`, pinned commit + SHA-256) with DKMS for every kernel.
+  It's patched to register its notifier without a port name when the board
+  has one CEC port: amdgpu registers its HDMI notifier nameless, and the
+  kernel only pairs that with a named lookup ("Port C") when the CEC driver
+  registered first, which never happens since amdgpu loads from the
+  initramfs. Without it `/dev/cec0` exists but stays at `f.f.f.f`.
 - `Relogin=true` means a gamescope that fails to start is relaunched in a
   tight loop; keep that in mind when changing session handling.
 

CHANGELOG.md

@@ -5,9 +5,24 @@ All notable changes, per version and per commit. Versions follow
 `steamify.sh`. Versions before 0.7.0 were numbered afterwards,
 one per merged pull request.
 
+## 2.0.3 - 2026-09-26
+
+- **fix: HDMI-CEC on the Steam Machine**
+  - Mainline's `cros_ec_cec` driver doesn't know the Steam Machine, so there
+    was no `/dev/cec0`. HDMI-CEC now builds Valve's version of the driver
+    with DKMS (`steamify-cros-ec-cec`) for every installed kernel, with a fix
+    so it finds amdgpu's HDMI port even though amdgpu loads first. An
+    existing HDMI-CEC install is ticked in the menu to add it.
+
+## 2.0.2 - 2026-09-26
+
+- **badfd84 docs: Non-affiliation disclaimer in the README**
+  - States that the project isn't affiliated with Valve or CachyOS, and that
+    Steam and SteamOS are Valve's trademarks.
+
 ## 2.0.1 - 2026-09-25
 
-- **feat: The Steamify shortcut opens the app**
+- **2b3f1de feat: The Steamify shortcut opens the app**
   - "Steamify CachyOS" on the desktop and in the launcher starts the newest
     app (in Konsole the first time, if PySide6 still has to be installed).
     The terminal menu is "Steamify Terminal" in the launcher. A shortcut from

README.md

@@ -131,3 +131,11 @@ Contributing (or an AI agent)? Read [AGENTS.md](AGENTS.md).
 ## License
 
 MIT - do whatever you want with it. See [LICENSE.md](LICENSE.md).
+
+## Disclaimer
+
+Steamify CachyOS is an unofficial community project. It is not affiliated
+with, endorsed by, or sponsored by Valve Corporation or the CachyOS project.
+Steam, SteamOS and the Steam logo are trademarks of Valve Corporation. CachyOS
+is the name of its respective project. They are used here only to describe
+what this script works with.

lib/cec.sh

@@ -3,8 +3,9 @@
 # volume control (cec-audio-control) and the units that attach USB CEC
 # adapters (Pulse-Eight, RainShadow) with inputattach. They're only in
 # Valve's SteamOS (holo) repository, not in CachyOS or the AUR. Works with
-# any /dev/cec*: a GPU with CEC (e.g. the Steam Machine) or a USB adapter.
+# any /dev/cec*: a GPU with CEC or a USB adapter. On a Steam Machine it also
-# On a Steam Machine, steamos-manager configures cecd from Steam's settings.
+# builds Valve's CEC driver (see cec_driver_enable), and steamos-manager
+# configures cecd from Steam's settings.
 # Sourced by steamify.sh; not meant to be run on its own.
 
 CEC_PKGS=(cecd cec-audio-control inputattach-cec-units)
@@ -16,6 +17,15 @@ CEC_ORDER_DROPIN=/etc/systemd/user/steamos-manager.service.d/10-steamify-after-c
 # file. A later EnvironmentFile= overrides it.
 CEC_STEAM_ENV=/etc/steamify/steam-cec.env
 CEC_STEAM_DROPIN=/etc/systemd/user/steam-launcher.service.d/10-steamify-cec.conf
+# The Steam Machine's CEC runs through its embedded controller (cros_ec_cec).
+# Mainline's driver doesn't list Fremont, so there's no /dev/cec0; Valve's
+# kernel does. We build Valve's copy with DKMS for every kernel, pinned to a
+# reviewed commit.
+CEC_DKMS_NAME=steamify-cros-ec-cec
+CEC_DKMS_VER=1
+CEC_DKMS_SRC="/usr/src/$CEC_DKMS_NAME-$CEC_DKMS_VER"
+CEC_DRIVER_URL="https://raw.githubusercontent.com/evlaV/linux-integration/10c8c8800ccd3ae359203b4eefb6479f613b3b8e/drivers/media/cec/platform/cros-ec/cros-ec-cec.c"
+CEC_DRIVER_SHA256=e89fd4e87fceb32d713ffc59b64794779b3c2b3c012b0e2f2e9f0c40b42f4373
 
 cec_link_steamos_manager() {
     # On a Steam Machine: steamos-manager writes cecd's config from Steam's
@@ -33,9 +43,69 @@ cec_link_steamos_manager() {
 }
 
 cec_installed() { pacman -Q "${CEC_PKGS[@]}" >/dev/null 2>&1; }
-# On = installed and Steam told to show its CEC settings. An install from
+cec_driver_ok() { ! detect_valve_fremont || [[ -d "$CEC_DKMS_SRC" ]]; }
-# before 1.1.3 lacks the latter; the menu then ticks it (see cec_repair).
+# On = installed, Steam told to show its CEC settings and, on a Steam
-cec_status() { cec_installed && [[ -f "$CEC_STEAM_DROPIN" ]]; }
+# Machine, the driver built. An install from before 1.1.3 (settings) or
+# 2.0.3 (driver) lacks one; the menu then ticks it (see cec_repair).
+cec_status() { cec_installed && [[ -f "$CEC_STEAM_DROPIN" ]] && cec_driver_ok; }
+
+cec_reload_driver() {
+    # cecd keeps /dev/cec0 open, so the old module can't be unloaded under it.
+    systemctl --user stop cecd.service 2>/dev/null
+    sudo modprobe -r cros_ec_cec 2>/dev/null
+    sudo modprobe cros_ec_cec 2>/dev/null
+    systemctl --user start cecd.service 2>/dev/null
+}
+
+cec_driver_enable() {
+    detect_valve_fremont || return 0
+    local tmp k
+    if ! pacman -Q dkms >/dev/null 2>&1; then
+        sudo pacman -S --needed --noconfirm dkms || { err "Installing dkms failed."; return 1; }
+    fi
+    install_kernel_headers || return 1
+    tmp="$(mktemp -d)"
+    info "Downloading Valve's Steam Machine CEC driver..."
+    if ! curl -fsL "$CEC_DRIVER_URL" -o "$tmp/cros-ec-cec.c" ||
+        ! echo "$CEC_DRIVER_SHA256  $tmp/cros-ec-cec.c" | sha256sum -c --quiet -; then
+        rm -rf "$tmp"
+        err "Downloading Valve's CEC driver failed (or its checksum didn't match)."
+        return 1
+    fi
+    # amdgpu registers its HDMI notifier without a port name, which only
+    # matches the driver's named lookup ("Port C") if the driver loaded
+    # first; amdgpu loads from the initramfs, so it never does. With a
+    # single CEC port, look it up by device alone.
+    sed -i 's/cec_notifier_cec_adap_register(hdmi_dev, conns\[port_num\],/cec_notifier_cec_adap_register(hdmi_dev, conns[1] ? conns[port_num] : NULL,/' \
+        "$tmp/cros-ec-cec.c"
+    grep -q 'conns\[1\] ? conns\[port_num\] : NULL' "$tmp/cros-ec-cec.c" ||
+        { rm -rf "$tmp"; err "Patching Valve's CEC driver failed."; return 1; }
+    echo 'obj-m += cros-ec-cec.o' >"$tmp/Makefile"
+    printf '%s\n' "# Written by Steamify: Valve's cros_ec_cec, which knows the Steam Machine." \
+        "PACKAGE_NAME=\"$CEC_DKMS_NAME\"" "PACKAGE_VERSION=\"$CEC_DKMS_VER\"" \
+        'BUILT_MODULE_NAME[0]="cros-ec-cec"' 'DEST_MODULE_LOCATION[0]="/updates/dkms"' \
+        'AUTOINSTALL="yes"' >"$tmp/dkms.conf"
+    sudo dkms remove "$CEC_DKMS_NAME/$CEC_DKMS_VER" --all >/dev/null 2>&1
+    sudo rm -rf "$CEC_DKMS_SRC"
+    sudo install -d "$CEC_DKMS_SRC" && sudo install -m644 "$tmp"/{cros-ec-cec.c,Makefile,dkms.conf} "$CEC_DKMS_SRC/"
+    rm -rf "$tmp"
+    sudo dkms add "$CEC_DKMS_NAME/$CEC_DKMS_VER" >/dev/null || { err "Adding the CEC driver to DKMS failed."; return 1; }
+    # Every kernel with headers; one that fails to build only lacks CEC.
+    for k in /usr/lib/modules/*/build; do
+        k="$(basename "$(dirname "$k")")"
+        info "Building the CEC driver for $k..."
+        sudo dkms install "$CEC_DKMS_NAME/$CEC_DKMS_VER" -k "$k" >/dev/null ||
+            warn "Building the CEC driver for $k failed; that kernel has no HDMI-CEC."
+    done
+    cec_reload_driver
+}
+
+cec_driver_disable() {
+    [[ -d "$CEC_DKMS_SRC" ]] || return 0
+    sudo dkms remove "$CEC_DKMS_NAME/$CEC_DKMS_VER" --all >/dev/null 2>&1
+    sudo rm -rf "$CEC_DKMS_SRC"
+    cec_reload_driver
+}
 cec_repair() { cec_installed && ! cec_status; }
 
 fetch_holo_pkg() {
@@ -79,6 +149,7 @@ cec_enable() {
         return 1
     fi
     rm -rf "$tmp"
+    cec_driver_enable || return 1
     # Its udev rule gives the user /dev/cec*; cecd starts with the graphical
     # session, after steamos-manager wrote its config from Steam's settings.
     sudo udevadm control --reload
@@ -108,6 +179,7 @@ cec_disable() {
     systemctl --user disable --now cecd.service cec-audio-control.socket cec-audio-control.service 2>/dev/null
     systemctl --user disable steamos-manager-configure-cecd.service 2>/dev/null
     sudo pacman -Rns --noconfirm "${CEC_PKGS[@]}" 2>/dev/null
+    cec_driver_disable
     sudo rm -f "$CEC_ORDER_DROPIN" "$CEC_STEAM_DROPIN" "$CEC_STEAM_ENV"
     sudo rmdir "$(dirname "$CEC_ORDER_DROPIN")" "$(dirname "$CEC_STEAM_DROPIN")" "$(dirname "$CEC_STEAM_ENV")" 2>/dev/null
     systemctl --user daemon-reload

steamify.sh

@@ -15,7 +15,7 @@
 set -uo pipefail
 
 # Release version, see CHANGELOG.md.
-VERSION=2.0.1
+VERSION=2.0.3
 
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"