Parse EDID for missing modes (ultrawide issue)

For some reason X ignores ultrawide resolutions in the EDID data...
Additionally (at least on LG models) the EDID data wrongly says 1080p
would be the preferred resolution of the screen, so we now take the
physical dimensions of the screen into account and override that
decision, if applicable. This assumes square pixels, but that shouldn't
be too crazy of an assumption.

4 files changed, 193 insertions, 47 deletions

diff --git a/src/xprivate.cpp b/src/xprivate.cpp
index 7667b9e..4be7098 100644
--- a/src/xprivate.cpp
+++ b/src/xprivate.cpp
@@ -37,6 +37,21 @@ static bool xRectLessThan(const OutputInfo* const &a, const OutputInfo* const &b
         return a->crtc->x < b->crtc->x;
 }
 
+static int modeEqual(const XRRModeInfo *a, const XRRModeInfo *b)
+{
+	return (a->width == b->width &&
+		a->height == b->height &&
+		a->dotClock / 10 == b->dotClock / 10 &&
+		a->hSyncStart == b->hSyncStart &&
+		a->hSyncEnd == b->hSyncEnd &&
+		a->hTotal == b->hTotal &&
+		a->hSkew == b->hSkew &&
+		a->vSyncStart == b->vSyncStart &&
+		a->vSyncEnd == b->vSyncEnd &&
+		a->vTotal == b->vTotal &&
+		a->modeFlags == b->modeFlags);
+}
+
 /*
  * Class members
  */
@@ -224,51 +239,172 @@ void XPrivate::updateScreenResources()
     qDebug() << "Loaded.";
 }
 
+void XPrivate::addMissingEdidResolutions()
+{
+	XRRScreenResources *resptr = XRRGetScreenResourcesCurrent(_display, DefaultRootWindow(_display));
+	for (int i = 0; i < resptr->noutput; ++i) {
+		unsigned char prop[512];
+		unsigned long edidLen = 512;
+		if (!getEdid(resptr->outputs[i], prop, &edidLen))
+			continue;
+		if (edidLen < 256)
+			continue;
+		for (unsigned int j = 128; j < edidLen - 127; j += 128) {
+			addMissingModesFromEdid(resptr, resptr->outputs[i], prop + j);
+		}
+	}
+	XRRFreeScreenResources(resptr);
+}
+
+bool XPrivate::getEdid(RROutput outputId, unsigned char *buffer, unsigned long *size)
+{
+	int numProps = 0;
+	bool found = false;
+	Atom* properties = XRRListOutputProperties(_display, outputId, &numProps);
+	for (int i = 0; i < numProps; ++i) {
+		if (properties[i] == _EDID_ATOM) {
+			found = true;
+			break;
+		}
+	}
+	XFree(properties);
+	if (!found)
+		return false;
+
+	unsigned long nitems, bytes_after;
+	unsigned char *prop = nullptr;
+	int actual_format;
+	Atom actual_type;
+	bool valid;
+
+	XRRGetOutputProperty(_display, outputId, _EDID_ATOM,
+											 0, long(size), False, False,
+											 AnyPropertyType,
+											 &actual_type, &actual_format,
+											 &nitems, &bytes_after, &prop);
+	valid = (actual_format == 8 && nitems >= 128 && prop != nullptr);
+	if (valid) {
+		memcpy(buffer, prop, qMin(*size, nitems));
+		*size = qMin(nitems, *size);
+	} else {
+		*size = 0;
+	}
+	if (prop != nullptr) {
+		XFree(prop);
+	}
+	return valid;
+}
+
 bool XPrivate::readEdid(OutputInfo* output)
 {
-        int numProps = 0;
-        bool found = false;
-        Atom* properties = XRRListOutputProperties(_display, output->id, &numProps);
-        for (int i = 0; i < numProps; ++i) {
-                if (properties[i] == _EDID_ATOM) {
-                        found = true;
-                        break;
-                }
-        }
-        XFree(properties);
-        if (!found)
-                return false;
-
-        unsigned long nitems, bytes_after;
-        unsigned char *prop;
-        int actual_format;
-        Atom actual_type;
-        bool valid;
-
-        XRRGetOutputProperty(_display, output->id, _EDID_ATOM,
-                                                 0, 128, False, False,
-                                                 AnyPropertyType,
-                                                 &actual_type, &actual_format,
-                                                 &nitems, &bytes_after, &prop);
-        valid = (actual_format == 8 && nitems >= 128);
-
-        if (valid) {
-                int idx;
-                for (unsigned char *byte = prop + 54; byte < prop + 126; byte += 18) {
-                        if (byte[0] != 0 || byte[1] != 0 || byte[2] != 0)
-                                continue; // Not a text block
-                        if (byte[3] == 0xfc) { // Serial number
-                                output->modelName = QString::fromLatin1(reinterpret_cast<const char*>(byte) + 5, 13); // It's actually CP-437 but meh
-                                if ((idx = output->modelName.indexOf('\r')) != -1) {
-                                        output->modelName.truncate(idx);
-                                }
-                                output->modelName = output->modelName.trimmed();
-                                qDebug() << "Display name:" << output->modelName;
-                        }
-                }
-        }
-        XFree(prop);
-        return valid;
+		unsigned char prop[512];
+		unsigned long edidLen = 512;
+
+		if (!getEdid(output->id, prop, &edidLen))
+			return false;
+
+		int idx;
+		for (unsigned char *byte = prop + 54; byte < prop + 126; byte += 18) {
+			if (byte[0] != 0 || byte[1] != 0 || byte[2] != 0)
+				continue; // Not a text block
+			if (byte[3] == 0xfc) { // Serial number
+				output->modelName = QString::fromLatin1(reinterpret_cast<const char*>(byte) + 5, 13); // It's actually CP-437 but meh
+				if ((idx = output->modelName.indexOf('\r')) != -1) {
+					output->modelName.truncate(idx);
+				}
+				output->modelName = output->modelName.trimmed();
+				qDebug() << "Display name:" << output->modelName;
+			}
+		}
+		return true;
+}
+
+void XPrivate::addMissingModesFromEdid(XRRScreenResources *res, RROutput outputId, unsigned char *data)
+{
+	if (data[0] != 2) // Not type 2, skip
+		return;
+	if (data[2] == 0) // Empty block
+		return;
+	int dtdOffset = data[2];
+	if (dtdOffset < 4) // No DTD blocks
+		return;
+	if (dtdOffset > 128) {
+		dtdOffset = 128;
+	}
+
+	int hactive, vactive, pixclk, hsyncoff, hsyncwidth, hblank, vsyncoff, vsyncwidth, vblank;
+	for (int i = dtdOffset; i < 128 - 17; i += 18) {
+		if (data[i] == 0 && data[i + 1] == 0)
+			continue;
+		hactive = data[i+2] + ((data[i+4] & 0xf0) << 4);
+		hblank = data[i+3] + ((data[i+4] & 0x0f) << 8);
+		vactive = data[i+5] + ((data[i+7] & 0xf0) << 4);
+		vblank = data[i+6] + ((data[i+7] & 0x0f) << 8);
+		pixclk = (data[i+1] << 8) | (data[i]); // 10kHz
+		hsyncoff = data[i+8] | ((data[i+11] & 0xC0) << 2);
+		hsyncwidth = data[i+9] | ((data[i+11] & 0x30) << 4);
+		vsyncoff = ((data[i+10] & 0xf0) >> 4) | ((data[i+11] & 0x0C) << 2);
+		vsyncwidth = (data[i+10] & 0x0f) | ((data[i+11] & 0x03) << 4);
+		char buf[100];
+		XRRModeInfo m;
+		memset(&m, 0, sizeof(m));
+		m.width     = static_cast<unsigned int>(hactive);
+		m.height    = static_cast<unsigned int>(vactive);
+		m.dotClock  = static_cast<unsigned long>(pixclk) * 10ul * 1000ul;
+		m.hSyncStart= static_cast<unsigned int>(hactive + hsyncoff);
+		m.hSyncEnd  = static_cast<unsigned int>(hactive + hsyncoff + hsyncwidth);
+		m.hTotal    = static_cast<unsigned int>(hactive + hblank);
+		m.hSkew     = 0;
+		m.vSyncStart= static_cast<unsigned int>(vactive + vsyncoff);
+		m.vSyncEnd  = static_cast<unsigned int>(vactive + vsyncoff + vsyncwidth);
+		m.vTotal    = static_cast<unsigned int>(vactive + vblank);
+		m.id        = 0;
+		m.name = buf;
+		m.nameLength = static_cast<unsigned int>(snprintf(buf, sizeof(buf), "%dx%d_%d", hactive, vactive, static_cast<int>(m.dotClock / (m.hTotal * m.vTotal))));
+		if (m.nameLength > sizeof(buf)) {
+			m.nameLength = sizeof(buf);
+		}
+		if ((data[i+17] & 0x18) == 0x18) {
+			// Digital Separate
+			if (data[i+17] & 0x04) {
+				m.modeFlags |= RR_VSyncPositive;
+			} else {
+				m.modeFlags |= RR_VSyncNegative;
+			}
+			if (data[i+17] & 0x02) {
+				m.modeFlags |= RR_HSyncPositive;
+			} else {
+				m.modeFlags |= RR_HSyncNegative;
+			}
+		} else if ((data[i+17] & 0x18) == 0x10) {
+			// Digital Composite
+			if (data[i+17] & 0x02) {
+				m.modeFlags |= RR_HSyncPositive;
+			} else {
+				m.modeFlags |= RR_HSyncNegative;
+			}
+			m.modeFlags |= RR_VSyncNegative; // Default? Clarify...
+		} else {
+			m.modeFlags |= RR_VSyncNegative | RR_HSyncNegative; // ...
+		}
+		if (data[i+17] & 0x80) {
+			m.modeFlags |= RR_Interlace;
+		}
+		// See if we should add this mode
+		RRMode modeId = 0;
+		for (int mode = 0; mode < res->nmode; ++mode) {
+			if (modeEqual(&res->modes[mode], &m)) {
+				modeId = res->modes[mode].id;
+				break;
+			}
+		}
+		if (modeId == 0) {
+			modeId = XRRCreateMode(_display, DefaultRootWindow(_display), &m);
+		}
+		if (modeId != 0) {
+			XRRAddOutputMode(_display, outputId, modeId);
+		}
+	}
 }
 
 void XPrivate::setScreenSize(const QSize &size)
diff --git a/src/xprivate.h b/src/xprivate.h
index d3e9129..28234ac 100644
--- a/src/xprivate.h
+++ b/src/xprivate.h
@@ -44,7 +44,10 @@ public:
 
     void         freeResources();
     void         updateScreenResources();
-    bool         readEdid(OutputInfo* output);
+	void         addMissingEdidResolutions();
+	bool         getEdid(RROutput outputId, unsigned char *buffer, unsigned long *size);
+	bool         readEdid(OutputInfo* output);
+	void         addMissingModesFromEdid(XRRScreenResources *res, RROutput outputId, unsigned char *data);
     void         disconnectAllCrtcs();
     XRRModeInfo* getPreferredMode(OutputInfo *oi, XRRModeInfo *fallback = nullptr) const;
     void         setScreenSize(const QSize &size);
diff --git a/src/xx.cpp b/src/xx.cpp
index d0b6a3d..80cb1b1 100644
--- a/src/xx.cpp
+++ b/src/xx.cpp
@@ -225,6 +225,11 @@ static double toVertRefresh(const XRRModeInfo *mode)
 	return 0;
 }
 
+void ScreenSetup::addMissingEdidResolutions()
+{
+	a->addMissingEdidResolutions();
+}
+
 //___________________________________________________________________________
 void ScreenSetup::updateScreenResources()
 {
@@ -254,10 +259,11 @@ void ScreenSetup::initModes()
 	for (XRRModeInfo *mode : a->_modeMap) {
 		if (toVertRefresh(mode) < 58 || toVertRefresh(mode) > 61)
 			continue; // Play it safe and consider only those for copying that are 60Hz
-		wanted.remove(RES(mode->width, mode->height));
+		if (!wanted.remove(RES(mode->width, mode->height)))
+			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))
+			if (a->getOutputModeForResolution(info->output, mode->width, mode->height) != None)
 				continue;
 			XRRAddOutputMode(a->_display, info->id, mode->id);
 		}
@@ -269,7 +275,7 @@ void ScreenSetup::initModes()
 		unsigned int y = res >> 16;
 		createMode(x, y, 60, QString::asprintf("%ux%u", x, y));
 	}
-	if (!wanted.isEmpty()) {
+	if (!wanted.isEmpty()) { // Modes were added, update for final loop below
 		updateScreenResources();
 	}
 	// Finally copy all those the projector supports to other outputs
diff --git a/src/xx.h b/src/xx.h
index de52db3..7346c4a 100644
--- a/src/xx.h
+++ b/src/xx.h
@@ -61,6 +61,7 @@ class ScreenSetup : public QObject
 {
 	Q_OBJECT
 public:
+	void         addMissingEdidResolutions();
 	void         updateScreenResources();
 	void         initModes();
 	ScreenMode   getCurrentMode();