diff --git a/hw/xwayland/xwayland-output.c b/hw/xwayland/xwayland-output.c
index 04eb42e8e..f94aa0d35 100644
--- a/hw/xwayland/xwayland-output.c
+++ b/hw/xwayland/xwayland-output.c
@@ -35,7 +35,6 @@
 
 #include "xdg-output-unstable-v1-client-protocol.h"
 
-#define DEFAULT_DPI 96
 #define ALL_ROTATIONS (RR_Rotate_0   | \
                        RR_Rotate_90  | \
                        RR_Rotate_180 | \
@@ -148,34 +147,6 @@ output_get_new_size(struct xwl_output *xwl_output,
         *height = xwl_output->y + output_height;
 }
 
-/* Approximate some kind of mmpd (m.m. per dot) of the screen given the outputs
- * associated with it.
- *
- * It either calculates the mean mmpd of all the outputs or, if no reasonable
- * value could be calculated, defaults to the mmpd of a screen with a DPI value
- * of DEFAULT_DPI.
- */
-static double
-approximate_mmpd(struct xwl_screen *xwl_screen)
-{
-    struct xwl_output *it;
-    int total_width_mm = 0;
-    int total_width = 0;
-
-    xorg_list_for_each_entry(it, &xwl_screen->output_list, link) {
-        if (it->randr_output->mmWidth == 0)
-            continue;
-
-        total_width_mm += it->randr_output->mmWidth;
-        total_width += it->width;
-    }
-
-    if (total_width_mm != 0)
-        return (double)total_width_mm / total_width;
-    else
-        return 25.4 / DEFAULT_DPI;
-}
-
 static int
 xwl_set_pixmap_visit_window(WindowPtr window, void *data)
 {
@@ -214,7 +185,6 @@ static void
 update_screen_size(struct xwl_output *xwl_output, int width, int height)
 {
     struct xwl_screen *xwl_screen = xwl_output->xwl_screen;
-    double mmpd;
 
     if (xwl_screen->root_clip_mode == ROOT_CLIP_FULL)
         SetRootClip(xwl_screen->screen, ROOT_CLIP_NONE);
@@ -226,15 +196,8 @@ update_screen_size(struct xwl_output *xwl_output, int width, int height)
     xwl_screen->height = height;
     xwl_screen->screen->width = width;
     xwl_screen->screen->height = height;
-
-    if (xwl_output->width == width && xwl_output->height == height) {
-        xwl_screen->screen->mmWidth = xwl_output->randr_output->mmWidth;
-        xwl_screen->screen->mmHeight = xwl_output->randr_output->mmHeight;
-    } else {
-        mmpd = approximate_mmpd(xwl_screen);
-        xwl_screen->screen->mmWidth = width * mmpd;
-        xwl_screen->screen->mmHeight = height * mmpd;
-    }
+    xwl_screen->screen->mmWidth = (width * 25.4) / monitorResolution;
+    xwl_screen->screen->mmHeight = (height * 25.4) / monitorResolution;
 
     SetRootClip(xwl_screen->screen, xwl_screen->root_clip_mode);
 
diff --git a/hw/xwayland/xwayland-screen.c b/hw/xwayland/xwayland-screen.c
index 4e523fec1..18d8968c7 100644
--- a/hw/xwayland/xwayland-screen.c
+++ b/hw/xwayland/xwayland-screen.c
@@ -59,6 +59,8 @@
 static DevPrivateKeyRec xwl_screen_private_key;
 static DevPrivateKeyRec xwl_client_private_key;
 
+#define DEFAULT_DPI 96
+
 _X_NORETURN
 static void _X_ATTRIBUTE_PRINTF(1, 2)
 xwl_give_up(const char *f, ...)
@@ -594,6 +596,9 @@ xwl_screen_init(ScreenPtr pScreen, int argc, char **argv)
     xorg_list_init(&xwl_screen->window_list);
     xwl_screen->depth = 24;
 
+    if (!monitorResolution)
+        monitorResolution = DEFAULT_DPI;
+
     xwl_screen->display = wl_display_connect(NULL);
     if (xwl_screen->display == NULL) {
         ErrorF("could not connect to wayland server\n");
@@ -624,7 +629,7 @@ xwl_screen_init(ScreenPtr pScreen, int argc, char **argv)
 
     ret = fbScreenInit(pScreen, NULL,
                        xwl_screen->width, xwl_screen->height,
-                       96, 96, 0,
+                       monitorResolution, monitorResolution, 0,
                        BitsPerPixel(xwl_screen->depth));
     if (!ret)
         return FALSE;