backends/drm: Add a check for ranged properties

Include a warning if we are ever setting an invalid value, this can save
some of us quite some time in the future, since failing to fall in the
range makes the whole pipeline become rejected.

src/backends/drm/drm_commit.cpp

@@ -44,6 +44,7 @@ DrmAtomicCommit::DrmAtomicCommit(const QList<DrmPipeline *> &pipelines)
 
 void DrmAtomicCommit::addProperty(const DrmProperty &prop, uint64_t value)
 {
+    prop.checkValueInRange(value);
     m_properties[prop.drmObject()->id()][prop.propId()] = value;
 }
 

src/backends/drm/drm_property.cpp

@@ -42,9 +42,7 @@ void DrmProperty::update(DrmPropertyList &propertyList)
         const auto &[prop, value] = *opt;
         m_propId = prop->prop_id;
         m_current = value;
-        m_immutable = prop->flags & DRM_MODE_PROP_IMMUTABLE;
+        m_flags = prop->flags;
-        m_isBlob = prop->flags & DRM_MODE_PROP_BLOB;
-        m_isBitmask = prop->flags & DRM_MODE_PROP_BITMASK;
         if (prop->flags & DRM_MODE_PROP_RANGE) {
             Q_ASSERT(prop->count_values > 1);
             m_minValue = prop->values[0];
@@ -58,7 +56,7 @@ void DrmProperty::update(DrmPropertyList &propertyList)
                 struct drm_mode_property_enum *en = &prop->enums[i];
                 int j = m_enumNames.indexOf(QByteArray(en->name));
                 if (j >= 0) {
-                    if (m_isBitmask) {
+                    if (m_flags & DRM_MODE_PROP_BITMASK) {
                         m_enumToPropertyMap[1 << j] = 1 << en->value;
                         m_propertyToEnumMap[1 << en->value] = 1 << j;
                     } else {
@@ -68,7 +66,7 @@ void DrmProperty::update(DrmPropertyList &propertyList)
                 }
             }
         }
-        if (m_immutable && m_isBlob) {
+        if ((m_flags & DRM_MODE_PROP_IMMUTABLE) && (m_flags & DRM_MODE_PROP_BLOB)) {
             if (m_current != 0) {
                 m_immutableBlob.reset(drmModeGetPropertyBlob(m_obj->gpu()->fd(), m_current));
                 if (m_immutableBlob && (!m_immutableBlob->data || !m_immutableBlob->length)) {
@@ -108,12 +106,17 @@ const QByteArray &DrmProperty::name() const
 
 bool DrmProperty::isImmutable() const
 {
-    return m_immutable;
+    return m_flags & DRM_MODE_PROP_IMMUTABLE;
 }
 
 bool DrmProperty::isBitmask() const
 {
-    return m_isBitmask;
+    return m_flags & DRM_MODE_PROP_BITMASK;
+}
+
+uint64_t DrmProperty::maxValue() const
+{
+    return m_maxValue;
 }
 
 uint64_t DrmProperty::minValue() const
@@ -121,9 +124,14 @@ uint64_t DrmProperty::minValue() const
     return m_minValue;
 }
 
-uint64_t DrmProperty::maxValue() const
+void DrmProperty::checkValueInRange(uint64_t value) const
 {
-    return m_maxValue;
+    if (Q_UNLIKELY(m_flags & DRM_MODE_PROP_RANGE && (value > m_maxValue || value < m_minValue))) {
+        qCWarning(KWIN_DRM) << "Range property value out of bounds." << m_propName << " value:" << value << "min:" << m_minValue << "max:" << m_maxValue;
+    }
+    if (Q_UNLIKELY(m_flags & DRM_MODE_PROP_SIGNED_RANGE && (int64_t(value) > int64_t(m_maxValue) || int64_t(value) < int64_t(m_minValue)))) {
+        qCWarning(KWIN_DRM) << "Signed range property value out of bounds." << m_propName << " value:" << int64_t(value) << "min:" << int64_t(m_minValue) << "max:" << int64_t(m_maxValue);
+    }
 }
 
 drmModePropertyBlobRes *DrmProperty::immutableBlob() const

src/backends/drm/drm_property.h

@@ -42,6 +42,11 @@ public:
     uint64_t maxValue() const;
     bool isValid() const;
 
+    /**
+     * Prints a warning and returns false if @p value is unacceptable for the property
+     */
+    void checkValueInRange(uint64_t value) const;
+
     void update(DrmPropertyList &propertyList);
     bool setPropertyLegacy(uint64_t value);
 
@@ -60,9 +65,7 @@ protected:
 
     QMap<uint64_t, uint64_t> m_enumToPropertyMap;
     QMap<uint64_t, uint64_t> m_propertyToEnumMap;
-    bool m_immutable = false;
+    uint32_t m_flags;
-    bool m_isBlob = false;
-    bool m_isBitmask = false;
 };
 
 template<typename Enum>
@@ -82,7 +85,7 @@ public:
     bool hasEnum(Enum value) const
     {
         const uint64_t integerValue = static_cast<uint64_t>(value);
-        if (m_isBitmask) {
+        if (isBitmask()) {
             for (uint64_t mask = 1; integerValue >= mask && mask != 0; mask <<= 1) {
                 if ((integerValue & mask) && !m_enumToPropertyMap.contains(mask)) {
                     return false;
@@ -96,7 +99,7 @@ public:
 
     Enum enumForValue(uint64_t value) const
     {
-        if (m_isBitmask) {
+        if (isBitmask()) {
             uint64_t ret = 0;
             for (uint64_t mask = 1; value >= mask && mask != 0; mask <<= 1) {
                 if (value & mask) {
@@ -112,7 +115,7 @@ public:
     uint64_t valueForEnum(Enum enumValue) const
     {
         const uint64_t integer = static_cast<uint64_t>(enumValue);
-        if (m_isBitmask) {
+        if (isBitmask()) {
             uint64_t set = 0;
             for (uint64_t mask = 1; integer >= mask && mask != 0; mask <<= 1) {
                 if (integer & mask) {