Try all possible modes for a given resolution

3 files changed, 72 insertions, 35 deletions

diff --git a/src/xprivate.cpp b/src/xprivate.cpp
index 62a4895..1273e1e 100644
--- a/src/xprivate.cpp
+++ b/src/xprivate.cpp
@@ -3,6 +3,13 @@
 #include <QDebug>
 #include <QRegularExpression>
 
+static double toVertRefresh(const XRRModeInfo *mode)
+{
+    if (mode->hTotal > 0 && mode->vTotal > 0)
+        return (double(mode->dotClock) /	(double(mode->hTotal) * double(mode->vTotal)));
+    return 0;
+}
+
 /**
  * Check list of known model names that falsely report a screen size or similar
  */
@@ -52,6 +59,14 @@ static int modeEqual(const XRRModeInfo *a, const XRRModeInfo *b)
 		a->modeFlags == b->modeFlags);
 }
 
+static int errorHandler(Display *dpy, XErrorEvent *err)
+{
+    char buf[1000];
+    XGetErrorText(dpy, err->error_code, buf, 1000);
+    qDebug() << "**X11 error**" << buf;
+    return 0;
+}
+
 /*
  * Class members
  */
@@ -65,6 +80,7 @@ XPrivate::XPrivate()
             qFatal("Cannot open display");
             ::exit(1);
     }
+    XSetErrorHandler(errorHandler);
     _EDID_ATOM = XInternAtom(_display, RR_PROPERTY_RANDR_EDID, False);
 }
 
@@ -452,7 +468,7 @@ void XPrivate::copyModesToAll(RROutput sourceId, int num)
                         if (other == sourceId)
                                 continue;
                         const XRROutputInfo *otherInfo = _outputMap[other]->output;
-                        if (getOutputModeForResolution(otherInfo, mode->width, mode->height) != None)
+                        if (!getOutputModeForResolution(otherInfo, mode->width, mode->height).isEmpty())
                                 continue;
                         XRRAddOutputMode(_display, other, outputInfo->modes[i]);
                 }
@@ -460,32 +476,42 @@ void XPrivate::copyModesToAll(RROutput sourceId, int num)
 }
 
 /**
- * Get the RRMode for the specified output matching the given resolution.
+ * Get all known modes matching the given resolution.
  * If multiple modes match the given resolution, the function will
- * return the first matching preferred mode. If no preferred
- * mode matches, the non-preferred mode with the highest refresh rate
- * will be returned.
- * Otherwise, None will be returned.
+ * put the preferred resolution first, then all others sorted by
+ * dotClock, descending.
  */
-RRMode XPrivate::getOutputModeForResolution(const XRROutputInfo *output, unsigned int width, unsigned int height) const
+QList<RRMode> XPrivate::getOutputModeForResolution(const XRROutputInfo *output, unsigned int width, unsigned int height) const
 {
-        XRRModeInfo *retval = nullptr;
+        XRRModeInfo *pref = nullptr;
+        QList<XRRModeInfo*> others;
         for (int i = 0; i < output->nmode; ++i) {
-                if (!_modeMap.contains(output->modes[i]))
-                        continue;
-                XRRModeInfo *info = _modeMap[output->modes[i]];
-                if (info->width == width && info->height == height) {
-                        if (i < output->npreferred)
-                                return output->modes[i];
-                        if (retval == nullptr || retval->dotClock < info->dotClock) {
-                                retval = info;
-                        }
+            if (!_modeMap.contains(output->modes[i]))
+                continue;
+            XRRModeInfo *info = _modeMap[output->modes[i]];
+            if (info->width == width && info->height == height) {
+                if (i < output->npreferred && pref == nullptr) {
+                    pref = info;
+                } else {
+                    others.append(info);
                 }
+            }
+        }
+        // Sort others descending by dotClock
+        qSort(others.begin(), others.end(), [](const XRRModeInfo *a, const XRRModeInfo *b) {
+            return toVertRefresh(a) > toVertRefresh(b);
+        });
+        QList<RRMode> ret;
+        if (pref != nullptr) {
+            ret.append(pref->id);
+        }
+        for (auto e : others) {
+            ret.append(e->id);
         }
-        return retval == nullptr ? None : retval->id;
+        return ret;
 }
 
-RRMode XPrivate::getOutputModeForResolution(const XRROutputInfo *output, const QSize &resolution) const
+QList<RRMode> XPrivate::getOutputModeForResolution(const XRROutputInfo *output, const QSize &resolution) const
 {
         return getOutputModeForResolution(output, static_cast<unsigned int>(resolution.width()), static_cast<unsigned int>(resolution.height()));
 }
@@ -563,14 +589,20 @@ XRRModeInfo* XPrivate::getPreferredMode(const OutputInfo *oi, XRRModeInfo *fallb
 			if (fallback != nullptr) {
 				maxX = int(fallback->width);
 				maxY = int(fallback->height);
-				mode = getOutputModeForResolution(oi->output, fallback->width, fallback->height);
+                auto list = getOutputModeForResolution(oi->output, fallback->width, fallback->height);
+                if (!list.isEmpty()) {
+                    mode = list.first();
+                }
 			}
 			static const std::vector<QSize> wanted = {QSize(1920, 1080), QSize(1280, 800), QSize(1280, 720), QSize(1152, 864), QSize(1024, 768)};
 			for (const QSize s : wanted) {
 				if (mode != None)
 					break;
 				if (s.width() <= maxX && s.height() <= maxY) {
-					mode = getOutputModeForResolution(oi->output, s.width(), s.height());
+                    auto list = getOutputModeForResolution(oi->output, s.width(), s.height());
+                    if (!list.isEmpty()) {
+                        mode = list.first();
+                    }
 				}
 			}
 			if (mode == None) {
@@ -616,25 +648,30 @@ QList<QSize> XPrivate::getTotalSize(const QList<OutputInfo*> &projectors, const
 
 bool XPrivate::setOutputResolution(OutputInfo *oi, int x, int y, const QSize &size, bool dryRun)
 {
-    RRMode mode = getOutputModeForResolution(oi->output, size);
+    QList<RRMode> modes = getOutputModeForResolution(oi->output, size);
     Status s = RRSetConfigSuccess;
-    if (mode == None) {
+    if (modes.isEmpty()) {
         qDebug() << "Cannot set" << oi->outputName << "to" << size << " since it's not supported";
         if (oi->output->nmode == 0)
             return false;
         qDebug() << "falling back to its default";
-        mode = oi->output->modes[0];
+        modes.append(oi->output->modes[0]);
     }
     if (!dryRun) {
-        s = XRRSetCrtcConfig(_display,
-                             _screenResources,
-                             oi->output->crtc,
-                             CurrentTime,
-                             x, y, mode,
-                             RR_Rotate_0,
-                             &oi->id, 1);
+        for (RRMode mode : modes) {
+            qDebug() << "Trying" << toVertRefresh(_modeMap[mode]) << "Hz";
+            s = XRRSetCrtcConfig(_display,
+                                 _screenResources,
+                                 oi->output->crtc,
+                                 CurrentTime,
+                                 x, y, mode,
+                                 RR_Rotate_0,
+                                 &oi->id, 1);
+            if (s == RRSetConfigSuccess)
+                break;
+        }
     }
-    qDebug() << (s != RRSetConfigSuccess ? "Failed to" : "") << "Set" << oi->outputName << "to" << _modeMap[mode]->width << "x" << _modeMap[mode]->height << "-- offset" << x << "/" << y;
+    qDebug() << (s != RRSetConfigSuccess ? "Failed to" : "") << "Set" << oi->outputName << "to" << size << "-- offset" << x << "/" << y;
     if (s == RRSetConfigSuccess) {
         return true;
     }
diff --git a/src/xprivate.h b/src/xprivate.h
index c7ef29b..2937442 100644
--- a/src/xprivate.h
+++ b/src/xprivate.h
@@ -52,8 +52,8 @@ public:
     void         disconnectAllCrtcs();
 	XRRModeInfo* getPreferredMode(const OutputInfo *oi, XRRModeInfo *fallback = nullptr) const;
     void         setScreenSize(const QSize &size);
-    RRMode       getOutputModeForResolution(const XRROutputInfo *output, unsigned int width, unsigned int height) const;
-    RRMode       getOutputModeForResolution(const XRROutputInfo *output, const QSize &resolution) const;
+    QList<RRMode> getOutputModeForResolution(const XRROutputInfo *output, unsigned int width, unsigned int height) const;
+    QList<RRMode> getOutputModeForResolution(const XRROutputInfo *output, const QSize &resolution) const;
     RRCrtc       getFreeCrtc(const XRROutputInfo* output) const;
     bool         setOutputResolution(OutputInfo *oi, int x, int y, const QSize &size, bool dryRun = false);
     QList<QSize> getTotalSize(const QList<OutputInfo*> &projectors, const QList<OutputInfo*> &screens) const;
diff --git a/src/xx.cpp b/src/xx.cpp
index 0b91161..62bd353 100644
--- a/src/xx.cpp
+++ b/src/xx.cpp
@@ -265,7 +265,7 @@ void ScreenSetup::initModes()
 			continue; // Is not a wanted resolution
 		// Make sure all outputs got it
 		for (OutputInfo *info : a->_outputMap) {
-			if (a->getOutputModeForResolution(info->output, mode->width, mode->height) != None)
+            if (!a->getOutputModeForResolution(info->output, mode->width, mode->height).isEmpty())
 				continue;
 			XRRAddOutputMode(a->_display, info->id, mode->id);
 		}