Initial commit: rtw89-steam-frame DKMS wrapper

DKMS package that fetches the in-tree rtw89 source for the target kernel,
applies the steam-frame patches, and builds/installs the patched RTL8852CU
modules for the Valve Steam Frame wireless adapter.

- dkms.conf: module list + install locations
- build.sh: fetch (gregkh/linux) + patch + build + verify
- register.sh: clone upstream patches, stage into /usr/src, dkms add/build/install

GPL-2.0-only.

build.sh

@@ -0,0 +1,68 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# rtw89-steam-frame DKMS build step.
+#
+# Fetches the in-tree rtw89 source for the *target* kernel from gregkh/linux,
+# applies the steam-frame patches, and builds in the current directory.
+#
+# Invoked by DKMS:  CWD = DKMS build dir, $kernelver exported by DKMS.
+# Also runnable standalone:  kernelver=7.2.8-arch1-2 bash build.sh
+#
+# Exit non-zero on any failure so DKMS marks the build failed (module not
+# installed for that kernel -> kernel keeps its stock rtw89). See plan for
+# the modprobe.d recovery note.
+set -euo pipefail
+
+KVER="${kernelver:-${1:-}}"
+[ -n "$KVER" ] || { echo "ERROR: kernelver not set (DKMS exports it; else pass as \$1)"; exit 1; }
+BASE="${KVER%%-*}"
+TAG="v${BASE%.0}"
+HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+BUILD="${PWD}"
+KBUILD="/lib/modules/$KVER/build"
+API="https://api.github.com/repos/gregkh/linux/contents/drivers/net/wireless/realtek/rtw89?ref=$TAG"
+MODS="rtw89_8852cu rtw89_usb rtw89_8852c rtw89_core"
+
+echo "== rtw89-steam-frame DKMS build: kernel=$KVER tag=$TAG =="
+[ -d "$KBUILD" ] || { echo "ERROR: kernel headers missing at $KBUILD (install linux-headers-$KVER)"; exit 1; }
+
+# clear any previous fetch leftovers
+find "$BUILD" -maxdepth 1 -type f \( -name '*.c' -o -name '*.h' -o -name 'Kconfig' -o -name 'Makefile' -o -name '*.files' \) -delete 2>/dev/null || true
+
+echo "-- fetch rtw89 source for $TAG (gregkh/linux)"
+curl -sf "$API" | python3 -c '
+import json, sys
+for f in json.load(sys.stdin):
+    if f["type"] == "file":
+        print(f["name"], f["download_url"])' > "$BUILD/rtw89.files"
+n=$(wc -l < "$BUILD/rtw89.files")
+[ "$n" -gt 0 ] || { echo "ERROR: no source files for $TAG (network? tag missing?)"; exit 1; }
+(cd "$BUILD" && xargs -P 8 -n 2 sh -c 'curl -sf -o "$0" "$1"' < rtw89.files) \
+  || { echo "ERROR: source download failed"; exit 1; }
+[ "$(ls "$BUILD"/*.c "$BUILD"/*.h 2>/dev/null | wc -l)" -gt 0 ] || { echo "ERROR: download incomplete"; exit 1; }
+
+echo "-- apply patches"
+for p in "$HERE"/patches/*.patch; do
+  if ! (cd "$BUILD" && patch -p1 --no-backup-if-mismatch -s < "$p"); then
+    echo "ERROR: $(basename "$p") does not apply to $TAG"
+    echo "  -> module NOT built for $KVER; kernel stock rtw89 will be used."
+    echo "  -> RECOVERY: remove /etc/modprobe.d/rtw89-steam-frame.conf before reloading WiFi"
+    exit 1
+  fi
+  echo "  applied $(basename "$p")"
+done
+
+echo "-- build against $KVER headers"
+make -s -j"$(nproc)" -C "$KBUILD" M="$BUILD" modules 2>&1 \
+  | grep -vE 'BTF|pahole|was built with|You are using \(out of date\)' || true
+
+for m in $MODS; do
+  [ -f "$BUILD/$m.ko" ] || { echo "ERROR: $m.ko not produced"; exit 1; }
+done
+grep -q 'parm: *reg6_pwr_override:' <<< "$(modinfo "$BUILD/rtw89_core.ko")" \
+  || { echo "ERROR: patched param reg6_pwr_override missing -> wrong/old source"; exit 1; }
+[ "$(modinfo -F vermagic "$BUILD/rtw89_core.ko" | cut -d' ' -f1)" = "$KVER" ] \
+  || { echo "ERROR: vermagic mismatch ($(modinfo -F vermagic "$BUILD/rtw89_core.ko" | cut -d' ' -f1) != $KVER)"; exit 1; }
+
+echo "== BUILD OK: $(ls "$BUILD"/rtw89_*.ko | wc -l) module files for $KVER =="