kms: Discover all available planes

Task-number: QTBUG-63058
Change-Id: I655384916bedbeb0da516e2eaa177d1128272d1c
Reviewed-by: Andy Nichols <andy.nichols@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

2 files changed, 205 insertions, 0 deletions

diff --git a/src/platformsupport/kmsconvenience/qkmsdevice.cpp b/src/platformsupport/kmsconvenience/qkmsdevice.cpp
index e1f2459bc0..48ad984bf5 100644
--- a/src/platformsupport/kmsconvenience/qkmsdevice.cpp
+++ b/src/platformsupport/kmsconvenience/qkmsdevice.cpp
@@ -384,6 +384,20 @@ QPlatformScreen *QKmsDevice::createScreenForConnector(drmModeResPtr resources,
     output.drm_format = drmFormat;
     output.clone_source = cloneSource;
 
+    QString planeListStr;
+    for (const QKmsPlane &plane : qAsConst(m_planes)) {
+        if (plane.possibleCrtcs & (1 << output.crtc_index)) {
+            output.available_planes.append(plane);
+            planeListStr.append(QString::number(plane.id));
+            planeListStr.append(QLatin1Char(' '));
+        }
+    }
+    qCDebug(qLcKmsDebug, "Output %s can use %d planes: %s",
+            connectorName.constData(), output.available_planes.count(), qPrintable(planeListStr));
+
+    // This is for the EGLDevice/EGLStream backend. On some of those devices one
+    // may want to target a pre-configured plane. It is probably useless for
+    // eglfs_kms and others. Do not confuse with generic plane support (available_planes).
     bool ok;
     int idx = qEnvironmentVariableIntValue("QT_QPA_EGLFS_KMS_PLANE_INDEX", &ok);
     if (ok) {
@@ -504,12 +518,16 @@ void QKmsDevice::createScreens()
         }
     }
 
+    drmSetClientCap(m_dri_fd, DRM_CLIENT_CAP_UNIVERSAL_PLANES, 1);
+
     drmModeResPtr resources = drmModeGetResources(m_dri_fd);
     if (!resources) {
         qErrnoWarning(errno, "drmModeGetResources failed");
         return;
     }
 
+    discoverPlanes();
+
     QVector<OrderedScreen> screens;
 
     int wantedConnectorIndex = -1;
@@ -628,6 +646,116 @@ void QKmsDevice::registerScreenCloning(QPlatformScreen *screen,
     Q_UNUSED(screensCloningThisScreen);
 }
 
+// drm_property_type_is is not available in old headers
+static inline bool propTypeIs(drmModePropertyPtr prop, uint32_t type)
+{
+    if (prop->flags & DRM_MODE_PROP_EXTENDED_TYPE)
+        return (prop->flags & DRM_MODE_PROP_EXTENDED_TYPE) == type;
+    return prop->flags & type;
+}
+
+void QKmsDevice::enumerateProperties(drmModeObjectPropertiesPtr objProps, PropCallback callback)
+{
+    for (uint32_t propIdx = 0; propIdx < objProps->count_props; ++propIdx) {
+        drmModePropertyPtr prop = drmModeGetProperty(m_dri_fd, objProps->props[propIdx]);
+        if (!prop)
+            continue;
+
+        const quint64 value = objProps->prop_values[propIdx];
+        qCDebug(qLcKmsDebug, "  property %d: id = %u name = '%s'", propIdx, prop->prop_id, prop->name);
+
+        if (propTypeIs(prop, DRM_MODE_PROP_SIGNED_RANGE)) {
+            qCDebug(qLcKmsDebug, "  type is SIGNED_RANGE, value is %lld, possible values are:", qint64(value));
+            for (int i = 0; i < prop->count_values; ++i)
+                qCDebug(qLcKmsDebug, "    %lld", qint64(prop->values[i]));
+        } else if (propTypeIs(prop, DRM_MODE_PROP_RANGE)) {
+            qCDebug(qLcKmsDebug, "  type is RANGE, value is %llu, possible values are:", value);
+            for (int i = 0; i < prop->count_values; ++i)
+                qCDebug(qLcKmsDebug, "    %llu", quint64(prop->values[i]));
+        } else if (propTypeIs(prop, DRM_MODE_PROP_ENUM)) {
+            qCDebug(qLcKmsDebug, "  type is ENUM, value is %llu, possible values are:", value);
+            for (int i = 0; i < prop->count_enums; ++i)
+                qCDebug(qLcKmsDebug, "    enum %d: %s - %llu", i, prop->enums[i].name, prop->enums[i].value);
+        } else if (propTypeIs(prop, DRM_MODE_PROP_BITMASK)) {
+            qCDebug(qLcKmsDebug, "  type is BITMASK, value is %llu, possible bits are:", value);
+            for (int i = 0; i < prop->count_enums; ++i)
+                qCDebug(qLcKmsDebug, "    bitmask %d: %s - %u", i, prop->enums[i].name, 1 << prop->enums[i].value);
+        } else if (propTypeIs(prop, DRM_MODE_PROP_BLOB)) {
+            qCDebug(qLcKmsDebug, "  type is BLOB");
+        } else if (propTypeIs(prop, DRM_MODE_PROP_OBJECT)) {
+            qCDebug(qLcKmsDebug, "  type is OBJECT");
+        }
+
+        callback(prop, value);
+
+        drmModeFreeProperty(prop);
+    }
+}
+
+void QKmsDevice::discoverPlanes()
+{
+    m_planes.clear();
+
+    drmModePlaneResPtr planeResources = drmModeGetPlaneResources(m_dri_fd);
+    if (!planeResources)
+        return;
+
+    const int countPlanes = planeResources->count_planes;
+    qCDebug(qLcKmsDebug, "Found %d planes", countPlanes);
+    for (int planeIdx = 0; planeIdx < countPlanes; ++planeIdx) {
+        drmModePlanePtr drmplane = drmModeGetPlane(m_dri_fd, planeResources->planes[planeIdx]);
+        if (!drmplane) {
+            qCDebug(qLcKmsDebug, "Failed to query plane %d, ignoring", planeIdx);
+            continue;
+        }
+
+        QKmsPlane plane;
+        plane.id = drmplane->plane_id;
+        plane.possibleCrtcs = drmplane->possible_crtcs;
+
+        const int countFormats = drmplane->count_formats;
+        QString formatStr;
+        for (int i = 0; i < countFormats; ++i) {
+            uint32_t f = drmplane->formats[i];
+            plane.supportedFormats.append(f);
+            QString s;
+            s.sprintf("%c%c%c%c ", f, f >> 8, f >> 16, f >> 24);
+            formatStr += s;
+        }
+
+        qCDebug(qLcKmsDebug, "plane %d: id = %u countFormats = %d possibleCrtcs = 0x%x supported formats = %s",
+                planeIdx, plane.id, countFormats, plane.possibleCrtcs, qPrintable(formatStr));
+
+        drmModeFreePlane(drmplane);
+
+        drmModeObjectPropertiesPtr objProps = drmModeObjectGetProperties(m_dri_fd, plane.id, DRM_MODE_OBJECT_PLANE);
+        if (!objProps) {
+            qCDebug(qLcKmsDebug, "Failed to query plane %d object properties, ignoring", planeIdx);
+            continue;
+        }
+
+        enumerateProperties(objProps, [this, &plane](drmModePropertyPtr prop, quint64 value) {
+            if (!strcmp(prop->name, "type")) {
+                plane.type = QKmsPlane::Type(value);
+            } else if (!strcmp(prop->name, "rotation")) {
+                plane.initialRotation = QKmsPlane::Rotations(int(value));
+                plane.availableRotations = 0;
+                if (propTypeIs(prop, DRM_MODE_PROP_BITMASK)) {
+                    for (int i = 0; i < prop->count_enums; ++i)
+                        plane.availableRotations |= QKmsPlane::Rotation(1 << prop->enums[i].value);
+                }
+                plane.rotationPropertyId = prop->prop_id;
+            }
+        });
+
+        m_planes.append(plane);
+
+        drmModeFreeObjectProperties(objProps);
+    }
+
+    drmModeFreePlaneResources(planeResources);
+}
+
 int QKmsDevice::fd() const
 {
     return m_dri_fd;
diff --git a/src/platformsupport/kmsconvenience/qkmsdevice_p.h b/src/platformsupport/kmsconvenience/qkmsdevice_p.h
index 872104e49d..5eecedec39 100644
--- a/src/platformsupport/kmsconvenience/qkmsdevice_p.h
+++ b/src/platformsupport/kmsconvenience/qkmsdevice_p.h
@@ -61,6 +61,41 @@
 #include <xf86drmMode.h>
 #include <drm_fourcc.h>
 
+#include <functional>
+
+// In less fortunate cases one may need to build on a system with dev headers
+// from the dark ages. Let's pull a GL and define the missing stuff outselves.
+
+#ifndef DRM_PLANE_TYPE_OVERLAY
+#define DRM_PLANE_TYPE_OVERLAY 0
+#endif
+#ifndef DRM_PLANE_TYPE_PRIMARY
+#define DRM_PLANE_TYPE_PRIMARY 1
+#endif
+#ifndef DRM_PLANE_TYPE_CURSOR
+#define DRM_PLANE_TYPE_CURSOR 2
+#endif
+
+#ifndef DRM_CLIENT_CAP_UNIVERSAL_PLANES
+#define DRM_CLIENT_CAP_UNIVERSAL_PLANES 2
+#endif
+#ifndef DRM_CLIENT_CAP_ATOMIC
+#define DRM_CLIENT_CAP_ATOMIC 3
+#endif
+
+#ifndef DRM_MODE_PROP_EXTENDED_TYPE
+#define DRM_MODE_PROP_EXTENDED_TYPE 0x0000ffc0
+#endif
+#ifndef DRM_MODE_PROP_TYPE
+#define DRM_MODE_PROP_TYPE(n) ((n) << 6)
+#endif
+#ifndef DRM_MODE_PROP_OBJECT
+#define DRM_MODE_PROP_OBJECT DRM_MODE_PROP_TYPE(1)
+#endif
+#ifndef DRM_MODE_PROP_SIGNED_RANGE
+#define DRM_MODE_PROP_SIGNED_RANGE DRM_MODE_PROP_TYPE(2)
+#endif
+
 QT_BEGIN_NAMESPACE
 
 class QKmsDevice;
@@ -99,6 +134,42 @@ private:
     QMap<QString, QVariantMap> m_outputSettings;
 };
 
+// NB! QKmsPlane does not store the current state and offers no functions to
+// change object properties. Any such functionality belongs to subclasses since
+// in some cases atomic operations will be desired where a mere
+// drmModeObjectSetProperty would not be acceptable.
+struct QKmsPlane
+{
+    enum Type {
+        OverlayPlane = DRM_PLANE_TYPE_OVERLAY,
+        PrimaryPlane = DRM_PLANE_TYPE_PRIMARY,
+        CursorPlane = DRM_PLANE_TYPE_CURSOR
+    };
+
+    enum Rotation {
+        Rotation0 = 1 << 0,
+        Rotation90 = 1 << 1,
+        Rotation180 = 1 << 2,
+        Rotation270 = 1 << 3,
+        RotationReflectX = 1 << 4,
+        RotationReflectY = 1 << 5
+    };
+    Q_DECLARE_FLAGS(Rotations, Rotation)
+
+    uint32_t id = 0;
+    Type type = OverlayPlane;
+
+    int possibleCrtcs = 0;
+
+    QVector<uint32_t> supportedFormats;
+
+    Rotations initialRotation = Rotation0;
+    Rotations availableRotations = Rotation0;
+    uint32_t rotationPropertyId = 0;
+};
+
+Q_DECLARE_OPERATORS_FOR_FLAGS(QKmsPlane::Rotations)
+
 struct QKmsOutput
 {
     QString name;
@@ -119,6 +190,7 @@ struct QKmsOutput
     bool forced_plane_set = false;
     uint32_t drm_format = DRM_FORMAT_XRGB8888;
     QString clone_source;
+    QVector<QKmsPlane> available_planes;
 
     void restoreMode(QKmsDevice *device);
     void cleanup(QKmsDevice *device);
@@ -168,6 +240,9 @@ protected:
                                               ScreenInfo *vinfo);
     drmModePropertyPtr connectorProperty(drmModeConnectorPtr connector, const QByteArray &name);
     drmModePropertyBlobPtr connectorPropertyBlob(drmModeConnectorPtr connector, const QByteArray &name);
+    typedef std::function<void(drmModePropertyPtr, quint64)> PropCallback;
+    void enumerateProperties(drmModeObjectPropertiesPtr objProps, PropCallback callback);
+    void discoverPlanes();
 
     QKmsScreenConfig *m_screenConfig;
     QString m_path;
@@ -175,6 +250,8 @@ protected:
 
     quint32 m_crtc_allocator;
 
+    QVector<QKmsPlane> m_planes;
+
 private:
     Q_DISABLE_COPY(QKmsDevice)
 };