graphics_card: add drm_node field (New) (#2341)

* graphics_card: add `drm_node` field

* resource: fix old Python support

* resource: add graphics_card drm_node tests

* black

Author: Saviq

providers/resource/bin/graphics_card_resource.py

@@ -20,8 +20,10 @@
 
 import argparse
 import collections
+from pathlib import Path
 import subprocess
 import shlex
+import sys
 
 from checkbox_support.helpers.slugify import slugify
 from checkbox_support.helpers.release_info import get_release_info
@@ -216,6 +218,21 @@ def main():
                 video_devices[0]["switch_to_cmd"] = switch_cmds[
                     record["driver"]
                 ][1]
+
+            cards = tuple(Path("/sys" + record["path"]).glob("drm/card*"))
+            if "name" in record and (Path("/dev/") / record["name"]).exists():
+                # DRM node named in the udev record
+                record["drm_node"] = Path("/dev/") / record["name"]
+            elif len(cards) == 1:
+                # Find the DRM node in device tree
+                record["drm_node"] = Path("/dev/dri") / cards[0].name
+            else:
+                sys.stderr.write(
+                    "Warning: could not find DRM node for device at path "
+                    "{path}\n".format(path=record["path"])
+                )
+                record["drm_node"] = ""
+
         # Finally, print the records
         for record in video_devices:
             items = [

providers/resource/tests/test_graphics_card_resource.py

@@ -18,12 +18,29 @@
 # along with Checkbox.  If not, see <http://www.gnu.org/licenses/>.
 
 import unittest
-from unittest.mock import patch
+from unittest.mock import patch, MagicMock
+from pathlib import Path
+from io import StringIO
 import graphics_card_resource
 
 
 class GraphicsCardResourceTests(unittest.TestCase):
 
+    def _run_main_with_udev_data(self, udev_data):
+        """Helper to run main() with mocked udev data."""
+        with patch("graphics_card_resource.parse_args") as mock_args, patch(
+            "graphics_card_resource.subprocess_lines_generator"
+        ) as mock_gen, patch(
+            "graphics_card_resource.sys.stderr", new_callable=StringIO
+        ) as mock_stderr, patch(
+            "builtins.print"
+        ):
+
+            mock_args.return_value = MagicMock(command="udev_resource.py")
+            mock_gen.return_value = iter(udev_data)
+            graphics_card_resource.main()
+            return mock_stderr.getvalue()
+
     @patch("graphics_card_resource.get_release_info")
     def test_compare_ubuntu_release_version(self, mock_release_info):
         mock_release_info.return_value = {"release": "24.04"}
@@ -57,6 +74,94 @@ def test_udev_devices_success(self):
         self.assertEqual(len(record_list), 1)
         self.assertEqual(record_list[0]["pci_device_name"], "0000:01:00.0")
 
+    def test_drm_node_from_udev_name(self):
+        """Test DRM node detection when name is in udev record."""
+        udev_data = [
+            "category: VIDEO",
+            "path: /devices/pci0000:00/0000:00:02.0",
+            "name: card0",
+            "",
+        ]
+
+        def path_factory(path_str):
+            mock_path = MagicMock(spec=Path)
+            if path_str.startswith("/sys"):
+                mock_path.glob.return_value = iter([])
+            elif path_str == "/dev/":
+                mock_result = MagicMock(spec=Path)
+                mock_result.exists.return_value = True
+                mock_path.__truediv__ = MagicMock(return_value=mock_result)
+            return mock_path
+
+        with patch("graphics_card_resource.Path", side_effect=path_factory):
+            stderr = self._run_main_with_udev_data(udev_data)
+        self.assertEqual(stderr, "")
+
+    def test_drm_node_single_card_in_sysfs(self):
+        """Test DRM node detection when exactly one card found in sysfs."""
+        udev_data = [
+            "category: VIDEO",
+            "path: /devices/pci0000:00/0000:00:02.0",
+            "",
+        ]
+
+        mock_card = MagicMock(spec=Path, name="card0")
+
+        def path_factory(path_str):
+            mock_path = MagicMock(spec=Path)
+            if path_str.startswith("/sys"):
+                mock_path.glob.return_value = iter([mock_card])
+            elif path_str == "/dev/dri":
+                mock_path.__truediv__ = MagicMock(
+                    return_value=MagicMock(spec=Path)
+                )
+            return mock_path
+
+        with patch("graphics_card_resource.Path", side_effect=path_factory):
+            stderr = self._run_main_with_udev_data(udev_data)
+        self.assertEqual(stderr, "")
+
+    def test_drm_node_warning_no_cards(self):
+        """Test DRM node detection when no cards found (warning case)."""
+        udev_data = [
+            "category: VIDEO",
+            "path: /devices/pci0000:00/0000:00:02.0",
+            "",
+        ]
+
+        def path_factory(path_str):
+            mock_path = MagicMock(spec=Path)
+            if path_str.startswith("/sys"):
+                mock_path.glob.return_value = iter([])
+            return mock_path
+
+        with patch("graphics_card_resource.Path", side_effect=path_factory):
+            stderr = self._run_main_with_udev_data(udev_data)
+        self.assertIn("Warning: could not find DRM node", stderr)
+        self.assertIn("/devices/pci0000:00/0000:00:02.0", stderr)
+
+    def test_drm_node_warning_multiple_cards(self):
+        """Test DRM node detection when multiple cards found (warning case)."""
+        udev_data = [
+            "category: VIDEO",
+            "path: /devices/pci0000:00/0000:00:02.0",
+            "",
+        ]
+
+        mock_card1 = MagicMock(spec=Path, name="card0")
+        mock_card2 = MagicMock(spec=Path, name="card1")
+
+        def path_factory(path_str):
+            mock_path = MagicMock(spec=Path)
+            if path_str.startswith("/sys"):
+                mock_path.glob.return_value = iter([mock_card1, mock_card2])
+            return mock_path
+
+        with patch("graphics_card_resource.Path", side_effect=path_factory):
+            stderr = self._run_main_with_udev_data(udev_data)
+        self.assertIn("Warning: could not find DRM node", stderr)
+        self.assertIn("/devices/pci0000:00/0000:00:02.0", stderr)
+
 
 if __name__ == "__main__":
     unittest.main()