test: nvidia-hardware-test.sh to check, apply and visually verify the NVIDIA fix on a real PC

CHANGELOG.md

@@ -10,6 +10,7 @@ one per merged pull request.
 - **feat: the SteamOS conversion fixes a corrupted gaming mode screen with an NVIDIA GPU: nvidia-drm.modeset=1 and fbdev=1 on the kernel command line, NVIDIA modules in the initramfs (lib/nvidia.sh)**
 - **test: tests/nvidia-test.sh runs the NVIDIA fix against a fake RTX 5080 beside an iGPU, a stub modinfo and temp copies of the Limine, systemd-boot and GRUB files (no root, VM or hardware); NVIDIA_DRM_DIR points detection at a fake sysfs tree**
 - **fix: NVIDIA fix on Limine edits the KERNEL_CMDLINE[default] line (an appended += line ended up as literal text on the kernel command line, found in a VM); the modules are only loaded early when every installed kernel has them, and a Limine boot entry without the parameters is an error**
+- **test: tests/nvidia-hardware-test.sh for a real NVIDIA PC: check (read-only state of the detection, the live nvidia_drm modeset/fbdev, versions), apply, and visual (was the gaming mode picture clean), with a report file to paste**
 
 ## 2.9.6 - 2026-09-30
 

TECHNICAL.md

@@ -222,7 +222,10 @@ has the NVIDIA modules (mkinitcpio fails on a missing module, and
 On Limine the parameters go into the existing `KERNEL_CMDLINE[default]="..."`
 line: an extra appended `+=` line is pasted into the command line as text.
 Only what's missing is changed; it applies after a reboot. Turning
-the conversion off removes both. Untested on hardware so far.
+the conversion off removes both. `tests/nvidia-test.sh` tests it against a fake GPU
+and fake boot loader files; `tests/nvidia-hardware-test.sh check|apply|visual` is for a
+real NVIDIA PC (read-only check, the real apply, and a prompt for whether the picture
+was clean), and writes `~/steamify-nvidia-report.txt`.
 
 ## HDMI-CEC
 

tests/nvidia-hardware-test.sh

@@ -0,0 +1,87 @@
+#!/bin/bash
+# Test of the NVIDIA fix on a real PC with an NVIDIA GPU (the unit test fakes
+# one: tests/nvidia-test.sh). Run from the Steamify checkout:
+#   bash tests/nvidia-hardware-test.sh check    read-only: what is detected, what the live kernel uses, what apply would change
+#   bash tests/nvidia-hardware-test.sh apply    really applies the fix (sudo), then reboot and run check again
+#   bash tests/nvidia-hardware-test.sh visual   after trying gaming mode: was the picture clean? (asks you)
+# Every run appends to ~/steamify-nvidia-report.txt: paste that file when asking for help.
+cd "$(dirname "$0")/.." || exit 1
+REPORT="${NVIDIA_REPORT:-$HOME/steamify-nvidia-report.txt}"
+source lib/common.sh; source lib/hdmi-refresh.sh; source lib/nvidia.sh
+mode="${1:-check}"
+fail=0
+say() { echo "$*" | tee -a "$REPORT"; }
+pass() { say "PASS $*"; }
+bad()  { say "FAIL $*"; fail=1; }
+note() { say "     $*"; }
+root_cat() { cat "$1" 2>/dev/null || sudo cat "$1" 2>/dev/null || echo "(unreadable)"; }
+
+say ""; say "===== $(date '+%F %T')  mode=$mode  kernel=$(uname -r)"
+
+report_system() {
+    say "-- GPU and software"
+    lspci -nn 2>/dev/null | grep -iE 'vga|3d|display' | while read -r l; do note "$l"; done
+    command -v nvidia-smi >/dev/null && note "driver: $(nvidia-smi --query-gpu=name,driver_version --format=csv,noheader 2>&1 | head -n 1)"
+    for p in nvidia-open nvidia-utils nvidia-dkms gamescope gamescope-session-cachyos linux-cachyos-nvidia-open; do
+        v="$(pacman -Q "$p" 2>/dev/null)" && note "$v"
+    done
+    note "boot loader file: $(nvidia_boot_file || true)"
+    note "cmdline: $(cat /proc/cmdline)"
+}
+
+check_state() {
+    say "-- Steamify's view"
+    if nvidia_present; then pass "an NVIDIA GPU with its driver is detected"; else bad "no NVIDIA GPU/driver detected: the fix does nothing here"; fi
+    local p
+    for p in $NVIDIA_PARAMS; do
+        if grep -qw -- "$p" /proc/cmdline; then pass "$p is on the running kernel's command line"
+        elif nvidia_param_set "$p"; then bad "$p is in the boot loader's file but not booted yet: reboot"
+        else bad "$p is missing (run: bash tests/nvidia-hardware-test.sh apply)"; fi
+    done
+    say "-- the live NVIDIA driver"
+    local m
+    for m in modeset fbdev; do
+        v="$(root_cat /sys/module/nvidia_drm/parameters/$m)"
+        if [[ "$v" == Y ]]; then pass "nvidia_drm $m = Y"; else bad "nvidia_drm $m = $v (want Y)"; fi
+    done
+    lsmod | grep -q '^nvidia_drm' && pass "nvidia_drm is loaded" || bad "nvidia_drm is not loaded"
+    local c found=0
+    for c in /sys/class/drm/card[0-9]*/device; do
+        [[ "$(cat "$c/vendor" 2>/dev/null)" == 0x10de ]] || continue
+        found=1; note "NVIDIA card: ${c%/device} driver=$(basename "$(readlink -f "$c/driver" 2>/dev/null)")"
+        for s in "${c%/device}"/card*-*/status; do [[ -f "$s" ]] && note "  $(basename "$(dirname "$s")"): $(cat "$s")"; done
+    done
+    [[ $found == 1 ]] || bad "no NVIDIA card in /sys/class/drm"
+    say "-- initramfs"
+    if nvidia_modules_everywhere; then note "every installed kernel has nvidia_drm: the early-load drop-in is used"
+    else note "not every installed kernel has nvidia_drm: the early-load drop-in is skipped (parameters still apply)"; fi
+    nvidia_initramfs_ok && note "NVIDIA modules are in the initramfs config" || note "NVIDIA modules are not in the initramfs config"
+    say "-- what apply would change"
+    if nvidia_params_missing; then note "adds $NVIDIA_PARAMS to $(nvidia_boot_file)"; else note "kernel parameters: nothing to change"; fi
+    if ! nvidia_initramfs_ok && nvidia_modules_everywhere; then note "writes $NVIDIA_INITRAMFS_CONF"; fi
+}
+
+case "$mode" in
+    check)
+        report_system; check_state ;;
+    apply)
+        report_system
+        say "-- applying"
+        if nvidia_enable 2>&1 | tee -a "$REPORT"; [[ ${PIPESTATUS[0]} == 0 ]]; then pass "nvidia_enable finished"
+        else bad "nvidia_enable failed (output above)"; fi
+        say "Now reboot, then run: bash tests/nvidia-hardware-test.sh check" ;;
+    visual)
+        report_system
+        say "-- try gaming mode now (log in to it or reboot into it), look at the screen, then answer"
+        read -rp "Is the gaming mode picture clean (no corruption, no flicker)? [y/n/partly] " a
+        read -rp "What did you see (one line, e.g. 'garbled colours at start, fine after login')? " what
+        say "visual result: $a: $what"
+        [[ "$a" == y ]] && pass "picture clean" || bad "picture not clean ($a)"
+        say "-- gamescope and NVIDIA lines from this boot's log"
+        { journalctl -b --no-pager 2>/dev/null || sudo journalctl -b --no-pager 2>/dev/null; } |
+            grep -iE 'gamescope|nvidia|drm|nvrm|wlserver|vulkan' | tail -n 80 | tee -a "$REPORT" | tail -n 5
+        note "(more in $REPORT)" ;;
+    *) echo "usage: $0 check|apply|visual"; exit 2 ;;
+esac
+say ""; say "Report: $REPORT"
+exit $fail