ci: gate the virtual-device jobs behind a 'ci-virtual-device' PR label

The Windows and libusb virtual-device jobs install kernel drivers, so they
stay out of the per-push matrix. In addition to workflow_dispatch, they now
also run automatically on a pull request labelled 'ci-virtual-device'
(pull_request events use the PR head's workflow files for same-repo PRs, so
this works even before the workflows reach the default branch).

Also harden the libusb job's module setup: print which raw_gadget/dummy_hcd
modules the runner kernel actually ships and build dummy_hcd out-of-tree when
it isn't packaged. The test still self-skips if /dev/raw-gadget can't be
provided.

Assisted-by: Claude:claude-opus-4.8

Author: Youw

.github/workflows/libusb-vhid-test.yml

@@ -9,9 +9,15 @@ name: Linux libusb Virtual HID Device Test (manual)
 
 on:
   workflow_dispatch:
+  # Also runs automatically on a pull request that carries the
+  # 'ci-virtual-device' label (the job below is gated on that label).
+  pull_request:
+    types: [opened, reopened, labeled, synchronize]
 
 jobs:
   libusb-rawgadget:
+    # workflow_dispatch always runs; on a PR, only when the label is present.
+    if: github.event_name == 'workflow_dispatch' || contains(github.event.pull_request.labels.*.name, 'ci-virtual-device')
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4
@@ -24,22 +30,27 @@ jobs:
         sudo apt-get install -y libudev-dev libusb-1.0-0-dev build-essential cmake
         sudo apt-get install -y "linux-modules-extra-$(uname -r)" "linux-headers-$(uname -r)" || true
 
-    - name: Load raw_gadget and dummy_hcd
+    - name: Set up raw_gadget + dummy_hcd
       run: |
         set -x
+        echo "kernel: $(uname -r)"
+        # raw_gadget and dummy_hcd ship in linux-modules-extra on many kernel
+        # flavours; show what is actually available for this runner's kernel.
+        find "/lib/modules/$(uname -r)" \( -name 'raw_gadget*' -o -name 'dummy_hcd*' \) 2>/dev/null || true
         sudo modprobe raw_gadget || true
         sudo modprobe dummy_hcd || true
+        # dummy_hcd is not packaged by Ubuntu; build it out-of-tree if needed.
         if ! lsmod | grep -q dummy_hcd; then
-          echo "dummy_hcd not packaged; building out-of-tree..."
-          git clone --depth 1 https://github.com/xairy/raw-gadget.git rawgadget || true
-          if [ -d rawgadget/dummy_hcd ]; then
-            make -C rawgadget/dummy_hcd || true
-            sudo insmod rawgadget/dummy_hcd/dummy_hcd.ko || true
+          echo "Building dummy_hcd out-of-tree against $(uname -r) headers..."
+          git clone --depth 1 https://github.com/xairy/raw-gadget.git rg || true
+          if [ -d rg/dummy_hcd ]; then
+            make -C rg/dummy_hcd 2>&1 | tail -25 || true
+            sudo insmod rg/dummy_hcd/dummy_hcd.ko 2>&1 || true
           fi
         fi
         sudo modprobe raw_gadget || true
-        echo "--- modules ---"; lsmod | grep -E 'raw_gadget|dummy_hcd' || echo "(modules not fully loaded)"
-        ls -l /dev/raw-gadget || echo "/dev/raw-gadget not present -> test will self-skip"
+        echo "--- loaded ---"; lsmod | grep -E 'raw_gadget|dummy_hcd' || echo "(none loaded)"
+        ls -l /dev/raw-gadget 2>/dev/null || echo "/dev/raw-gadget absent -> DeviceIO_libusb will self-skip"
 
     - name: Configure + build (libusb backend + tests)
       run: |

.github/workflows/win-vhid-test.yml

@@ -9,9 +9,15 @@ name: Windows Virtual HID Device Test (manual)
 
 on:
   workflow_dispatch:
+  # Also runs automatically on a pull request that carries the
+  # 'ci-virtual-device' label (the job below is gated on that label).
+  pull_request:
+    types: [opened, reopened, labeled, synchronize]
 
 jobs:
   win-vhid:
+    # workflow_dispatch always runs; on a PR, only when the label is present.
+    if: github.event_name == 'workflow_dispatch' || contains(github.event.pull_request.labels.*.name, 'ci-virtual-device')
     runs-on: windows-latest
     steps:
     - uses: actions/checkout@v4