diff --git a/unix/xserver/hw/vnc/Makefile.am b/unix/xserver/hw/vnc/Makefile.am
index d344c85d5d..caf3b9480c 100644
--- a/unix/xserver/hw/vnc/Makefile.am
+++ b/unix/xserver/hw/vnc/Makefile.am
@@ -12,7 +12,7 @@ AM_CPPFLAGS = \
 	-I$(TIGERVNC_BUILDDIR) \
 	-I$(TIGERVNC_SRCDIR)/common \
 	-I$(TIGERVNC_SRCDIR)/unix/common \
-	$(DIX_CFLAGS)
+	$(DIX_CFLAGS) $(LIBXCVT_CFLAGS)
 
 AM_CXXFLAGS = -std=gnu++11
 
@@ -53,7 +53,11 @@ LOCAL_LIBS = \
 	$(COMMON_LIBS)
 
 Xvnc_DEPENDENCIES = $(LOCAL_LIBS)
-Xvnc_LDADD = $(LOCAL_LIBS) $(XSERVER_SYS_LIBS) $(XVNC_SYS_LIBS)
+Xvnc_LDADD = \
+	$(LOCAL_LIBS) \
+	$(XSERVER_SYS_LIBS) \
+	$(XVNC_SYS_LIBS) \
+	$(LIBXCVT_LIBS)
 
 Xvnc_LDFLAGS = $(LD_EXPORT_SYMBOLS_FLAG)
 
diff --git a/unix/xserver/hw/vnc/xvnc.c b/unix/xserver/hw/vnc/xvnc.c
index 092b99b10f..0165d59897 100644
--- a/unix/xserver/hw/vnc/xvnc.c
+++ b/unix/xserver/hw/vnc/xvnc.c
@@ -41,6 +41,9 @@ from the X Consortium.
 #include "xorg-version.h"
 
 #include <stdio.h>
+#ifdef HAVE_LIBXCVT
+#include <libxcvt/libxcvt.h>
+#endif
 #include <X11/X.h>
 #include <X11/Xproto.h>
 #include <X11/Xos.h>
@@ -764,13 +767,37 @@ vncRandRModeGet(int width, int height)
     RRModePtr mode;
 
     memset(&modeInfo, 0, sizeof(modeInfo));
-    sprintf(name, "%dx%d", width, height);
 
+#ifdef HAVE_LIBXCVT
+    struct libxcvt_mode_info *cvtMode;
+
+    cvtMode = libxcvt_gen_mode_info(width, height, 60.0, false, false);
+
+    modeInfo.width      = cvtMode->hdisplay;
+    modeInfo.height     = cvtMode->vdisplay;
+    modeInfo.dotClock   = cvtMode->dot_clock * 1000.0;
+    modeInfo.hSyncStart = cvtMode->hsync_start;
+    modeInfo.hSyncEnd   = cvtMode->hsync_end;
+    modeInfo.hTotal     = cvtMode->htotal;
+    modeInfo.vSyncStart = cvtMode->vsync_start;
+    modeInfo.vSyncEnd   = cvtMode->vsync_end;
+    modeInfo.vTotal     = cvtMode->vtotal;
+    modeInfo.modeFlags  = cvtMode->mode_flags;
+
+    free(cvtMode);
+
+    /* libxcvt rounds up to multiples of 8, so override them here */
+    modeInfo.width = width;
+    modeInfo.height = height;
+#else
     modeInfo.width = width;
     modeInfo.height = height;
     modeInfo.hTotal = width;
     modeInfo.vTotal = height;
     modeInfo.dotClock = ((CARD32) width * (CARD32) height * 60);
+#endif
+
+    sprintf(name, "%dx%d", width, height);
     modeInfo.nameLength = strlen(name);
     mode = RRModeGet(&modeInfo, name);
     if (mode == NULL)
diff --git a/unix/xserver120.patch b/unix/xserver120.patch
index 9bc51822ab..d36e5075f2 100644
--- a/unix/xserver120.patch
+++ b/unix/xserver120.patch
@@ -10,7 +10,7 @@ index 0909cc5b4..c01873200 100644
  AC_PROG_LN_S
  LT_PREREQ([2.2])
  LT_INIT([disable-static win32-dll])
-@@ -1735,6 +1736,14 @@ if test "x$XVFB" = xyes; then
+@@ -1735,6 +1736,19 @@ if test "x$XVFB" = xyes; then
  	AC_SUBST([XVFB_SYS_LIBS])
  fi
  
@@ -21,6 +21,11 @@ index 0909cc5b4..c01873200 100644
 +PKG_CHECK_MODULES(GBM, "$LIBGBM", [GBM=yes], [GBM=no])
 +if test "x$GBM" = xyes; then
 +	AC_DEFINE(HAVE_GBM, 1, [Have GBM support])
++fi
++
++PKG_CHECK_MODULES(LIBXCVT, "libxcvt", [XCVT=yes], [XCVT=no])
++if test "x$XCVT" = xyes; then
++	AC_DEFINE(HAVE_LIBXCVT, 1, [Have libxcvt support])
 +fi
  
  dnl Xnest DDX
@@ -126,6 +131,16 @@ diff --git a/include/dix-config.h.in b/include/dix-config.h.in
 index f8fc67067..d53c4e72f 100644
 --- a/include/dix-config.h.in
 +++ b/include/dix-config.h.in
+@@ -63,6 +63,9 @@
+ /* Has libunwind support */
+ #undef HAVE_LIBUNWIND
+
++/* Have libxcvt support */
++#undef HAVE_LIBXCVT
++
+ /* Define to 1 if you have the `cbrt' function. */
+ #undef HAVE_CBRT
+
 @@ -83,6 +83,9 @@
  /* Define to 1 if you have the <fcntl.h> header file. */
  #undef HAVE_FCNTL_H
diff --git a/unix/xserver21.patch b/unix/xserver21.patch
index 7f1e8d4f62..c4258adfe0 100644
--- a/unix/xserver21.patch
+++ b/unix/xserver21.patch
@@ -10,7 +10,7 @@ index fad7b5769..2c167de3d 100644
  AC_PROG_LN_S
  LT_PREREQ([2.2])
  LT_INIT([disable-static win32-dll])
-@@ -1720,6 +1721,14 @@ if test "x$XVFB" = xyes; then
+@@ -1720,6 +1721,19 @@ if test "x$XVFB" = xyes; then
  	AC_SUBST([XVFB_SYS_LIBS])
  fi
  
@@ -21,6 +21,11 @@ index fad7b5769..2c167de3d 100644
 +PKG_CHECK_MODULES(GBM, "$LIBGBM", [GBM=yes], [GBM=no])
 +if test "x$GBM" = xyes; then
 +	AC_DEFINE(HAVE_GBM, 1, [Have GBM support])
++fi
++
++PKG_CHECK_MODULES(LIBXCVT, "$LIBXCVT", [XCVT=yes], [XCVT=no])
++if test "x$XCVT" = xyes; then
++	AC_DEFINE(HAVE_LIBXCVT, 1, [Have libxcvt support])
 +fi
  
  dnl Xnest DDX
@@ -55,6 +60,16 @@ diff --git a/include/dix-config.h.in b/include/dix-config.h.in
 index 382d70609..04a4fd263 100644
 --- a/include/dix-config.h.in
 +++ b/include/dix-config.h.in
+@@ -63,6 +63,9 @@
+ /* Has libunwind support */
+ #undef HAVE_LIBUNWIND
+
++/* Have libxcvt support */
++#undef HAVE_LIBXCVT
++
+ /* Define to 1 if you have the `cbrt' function. */
+ #undef HAVE_CBRT
+
 @@ -77,6 +77,9 @@
  /* Define to 1 if you have the <fcntl.h> header file. */
  #undef HAVE_FCNTL_H