fix(archsetup): use modalias for GPU detection instead of lspci

lspci parsing missed GPUs that report as "Display controller" instead
of "VGA" (e.g., AMD Strix Halo). Modalias-based detection checks vendor
IDs directly from /sys, which is more reliable and matches how the
kernel itself identifies hardware.

1 files changed, 44 insertions, 10 deletions

diff --git a/archsetup b/archsetup
index 8843488..6180b95 100755
--- a/archsetup
+++ b/archsetup
@@ -446,26 +446,60 @@ install_gpu_drivers() {
 
     display "subtitle" "GPU Drivers"
 
-    # Detect GPU vendors via lspci
-    gpu_info=$(lspci 2>/dev/null | grep -E "VGA|3D")
+    # Detect GPU vendors using modalias (more reliable than parsing lspci)
+    # Modalias is the kernel's hardware identification system used by drivers
+    # Vendor IDs: 1002=AMD, 8086=Intel, 10DE=NVIDIA
+    local detected_intel=false
+    local detected_amd=false
+    local detected_nvidia=false
+
+    # Primary detection: check modalias from DRM subsystem
+    for modalias_file in /sys/class/drm/card*/device/modalias; do
+        if [[ -r "$modalias_file" ]]; then
+            modalias=$(cat "$modalias_file" 2>/dev/null)
+            case "$modalias" in
+                *v00008086*) detected_intel=true ;;
+                *v00001002*) detected_amd=true ;;
+                *v000010DE*|*v000010de*) detected_nvidia=true ;;
+            esac
+        fi
+    done
+
+    # Fallback: check PCI bus modalias if DRM not available (early boot/chroot)
+    if ! $detected_intel && ! $detected_amd && ! $detected_nvidia; then
+        for modalias_file in /sys/bus/pci/devices/*/modalias; do
+            if [[ -r "$modalias_file" ]]; then
+                modalias=$(cat "$modalias_file" 2>/dev/null)
+                # Only check display class devices (bc03 = display controller)
+                if [[ "$modalias" == *bc03* ]]; then
+                    case "$modalias" in
+                        *v00008086*) detected_intel=true ;;
+                        *v00001002*) detected_amd=true ;;
+                        *v000010DE*|*v000010de*) detected_nvidia=true ;;
+                    esac
+                fi
+            fi
+        done
+    fi
 
-    if echo "$gpu_info" | grep -qi "intel"; then
-        display "task" "Intel GPU detected - installing drivers"
+    # Install drivers based on detected hardware
+    if $detected_intel; then
+        display "task" "Intel GPU detected (via modalias) - installing drivers"
         pacman_install mesa
         pacman_install intel-media-driver     # hardware video acceleration
         pacman_install vulkan-intel           # Vulkan support
     fi
 
-    if echo "$gpu_info" | grep -qi "amd\|radeon"; then
-        display "task" "AMD GPU detected - installing drivers"
+    if $detected_amd; then
+        display "task" "AMD GPU detected (via modalias) - installing drivers"
         pacman_install mesa
         pacman_install xf86-video-amdgpu
         pacman_install vulkan-radeon
         pacman_install libva-mesa-driver      # hardware video acceleration
     fi
 
-    if echo "$gpu_info" | grep -qi "nvidia"; then
-        display "task" "NVIDIA GPU detected - installing drivers"
+    if $detected_nvidia; then
+        display "task" "NVIDIA GPU detected (via modalias) - installing drivers"
         pacman_install nvidia-dkms            # DKMS version for kernel flexibility
         pacman_install nvidia-utils
         pacman_install nvidia-settings
@@ -473,8 +507,8 @@ install_gpu_drivers() {
     fi
 
     # Fallback for VMs or unknown hardware
-    if ! echo "$gpu_info" | grep -qiE "intel|amd|radeon|nvidia"; then
-        display "task" "No discrete GPU detected - installing generic drivers"
+    if ! $detected_intel && ! $detected_amd && ! $detected_nvidia; then
+        display "task" "No GPU detected via modalias - installing generic drivers"
         pacman_install mesa
         pacman_install xf86-video-vesa
     fi