xcb: Decode EDID blob

Retrieve and parse EDID blob.
Return screen product information from EDID.

[ChangeLog][Platform Specific Changes][Linux/XCB] Add screen product
information from EDID.

Change-Id: Ic54429cdc90c41342c37511bcaebce95c175f517
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

src/plugins/platforms/xcb/qxcbscreen.cpp

@@ -428,6 +428,18 @@ QXcbScreen::QXcbScreen(QXcbConnection *connection, QXcbVirtualDesktop *virtualDe
         m_sizeMillimeters = m_virtualSizeMillimeters;
 
     m_cursor = new QXcbCursor(connection, this);
+
+    // Parse EDID
+    if (m_edid.parse(getEdid()))
+        qCDebug(lcQpaScreen, "EDID data for output \"%s\": identifier '%s', manufacturer '%s', model '%s', serial '%s', physical size: %.2fx%.2f",
+                name().toLatin1().constData(),
+                m_edid.identifier.toLatin1().constData(),
+                m_edid.manufacturer.toLatin1().constData(),
+                m_edid.model.toLatin1().constData(),
+                m_edid.serialNumber.toLatin1().constData(),
+                m_edid.physicalSize.width(), m_edid.physicalSize.height());
+    else
+        qCWarning(lcQpaScreen) << "Failed to parse EDID data for output" << name();
 }
 
 QXcbScreen::~QXcbScreen()
@@ -452,6 +464,21 @@ QString QXcbScreen::getOutputName(xcb_randr_get_output_info_reply_t *outputInfo)
     return name;
 }
 
+QString QXcbScreen::manufacturer() const
+{
+    return m_edid.manufacturer;
+}
+
+QString QXcbScreen::model() const
+{
+    return m_edid.model;
+}
+
+QString QXcbScreen::serialNumber() const
+{
+    return m_edid.serialNumber;
+}
+
 QWindow *QXcbScreen::topLevelAt(const QPoint &p) const
 {
     xcb_window_t root = screen()->root;
@@ -830,6 +857,41 @@ QXcbXSettings *QXcbScreen::xSettings() const
     return m_virtualDesktop->xSettings();
 }
 
+QByteArray QXcbScreen::getOutputProperty(xcb_atom_t atom) const
+{
+    QByteArray result;
+
+    auto cookie =
+        xcb_randr_get_output_property(xcb_connection(), m_output,
+                                      atom, XCB_ATOM_ANY, 0, 100, false, false);
+    auto reply = xcb_randr_get_output_property_reply(xcb_connection(), cookie, nullptr);
+    if (reply->type == XCB_ATOM_INTEGER && reply->format == 8) {
+        quint8 *data = new quint8[reply->num_items];
+        memcpy(data, xcb_randr_get_output_property_data(reply), reply->num_items);
+        result = QByteArray(reinterpret_cast<const char *>(data), reply->num_items);
+        delete[] data;
+    }
+    free(reply);
+
+    return result;
+}
+
+QByteArray QXcbScreen::getEdid() const
+{
+    // Try a bunch of atoms
+    xcb_atom_t atom = connection()->internAtom("EDID");
+    QByteArray result = getOutputProperty(atom);
+    if (result.isEmpty()) {
+        atom = connection()->internAtom("EDID_DATA");
+        result = getOutputProperty(atom);
+    }
+    if (result.isEmpty()) {
+        atom = connection()->internAtom("XFree86_DDC_EDID1_RAWDATA");
+        result = getOutputProperty(atom);
+    }
+    return result;
+}
+
 static inline void formatRect(QDebug &debug, const QRect r)
 {
     debug << r.width() << 'x' << r.height()

src/plugins/platforms/xcb/qxcbscreen.h

@@ -53,6 +53,8 @@
 
 #include <private/qfontengine_p.h>
 
+#include <QtEdidSupport/private/qedidparser_p.h>
+
 QT_BEGIN_NAMESPACE
 
 class QXcbConnection;
@@ -147,6 +149,10 @@ public:
 
     QWindow *topLevelAt(const QPoint &point) const override;
 
+    QString manufacturer() const override;
+    QString model() const override;
+    QString serialNumber() const override;
+
     QRect geometry() const override { return m_geometry; }
     QRect availableGeometry() const override {return m_availableGeometry;}
     int depth() const override { return screen()->root_depth; }
@@ -206,6 +212,9 @@ public:
 private:
     void sendStartupMessage(const QByteArray &message) const;
 
+    QByteArray getOutputProperty(xcb_atom_t atom) const;
+    QByteArray getEdid() const;
+
     QXcbVirtualDesktop *m_virtualDesktop;
     xcb_randr_output_t m_output;
     xcb_randr_crtc_t m_crtc;
@@ -224,6 +233,7 @@ private:
     QXcbCursor *m_cursor;
     int m_refreshRate = 60;
     int m_pixelDensity = 1;
+    QEdidParser m_edid;
 };
 
 #ifndef QT_NO_DEBUG_STREAM

src/plugins/platforms/xcb/xcb_qpa_lib.pro

@@ -5,7 +5,8 @@ DEFINES += QT_NO_FOREACH
 QT += \
     core-private gui-private \
     service_support-private theme_support-private \
-    eventdispatcher_support-private fontdatabase_support-private
+    eventdispatcher_support-private fontdatabase_support-private \
+    edid_support-private
 
 qtHaveModule(linuxaccessibility_support-private): \
     QT += linuxaccessibility_support-private