Add option for backwards compatibility

hw/xwayland/xwayland-output.c

@@ -287,8 +287,10 @@ output_calc_global_scale( struct xwl_screen *xwl_screen)
     struct xwl_output *it;
     int32_t scale = 1;
 
+    if (!xwl_screen->multidpi)
+        return;
     if (!xwl_screen->xdg_output_manager)
-        // global scaling is only possible when logical sizes are available
+        // multi dpi scaling is only possible when logical sizes are available
         return;
 
     xorg_list_for_each_entry(it, &xwl_screen->output_list, link) {

hw/xwayland/xwayland.c

@@ -91,6 +91,7 @@ ddxUseMsg(void)
     ErrorF("-wm fd                 create X client for wm on given fd\n");
     ErrorF("-listen fd             add give fd as a listen socket\n");
     ErrorF("-eglstream             use eglstream backend for nvidia GPUs\n");
+    ErrorF("-multidpi              multi dpi emulation, requires wm support\n");
 }
 
 static int wm_fd = -1;
@@ -125,6 +126,9 @@ ddxProcessArgument(int argc, char *argv[], int i)
     else if (strcmp(argv[i], "-eglstream") == 0) {
         return 1;
     }
+    else if (strcmp(argv[i], "-multidpi") == 0) {
+        return 1;
+    }
 
     return 0;
 }
@@ -991,6 +995,9 @@ xwl_screen_init(ScreenPtr pScreen, int argc, char **argv)
             ErrorF("xwayland glamor: this build does not have EGLStream support\n");
 #endif
         }
+        else if (strcmp(argv[i], "-multidpi") == 0) {
+            xwl_screen->multidpi = 1;
+        }
     }
 
 #ifdef XWL_HAS_GLAMOR

hw/xwayland/xwayland.h

@@ -123,6 +123,7 @@ struct xwl_screen {
     int rootless;
     int glamor;
     int present;
+    int multidpi;
 
     CreateScreenResourcesProcPtr CreateScreenResources;
     CloseScreenProcPtr CloseScreen;