1 files changed, 64 insertions, 12 deletions

diff --git a/mesalib/src/mesa/drivers/dri/common/dri_util.c b/mesalib/src/mesa/drivers/dri/common/dri_util.c
index db44eede6..c28b0fc41 100644
--- a/mesalib/src/mesa/drivers/dri/common/dri_util.c
+++ b/mesalib/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.
  *
@@ -89,9 +106,10 @@ setupLoaderExtensions(__DRIscreen *psp,
  * Display.
  */
 static __DRIscreen *
-dri2CreateNewScreen(int scrn, int fd,
-		    const __DRIextension **extensions,
-		    const __DRIconfig ***driver_configs, void *data)
+dri2CreateNewScreen2(int scrn, int fd,
+                     const __DRIextension **extensions,
+                     const __DRIextension **driver_extensions,
+                     const __DRIconfig ***driver_configs, void *data)
 {
     static const __DRIextension *emptyExtensionList[] = { NULL };
     __DRIscreen *psp;
@@ -100,7 +118,20 @@ dri2CreateNewScreen(int scrn, int fd,
     if (!psp)
 	return NULL;
 
-    psp->driver = &driDriverAPI;
+    /* By default, use the global driDriverAPI symbol (non-megadrivers). */
+    psp->driver = globalDriverAPI;
+
+    /* If the driver exposes its vtable through its extensions list
+     * (megadrivers), use that instead.
+     */
+    if (driver_extensions) {
+       for (int i = 0; driver_extensions[i]; i++) {
+          if (strcmp(driver_extensions[i]->name, __DRI_DRIVER_VTABLE) == 0) {
+             psp->driver =
+                ((__DRIDriverVtableExtension *)driver_extensions[i])->vtable;
+          }
+       }
+    }
 
     setupLoaderExtensions(psp, extensions);
 
@@ -154,12 +185,31 @@ dri2CreateNewScreen(int scrn, int fd,
     return psp;
 }
 
+static __DRIscreen *
+dri2CreateNewScreen(int scrn, int fd,
+		    const __DRIextension **extensions,
+		    const __DRIconfig ***driver_configs, void *data)
+{
+   return dri2CreateNewScreen2(scrn, fd, extensions, NULL,
+                               driver_configs, data);
+}
+
 /** swrast driver createNewScreen entrypoint. */
 static __DRIscreen *
-driCreateNewScreen(int scrn, const __DRIextension **extensions,
-		   const __DRIconfig ***driver_configs, void *data)
+driSWRastCreateNewScreen(int scrn, const __DRIextension **extensions,
+                         const __DRIconfig ***driver_configs, void *data)
+{
+   return dri2CreateNewScreen2(scrn, -1, extensions, NULL,
+                               driver_configs, data);
+}
+
+static __DRIscreen *
+driSWRastCreateNewScreen2(int scrn, const __DRIextension **extensions,
+                          const __DRIextension **driver_extensions,
+                          const __DRIconfig ***driver_configs, void *data)
 {
-   return dri2CreateNewScreen(scrn, -1, extensions, driver_configs, data);
+   return dri2CreateNewScreen2(scrn, -1, extensions, driver_extensions,
+                               driver_configs, data);
 }
 
 /**
@@ -688,7 +738,7 @@ const __DRIcoreExtension driCoreExtension = {
 
 /** DRI2 interface */
 const __DRIdri2Extension driDRI2Extension = {
-    .base = { __DRI_DRI2, 3 },
+    .base = { __DRI_DRI2, 4 },
 
     .createNewScreen            = dri2CreateNewScreen,
     .createNewDrawable          = dri2CreateNewDrawable,
@@ -697,15 +747,17 @@ const __DRIdri2Extension driDRI2Extension = {
     .createNewContextForAPI     = dri2CreateNewContextForAPI,
     .allocateBuffer             = dri2AllocateBuffer,
     .releaseBuffer              = dri2ReleaseBuffer,
-    .createContextAttribs       = dri2CreateContextAttribs
+    .createContextAttribs       = dri2CreateContextAttribs,
+    .createNewScreen2           = dri2CreateNewScreen2,
 };
 
 const __DRIswrastExtension driSWRastExtension = {
-    { __DRI_SWRAST, __DRI_SWRAST_VERSION },
-    driCreateNewScreen,
+    { __DRI_SWRAST, 4 },
+    driSWRastCreateNewScreen,
     dri2CreateNewDrawable,
     dri2CreateNewContextForAPI,
-    dri2CreateContextAttribs
+    dri2CreateContextAttribs,
+    driSWRastCreateNewScreen2,
 };
 
 const __DRI2configQueryExtension dri2ConfigQueryExtension = {