4 files changed, 63 insertions, 2 deletions
diff --git a/src/mesa/drivers/dri/common/Makefile.am b/src/mesa/drivers/dri/common/Makefile.am
index ce4119d0fff..e9c4acaece5 100644
--- a/src/mesa/drivers/dri/common/Makefile.am
+++ b/src/mesa/drivers/dri/common/Makefile.am
@@ -32,6 +32,7 @@ AM_CFLAGS = \
 
 noinst_LTLIBRARIES = \
 	libdricommon.la \
+	libmegadriver_stub.la \
 	libdri_test_stubs.la
 
 libdricommon_la_SOURCES = \
@@ -43,4 +44,6 @@ libdri_test_stubs_la_SOURCES = \
 	dri_test.c
 libdri_test_stubs_la_CFLAGS = $(AM_CFLAGS) -DNO_MAIN
 
+libmegadriver_stub_la_SOURCES = megadriver_stub.c
+
 sysconf_DATA = drirc
diff --git a/src/mesa/drivers/dri/common/dri_util.c b/src/mesa/drivers/dri/common/dri_util.c
index 2a85703f2ad..c28b0fc4174 100644
--- a/src/mesa/drivers/dri/common/dri_util.c
+++ b/src/mesa/drivers/dri/common/dri_util.c
@@ -82,6 +82,23 @@ setupLoaderExtensions(__DRIscreen *psp,
 }
 
 /**
+ * This pointer determines which driver API we'll use in the case of the
+ * loader not passing us an explicit driver extensions list (that would,
+ * itself, contain a pointer to a driver API.)
+ *
+ * A driver's driDriverGetExtensions_drivername() can update this pointer to
+ * what it's returning, and a loader that is ignorant of createNewScreen2()
+ * will get the correct driver screen created, as long as no other
+ * driDriverGetExtensions() happened in between the first one and the
+ * createNewScreen().
+ *
+ * This allows the X Server to not require the significant dri_interface.h
+ * updates for doing createNewScreen2(), which would discourage backporting of
+ * the X Server patches to support the new loader interface.
+ */
+const struct __DriverAPIRec *globalDriverAPI = &driDriverAPI;
+
+/**
  * This is the first entrypoint in the driver called by the DRI driver loader
  * after dlopen()ing it.
  *
@@ -102,7 +119,7 @@ dri2CreateNewScreen2(int scrn, int fd,
 	return NULL;
 
     /* By default, use the global driDriverAPI symbol (non-megadrivers). */
-    psp->driver = &driDriverAPI;
+    psp->driver = globalDriverAPI;
 
     /* If the driver exposes its vtable through its extensions list
      * (megadrivers), use that instead.
diff --git a/src/mesa/drivers/dri/common/dri_util.h b/src/mesa/drivers/dri/common/dri_util.h
index 61c80bc4541..5b56061e299 100644
--- a/src/mesa/drivers/dri/common/dri_util.h
+++ b/src/mesa/drivers/dri/common/dri_util.h
@@ -116,7 +116,7 @@ struct __DriverAPIRec {
 };
 
 extern const struct __DriverAPIRec driDriverAPI;
-
+extern const struct __DriverAPIRec *globalDriverAPI;
 
 /**
  * Per-screen private driver information.
diff --git a/src/mesa/drivers/dri/common/megadriver_stub.c b/src/mesa/drivers/dri/common/megadriver_stub.c
new file mode 100644
index 00000000000..6bf5d73279a
--- /dev/null
+++ b/src/mesa/drivers/dri/common/megadriver_stub.c
@@ -0,0 +1,41 @@
+/*
+ * Copyright © 2013 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include "dri_util.h"
+
+static const
+__DRIconfig **stub_error_init_screen(__DRIscreen *psp)
+{
+   fprintf(stderr, "An updated DRI driver loader (libGL.so or X Server) is "
+           "required for this Mesa driver.\n");
+   return NULL;
+}
+
+/**
+ * This is a stub driDriverAPI that is referenced by dri_util.c but should
+ * never be used.
+ */
+const struct __DriverAPIRec driDriverAPI = {
+   .InitScreen = stub_error_init_screen,
+};