rework drm representation

sysfs/class_drm_card.go

@@ -11,58 +11,118 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//go:build !windows
 // +build !windows
 
 package sysfs
 
 import (
-	"errors"
+	"fmt"
 	"path/filepath"
-	"syscall"
 
 	"github.com/prometheus/procfs/internal/util"
 )
 
-type ClassDrmCard struct {
+const drmClassPath = "class/drm"
+
+// DrmCard contains info from files in /sys/class/drm for a
+// single DRM Card device.
+type DrmCard struct {
 	Name   string
-	Enable uint64
 	Driver string
+	Ports  map[string]DrmCardPort
+}
+
+// DrmCardPort contains info from files in
+// /sys/class/drm/<Card>/<Card>-<Name>
+// for a single port of one DrmCard device.
+type DrmCardPort struct {
+	Name    string
+	Status  string
+	Dpms    string
+	Enabled string
 }
 
-func (fs FS) ClassDrmCard() ([]ClassDrmCard, error) {
+// DrmCardClass is a collection of every Card device in
+// /sys/class/drm.
+//
+// The map keys are the names of the InfiniBand devices.
+type DrmCardClass map[string]DrmCard
+
+// DrmCardClass returns infos for all Drm devices read from
+// /sys/class/drm.
+func (fs FS) DrmCardClass() (DrmCardClass, error) {
+
 	cards, err := filepath.Glob(fs.sys.Path("class/drm/card[0-9]"))
+
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to list DRM card ports at %q: %w", cards, err)
+	}
+
+	drmCardClass := make(DrmCardClass, len(cards))
+	for _, c := range cards {
+		card, err := fs.parseDrmCard(filepath.Base(c))
+		if err != nil {
+			return nil, err
+		}
+
+		drmCardClass[card.Name] = *card
+	}
+
+	return drmCardClass, nil
+}
+
+// Parse one DrmCard.
+func (fs FS) parseDrmCard(name string) (*DrmCard, error) {
+	path := fs.sys.Path(drmClassPath, name)
+	card := DrmCard{Name: name}
+
+	// Read the kernel module of the card
+	cardDriverPath, err := filepath.EvalSymlinks(filepath.Join(path, "device/driver"))
+	if err != nil {
+		return nil, fmt.Errorf("failed to read driver: %w", err)
 	}
+	card.Driver = filepath.Base(cardDriverPath)
 
-	stats := make([]ClassDrmCard, 0, len(cards))
-	for _, card := range cards {
-		cardStats, err := parseClassDrmCard(card)
+	portsPath, err := filepath.Glob(filepath.Join(path, filepath.Base(path)+"-*-*"))
+
+	if err != nil {
+		return nil, fmt.Errorf("failed to list DRM card ports at %q: %w", portsPath, err)
+	}
+
+	card.Ports = make(map[string]DrmCardPort, len(portsPath))
+	for _, d := range portsPath {
+		port, err := parseDrmCardPort(d)
 		if err != nil {
-			if errors.Is(err, syscall.ENODATA) {
-				continue
-			}
 			return nil, err
 		}
-		cardStats.Name = filepath.Base(card)
-		stats = append(stats, cardStats)
+
+		card.Ports[port.Name] = *port
 	}
-	return stats, nil
+
+	return &card, nil
 }
 
-func parseClassDrmCard(port string) (ClassDrmCard, error) {
-	cardEnable, err := util.ReadIntFromFile(filepath.Join(port, "device/enable"))
+func parseDrmCardPort(port string) (*DrmCardPort, error) {
+	portStatus, err := util.SysReadFile(filepath.Join(port, "status"))
 	if err != nil {
-		return ClassDrmCard{}, err
+		return nil, err
+	}
+
+	drmCardPort := DrmCardPort{Name: filepath.Base(port), Status: portStatus}
+
+	portDpms, err := util.SysReadFile(filepath.Join(port, "dpms"))
+	if err != nil {
+		return nil, err
 	}
 
-	cardDriverPath, err := filepath.EvalSymlinks(filepath.Join(port, "device/driver"))
+	drmCardPort.Dpms = portDpms
+
+	portEnabled, err := util.SysReadFile(filepath.Join(port, "enabled"))
 	if err != nil {
-		return ClassDrmCard{}, err
+		return nil, err
 	}
+	drmCardPort.Enabled = portEnabled
 
-	return ClassDrmCard{
-		Enable: uint64(cardEnable),
-		Driver: filepath.Base(cardDriverPath),
-	}, nil
+	return &drmCardPort, nil
 }

sysfs/class_drm_card_test.go

@@ -17,8 +17,9 @@
 package sysfs
 
 import (
-	"reflect"
 	"testing"
+
+	"github.com/google/go-cmp/cmp"
 )
 
 func TestClassDRMCard(t *testing.T) {
@@ -27,25 +28,38 @@ func TestClassDRMCard(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	drmCardTest, err := fs.ClassDrmCard()
+	got, err := fs.DrmCardClass()
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	classDrmCard := []ClassDrmCard{
-		{
+	want := DrmCardClass{
+		"card0": DrmCard{
 			Name:   "card0",
-			Enable: 1,
 			Driver: "amdgpu",
+			Ports:  map[string]DrmCardPort{},
 		},
-		{
+		"card1": DrmCard{
 			Name:   "card1",
-			Enable: 1,
 			Driver: "i915",
+			Ports: map[string]DrmCardPort{
+				"card1-DP-1": {
+					Name:    "card1-DP-1",
+					Dpms:    "Off",
+					Enabled: "disabled",
+					Status:  "disconnected",
+				},
+				"card1-DP-5": {
+					Name:    "card1-DP-5",
+					Dpms:    "On",
+					Enabled: "enabled",
+					Status:  "connected",
+				},
+			},
 		},
 	}
 
-	if !reflect.DeepEqual(classDrmCard, drmCardTest) {
-		t.Errorf("Result not correct: want %v, have %v", classDrmCard, drmCardTest)
+	if diff := cmp.Diff(want, got); diff != "" {
+		t.Fatalf("unexpected DRMCard class (-want +got):\n%s", diff)
 	}
 }

testdata/fixtures.ttar

@@ -4958,6 +4958,34 @@ Mode: 755
 Directory: fixtures/sys/class/drm/card1/card1-DP-1
 Mode: 755
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: fixtures/sys/class/drm/card1/card1-DP-1/connector_id
+Lines: 1
+103
+Mode: 444
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: fixtures/sys/class/drm/card1/card1-DP-1/dpms
+Lines: 1
+Off
+Mode: 444
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: fixtures/sys/class/drm/card1/card1-DP-1/edid
+Lines: 0
+Mode: 444
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: fixtures/sys/class/drm/card1/card1-DP-1/enabled
+Lines: 1
+disabled
+Mode: 444
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: fixtures/sys/class/drm/card1/card1-DP-1/modes
+Lines: 0
+Mode: 444
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: fixtures/sys/class/drm/card1/card1-DP-1/status
+Lines: 1
+disconnected
+Mode: 644
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Directory: fixtures/sys/class/drm/card1/card1-DP-5
 Mode: 755
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -