kdrive/fbdev: Use ShadowFB by default

It can be disabled by passing `-noshadow` to the command-line args

Signed-off-by: stefan11111 <stefan11111@shitposting.expert>

hw/kdrive/fbdev/fbdev.c

@@ -35,6 +35,7 @@
 #endif
 
 const char *fbdevDevicePath = NULL;
+Bool fbDisableShadow = FALSE;
 
 static Bool
 fbdevInitialize(KdCardInfo * card, FbdevPriv * priv)
@@ -345,11 +346,14 @@ fbdevMapFramebuffer(KdScreenInfo * screen)
     KdPointerMatrix m;
     FbdevPriv *priv = screen->card->driver;
 
-    if (scrpriv->randr != RR_Rotate_0 ||
-        priv->fix.type != FB_TYPE_PACKED_PIXELS)
+    if (!fbDisableShadow) {
         scrpriv->shadow = TRUE;
-    else
+    } else if (scrpriv->randr != RR_Rotate_0 ||
+        priv->fix.type != FB_TYPE_PACKED_PIXELS) {
+        scrpriv->shadow = TRUE;
+    } else {
         scrpriv->shadow = FALSE;
+    }
 
     KdComputePointerMatrix(&m, scrpriv->randr, screen->width, screen->height);
 

hw/kdrive/fbdev/fbdev.h

@@ -50,6 +50,7 @@ typedef struct _fbdevScrPriv {
 
 extern KdCardFuncs fbdevFuncs;
 extern const char *fbdevDevicePath;
+extern Bool fbDisableShadow;
 
 Bool fbdevCardInit(KdCardInfo * card);
 

hw/kdrive/fbdev/fbinit.c

@@ -68,6 +68,8 @@ ddxUseMsg(void)
     ErrorF("\nXfbdev Device Usage:\n");
     ErrorF
         ("-fb path         Framebuffer device to use. Defaults to /dev/fb0\n");
+    ErrorF
+        ("-noshadow        Disable the ShadowFB layer if possible\n");
     ErrorF("\n");
 }
 
@@ -83,6 +85,11 @@ ddxProcessArgument(int argc, char **argv, int i)
         exit(1);
     }
 
+    if (!strcmp(argv[i], "-noshadow")) {
+        fbDisableShadow = TRUE;
+        return 1;
+    }
+
     return KdProcessArgument(argc, argv, i);
 }