solid: implement getter for the minimum CPU speed

cannot test it for the devinfo backend right now so it is on the TODO, for
the udev backend it ends up as being optimization because the check if the
frequency can be changed already reads cpuinfo_min_freq and
cpuinfo_max_freq files

Signed-off-by: Ivailo Monev <xakepa10@gmail.com>

solid/solid/backends/devinfo/devinfoprocessor.cpp

@@ -42,6 +42,12 @@ int Processor::number() const
     return m_device->deviceProperty(DevinfoDevice::DeviceName).right(1).toInt();
 }
 
+int Processor::minSpeed() const
+{
+#warning implement
+    return 0;
+}
+
 int Processor::maxSpeed() const
 {
     int result = 0;

solid/solid/backends/devinfo/devinfoprocessor.h

@@ -42,6 +42,7 @@ public:
     virtual ~Processor();
 
     virtual int number() const;
+    virtual int minSpeed() const;
     virtual int maxSpeed() const;
     virtual bool canChangeFrequency() const;
     virtual Solid::Processor::InstructionSets instructionSets() const;

solid/solid/backends/fakehw/fakecomputer.xml

@@ -90,6 +90,7 @@
             <property key="vendor">Acme Corporation</property>
             <property key="parent">/org/kde/solid/fakehw/computer</property>
             <property key="number">0</property>
+            <property key="minSpeed">1600</property>
             <property key="maxSpeed">3200</property>
             <property key="canChangeFrequency">true</property>
             <property key="instructionSets">mmx,sse</property>
@@ -100,6 +101,7 @@
             <property key="vendor">Acme Corporation</property>
             <property key="parent">/org/kde/solid/fakehw/computer</property>
             <property key="number">1</property>
+            <property key="minSpeed">1600</property>
             <property key="maxSpeed">3200</property>
             <property key="canChangeFrequency">true</property>
         </device>

solid/solid/backends/fakehw/fakeprocessor.cpp

@@ -38,6 +38,11 @@ int FakeProcessor::number() const
     return fakeDevice()->property("number").toInt();
 }
 
+int FakeProcessor::minSpeed() const
+{
+    return fakeDevice()->property("minSpeed").toInt();
+}
+
 int FakeProcessor::maxSpeed() const
 {
     return fakeDevice()->property("maxSpeed").toInt();

solid/solid/backends/fakehw/fakeprocessor.h

@@ -41,6 +41,7 @@ public:
 
 public Q_SLOTS:
     virtual int number() const;
+    virtual int minSpeed() const;
     virtual int maxSpeed() const;
     virtual bool canChangeFrequency() const;
     virtual Solid::Processor::InstructionSets instructionSets() const;

solid/solid/backends/udev/udevprocessor.cpp

@@ -22,14 +22,15 @@
 #include "udevdevice.h"
 #include "cpuinfo.h"
 
-#include <QtCore/QFile>
-#include <QtCore/QDir>
+#include <QFile>
+#include <QDir>
+#include <qmath.h>
 
 using namespace Solid::Backends::UDev;
 
 Processor::Processor(UDevDevice *device)
     : DeviceInterface(device),
-      m_canChangeFrequency(NotChecked),
+    m_minSpeed(-1),
     m_maxSpeed(-1)
 {
 }
@@ -48,43 +49,25 @@ int Processor::number() const
 }
 
 // NOTE: do not parse /proc/cpuinfo for "cpu MHz", that may be current not maximum speed
+int Processor::minSpeed() const
+{
+    if (m_minSpeed == -1) {
+        m_minSpeed = getCPUInfo("/cpufreq/cpuinfo_min_freq");
+    }
+    return m_minSpeed;
+}
+
 int Processor::maxSpeed() const
 {
     if (m_maxSpeed == -1) {
-        QFile cpuMaxFreqFile(m_device->deviceName() + prefix() + "/cpufreq/cpuinfo_max_freq");
-        if (cpuMaxFreqFile.open(QIODevice::ReadOnly)) {
-            qlonglong maxFreq = cpuMaxFreqFile.readAll().trimmed().toLongLong();
-            if (maxFreq > 0) {
-                // cpuinfo_max_freq is in kHz
-                m_maxSpeed = static_cast<int>(maxFreq / 1000);
-            } else {
-                m_maxSpeed = 0;
-            }
-        }
+        m_maxSpeed = getCPUInfo("/cpufreq/cpuinfo_max_freq");
     }
     return m_maxSpeed;
 }
 
 bool Processor::canChangeFrequency() const
 {
-    if (m_canChangeFrequency == NotChecked) {
-        /* Note that cpufreq is the right information source here, rather than
-         * anything to do with throttling (ACPI T-states).  */
-
-        m_canChangeFrequency = CannotChangeFreq;
-
-        QFile cpuMinFreqFile(m_device->deviceName() + prefix() + "/cpufreq/cpuinfo_min_freq");
-        QFile cpuMaxFreqFile(m_device->deviceName() + prefix() + "/cpufreq/cpuinfo_max_freq");
-        if (cpuMinFreqFile.open(QIODevice::ReadOnly) && cpuMaxFreqFile.open(QIODevice::ReadOnly)) {
-            qlonglong minFreq = cpuMinFreqFile.readAll().trimmed().toLongLong();
-            qlonglong maxFreq = cpuMaxFreqFile.readAll().trimmed().toLongLong();
-            if (minFreq > 0 && maxFreq > minFreq) {
-                m_canChangeFrequency = CanChangeFreq;
-            }
-        }
-    }
-
-    return m_canChangeFrequency == CanChangeFreq;
+    return (minSpeed() > 0 && maxSpeed() > 0);
 }
 
 Solid::Processor::InstructionSets Processor::instructionSets() const
@@ -120,14 +103,25 @@ Solid::Processor::InstructionSets Processor::instructionSets() const
     return cpuinstructions;
 }
 
-QString Processor::prefix() const
+int Processor::getCPUInfo(const char* filename) const
 {
-    const QLatin1String sysPrefix("/sysdev");
-    if (QDir(m_device->deviceName() + sysPrefix).exists()) {
-        return sysPrefix;
-    }
+    static const QLatin1String sysPrefix("/sysdev");
 
-    return QString();
+    QString cpuFreqFileName(m_device->deviceName());
+    if (QDir(cpuFreqFileName + sysPrefix).exists()) {
+        cpuFreqFileName.append(sysPrefix);
+    }
+    cpuFreqFileName.append(QLatin1String(filename));
+
+    QFile cpuFreqFile(cpuFreqFileName);
+    if (cpuFreqFile.open(QIODevice::ReadOnly)) {
+        const qlonglong value = cpuFreqFile.readAll().trimmed().toLongLong();
+        if (value > 0) {
+            // value is in kHz
+            return qRound(value / 1000);
+        }
+    }
+    return 0;
 }
 
 #include "backends/udev/moc_udevprocessor.cpp"

solid/solid/backends/udev/udevprocessor.h

@@ -42,19 +42,15 @@ public:
     virtual ~Processor();
 
     virtual int number() const;
+    virtual int minSpeed() const;
     virtual int maxSpeed() const;
     virtual bool canChangeFrequency() const;
     virtual Solid::Processor::InstructionSets instructionSets() const;
 
 private:
-    enum CanChangeFrequencyEnum {
-        NotChecked,
-        CanChangeFreq,
-        CannotChangeFreq
-    };
-    mutable CanChangeFrequencyEnum m_canChangeFrequency;
+    mutable int m_minSpeed;
     mutable int m_maxSpeed;
-    QString prefix() const;
+    int getCPUInfo(const char* filename) const;
 };
 }
 }

solid/solid/ifaces/processor.h

@@ -46,6 +46,13 @@ namespace Ifaces
          */
         virtual int number() const = 0;
 
+        /**
+         * Retrieves the minimum speed of the processor.
+         *
+         * @return the minimum speed in MHz
+         */
+        virtual int minSpeed() const = 0;
+
         /**
          * Retrieves the maximum speed of the processor.
          *

solid/solid/processor.cpp

@@ -41,6 +41,12 @@ int Solid::Processor::number() const
     return_SOLID_CALL(Ifaces::Processor *, d->backendObject(), 0, number());
 }
 
+int Solid::Processor::minSpeed() const
+{
+    Q_D(const Processor);
+    return_SOLID_CALL(Ifaces::Processor *, d->backendObject(), 0, minSpeed());
+}
+
 int Solid::Processor::maxSpeed() const
 {
     Q_D(const Processor);

solid/solid/processor.h

@@ -39,6 +39,7 @@ namespace Solid
         Q_ENUMS(InstructionSet)
         Q_FLAGS(InstructionSets)
         Q_PROPERTY(int number READ number)
+        Q_PROPERTY(qulonglong minSpeed READ minSpeed)
         Q_PROPERTY(qulonglong maxSpeed READ maxSpeed)
         Q_PROPERTY(bool canChangeFrequency READ canChangeFrequency)
         Q_PROPERTY(InstructionSets instructionSets READ instructionSets)
@@ -98,6 +99,14 @@ namespace Solid
          */
         int number() const;
 
+        /**
+         * Retrieves the minimum speed of the processor.
+         *
+         * @return the minimum speed in MHz, or 0 if the device can't be queried for this
+         * information.
+         */
+        int minSpeed() const;
+
         /**
          * Retrieves the maximum speed of the processor.
          *

solid/tests/fakehardwaretest.cpp

@@ -61,6 +61,7 @@ void FakeHardwareTest::testFakeBackend()
 
     QCOMPARE(processor->number(), 0);
     QCOMPARE(processor->canChangeFrequency(), true);
+    QCOMPARE((int)processor->minSpeed(), 1600);
     QCOMPARE((int)processor->maxSpeed(), 3200);
 
     Solid::Processor::InstructionSets instructionsets;