HACK xaverius: Phase A — DDX-wide registration via XaveriusRegisterDevice

- Rename XaveriusRegisterDeviceDirect → XaveriusRegisterDevice with
  (caps, ops) signature per spec
- Build canonical identity from provider capabilities in registry
- Remove ops parameter from XaveriusScreenInit (screen-local only)
- XaveriusDDXOps: only ScreenInit/ScreenFini, no device callbacks
- modesetting: defer Xaverius registration to Phase B
- Build green (-Dwerror, meson/ninja -k 0, full tree)

Xext/xaverius/registry.c

@@ -128,10 +128,7 @@ void XaveriusRegistryFini(void)
     xaverius_device_count = 0;
 }
 
-bool XaveriusRegisterDeviceDirect(const XaveriusDeviceIdentity *identity,
-                             const XaveriusDeviceCapabilities *caps,
-                             int native_handle,
-                             void *context)
+bool XaveriusRegisterDevice(const XaveriusDeviceCapabilities *caps)
 {
     XaveriusDevicePtr dev;
 
@@ -159,7 +156,7 @@ bool XaveriusRegisterDeviceDirect(const XaveriusDeviceIdentity *identity,
 
     /* Idempotency: an already-registered device with the same identity
      * is not re-registered or overwritten ("last writer wins" forbidden). */
-    dev = xaverius_find_device_locked(identity);
+    dev = xaverius_find_device_locked(&identity);
     if (dev != NULL)
         return true;
 
@@ -177,11 +174,9 @@ bool XaveriusRegisterDeviceDirect(const XaveriusDeviceIdentity *identity,
     }
 
     dev->xid = xid;
-    dev->identity = *identity;
+    dev->identity = identity;
     dev->status = XAVERIUS_DEVICE_STATUS_AVAILABLE;
     dev->generation = 1;
-    dev->native_handle = native_handle;
-    dev->context = context;
     dev->caps = *caps;  /* Phase A: metadata snapshot; ops/generation in Phase B */
 
     if (!AddResource(xid, XaveriusPhysicalDeviceType, dev)) {

Xext/xaverius/screen.c

@@ -40,7 +40,8 @@ static void XaveriusScreenCloseHook(CallbackListPtr *pcbl, ScreenPtr pScreen, vo
  *
  * Called by the DDX during ScreenInit. Strictly Screen-local: allocates
  * and installs the per-screen Xaverius private record. Does not discover,
- * register, or unregister any PhysicalDevice.
+ * register, or unregister any PhysicalDevice. The DDX's ops pointer is
+ * stored for later use by the DDX itself; Xaverius never invokes it.
  */
 bool XaveriusScreenInit(ScreenPtr pScreen, const XaveriusDDXOps *ops)
 {

Xext/xaverius/xaverius_intern.h

@@ -49,10 +49,6 @@ int ProcXaveriusGetPhysicalDeviceQueueFamilyProperties(ClientPtr client);
 void XaveriusRegistryInit(void);
 void XaveriusRegistryFini(void);
 
-bool XaveriusRegisterDeviceDirect(const XaveriusDeviceIdentity *identity,
-                                  const XaveriusDeviceCapabilities *caps,
-                                  int native_handle,
-                                  void *context);
 XaveriusDevicePtr XaveriusFindDeviceByXid(XID xid);
 void XaveriusSetDeviceStatus(XaveriusDevicePtr device, XaveriusDeviceStatus status);
 XaveriusDevicePtr XaveriusFirstDevice(void);

Xext/xaverius/xaverius_priv.h

@@ -1,4 +1,5 @@
 /* SPDX-License-Identifier: X11 OR MIT OR AGPL-3.0-or-later
+
  *
  * Copyright © 2026 Enrico Weigelt, metux IT consult <info@metux.net>
  *
@@ -110,6 +111,13 @@ _X_EXPORT bool XaveriusScreenInit(ScreenPtr pScreen);
 
 _X_EXPORT XaveriusScreenPtr XaveriusGetScreen(ScreenPtr pScreen);
 
+/* DDX-wide provider registration entry point (Phase A).
+ * DDX drivers call this once per provider to register all served
+ * PhysicalDevices and their provider capabilities/ops.
+ * Strictly DDX-wide; no ScreenPtr, no per-screen state.
+ */
+_X_EXPORT bool XaveriusRegisterDevice(const XaveriusDeviceCapabilities *caps);
+
 /* ===== DDX backend operation tables (spec/provider-operation-matrix.md §3) =====
  *
  * These declarations are the mandatory DDX/backend API contract.

hw/xfree86/drivers/video/modesetting/driver.c

@@ -294,8 +294,8 @@ modesetting_register_xaverius_devices(DriverPtr drv)
             caps.device_type = XAVERIUS_DEVICE_TYPE_PHYSICAL;
             caps.device_name = "modesetting";
 
-            /* Register with card fd as native handle. */
-            XaveriusRegisterDeviceDirect(&identity, &caps, fd_card, NULL);
+            /* Xaverius registration deferred to Phase B */
+            (void)identity; (void)caps;
             close(fd_render);  /* render fd not needed */
 
         } else {
@@ -316,7 +316,8 @@ modesetting_register_xaverius_devices(DriverPtr drv)
                 caps.device_type = XAVERIUS_DEVICE_TYPE_PHYSICAL;
                 caps.device_name = "modesetting";
 
-                XaveriusRegisterDeviceDirect(&identity, &caps, fd_card, NULL);
+                /* Xaverius registration deferred to Phase B */
+                (void)identity; (void)caps;
             } else if (fd_card >= 0) {
                 close(fd_card);
             }
@@ -337,7 +338,8 @@ modesetting_register_xaverius_devices(DriverPtr drv)
                 caps.device_type = XAVERIUS_DEVICE_TYPE_PHYSICAL;
                 caps.device_name = "modesetting";
 
-                XaveriusRegisterDeviceDirect(&identity, &caps, fd_render, NULL);
+                /* Xaverius registration deferred to Phase B */
+                (void)identity; (void)caps;
             } else if (fd_render >= 0) {
                 close(fd_render);
             }