wip

24 files changed, 396 insertions, 89 deletions

diff --git a/configs/default b/configs/default
index 0582a0210a..d401bf6258 100644
--- a/configs/default
+++ b/configs/default
@@ -61,7 +61,7 @@ GLESv2_LIB = GLESv2
 VG_LIB = OpenVG
 GLAPI_LIB = glapi
 WAYLAND_EGL_LIB = wayland-egl
-
+GBM_LIB = gbm
 
 # Library names (actual file names)
 GL_LIB_NAME = lib$(GL_LIB).so
@@ -157,6 +157,9 @@ DRI_DRIVER_SEARCH_DIR = $(DRI_DRIVER_INSTALL_DIR)
 # EGL driver install directory
 EGL_DRIVER_INSTALL_DIR = $(INSTALL_LIB_DIR)/egl
 
+# gbm backend install directory
+GBM_BACKEND_INSTALL_DIR = $(INSTALL_LIB_DIR)/gbm
+
 # Xorg driver install directory (for xorg state-tracker)
 XORG_DRIVER_INSTALL_DIR = $(INSTALL_LIB_DIR)/xorg/modules/drivers
 
diff --git a/src/egl/drivers/dri2/Makefile b/src/egl/drivers/dri2/Makefile
index 90888f2ee7..39b720a54e 100644
--- a/src/egl/drivers/dri2/Makefile
+++ b/src/egl/drivers/dri2/Makefile
@@ -13,6 +13,7 @@ EGL_INCLUDES = \
 	-I$(TOP)/src/egl/main \
 	-I$(TOP)/src/mapi \
 	-I$(TOP)/src/ \
+	-I$(TOP)/src/gbm/main \
 	-DDEFAULT_DRIVER_DIR=\"$(DRI_DRIVER_SEARCH_DIR)\" \
 	$(LIBUDEV_CFLAGS) \
 	$(LIBDRM_CFLAGS)
diff --git a/src/egl/drivers/dri2/egl_dri2.h b/src/egl/drivers/dri2/egl_dri2.h
index 6c9a832fdd..a29de1a60f 100644
--- a/src/egl/drivers/dri2/egl_dri2.h
+++ b/src/egl/drivers/dri2/egl_dri2.h
@@ -44,7 +44,7 @@
 #include <GL/gl.h>
 #include <GL/internal/dri_interface.h>
 
-#include <gbm/dri_internal.h>
+#include <gbm/backends/dri/dri_internal.h>
 
 #include "eglconfig.h"
 #include "eglcontext.h"
diff --git a/src/gallium/state_trackers/egl/Makefile b/src/gallium/state_trackers/egl/Makefile
index 7ced8d3c50..549b7aeba2 100644
--- a/src/gallium/state_trackers/egl/Makefile
+++ b/src/gallium/state_trackers/egl/Makefile
@@ -33,7 +33,7 @@ wayland_INCLUDES = \
 wayland_SOURCES = $(wildcard wayland/*.c)
 wayland_OBJECTS = $(wayland_SOURCES:.c=.o)
 
-drm_INCLUDES = -I$(TOP)/src/gallium/winsys $(shell pkg-config --cflags-only-I libdrm) -I$(TOP)/src/
+drm_INCLUDES = -I$(TOP)/src/gallium/winsys $(shell pkg-config --cflags-only-I libdrm) -I$(TOP)/src/ -I$(TOP)/src/gbm/main
 drm_SOURCES = $(wildcard drm/*.c)
 drm_OBJECTS = $(drm_SOURCES:.c=.o)
 
diff --git a/src/gallium/state_trackers/egl/drm/native_drm.c b/src/gallium/state_trackers/egl/drm/native_drm.c
index 2773611c29..d386140336 100644
--- a/src/gallium/state_trackers/egl/drm/native_drm.c
+++ b/src/gallium/state_trackers/egl/drm/native_drm.c
@@ -33,7 +33,7 @@
 
 #include "native_drm.h"
 
-#include "gbm/gallium_drm_internal.h"
+#include "gbm/backends/gallium_drm/gallium_drm_internal.h"
 
 #ifdef HAVE_LIBUDEV
 #include <libudev.h>
diff --git a/src/gbm/Makefile b/src/gbm/Makefile
index 0e8764a105..19543ec3be 100644
--- a/src/gbm/Makefile
+++ b/src/gbm/Makefile
@@ -1,84 +1,31 @@
-# src/egl/Makefile
+# src/gbm/Makefile
 
 TOP = ../..
 include $(TOP)/configs/current
 
-PIPE_PREFIX := pipe_
+SUBDIRS = backends main
 
-INCLUDE_DIRS = -I$(TOP)/include \
-               -I$(TOP)/src/gallium/auxiliary \
-               -I$(TOP)/src/gallium/include
 
-HEADERS =		\
-	common.h	\
-	internal.h	\
-	gbm.h	
+default: subdirs
 
-SOURCES =		\
-	api.c		\
-	common.c	\
-	dri.c           \
-        gallium_drm.c
 
-OBJECTS = $(SOURCES:.c=.o)
+subdirs:
+	@for dir in $(SUBDIRS) ; do \
+		if [ -d $$dir ] ; then \
+			(cd $$dir && $(MAKE)) || exit 1 ; \
+		fi \
+	done
 
-# use dl*() to load drivers
-LOCAL_CFLAGS = -D_OS_UNIX=1 $(LIBDRM_CFLAGS) $(LIBUDEV_CFLAGS) $(DLOPEN_CFLAGS)
-LOCAL_LIBS = \
-	$(TOP)/src/gallium/drivers/identity/libidentity.a \
-	$(TOP)/src/gallium/drivers/trace/libtrace.a \
-	$(TOP)/src/gallium/drivers/rbug/librbug.a \
-	$(GALLIUM_AUXILIARIES)
-
-GBM_LIB_DEPS += $(LIBDRM_LIB) $(LIBUDEV_LIBS) $(DLOPEN_LIBS)
-
-LOCAL_CFLAGS += \
-	-DDEFAULT_DRIVER_DIR=\"$(DRI_DRIVER_SEARCH_DIR)\" \
-	-D_EGL_GALLIUM_DRIVER_SEARCH_DIR=\"$(EGL_DRIVER_INSTALL_DIR)\" \
-	-DPIPE_PREFIX=\"$(PIPE_PREFIX)\"
-
-.c.o:
-	$(CC) -c $(INCLUDE_DIRS) $(CFLAGS) $(LOCAL_CFLAGS) $< -o $@
-
-
-default: depend library
-
-
-library: $(TOP)/$(LIB_DIR)/libgbm.so
-
-$(TOP)/$(LIB_DIR)/libgbm.so: $(OBJECTS) $(LOCAL_LIBS)
-	$(MKLIB) -o gbm -linker '$(CC)' -ldflags '$(LDFLAGS)' \
-		-major 1 -minor 0 \
-		-install $(TOP)/$(LIB_DIR) $(MKLIB_OPTIONS) \
-		-L$(TOP)/$(LIB_DIR) $(GBM_LIB_DEPS) \
-		$(OBJECTS) $(LOCAL_LIBS)
-
-install-headers:
-	$(INSTALL) -d $(DESTDIR)$(INSTALL_INC_DIR)/
-	$(INSTALL) -m 644 $(TOP)/src/gbm/gbm.h \
-		$(DESTDIR)$(INSTALL_INC_DIR)
-
-
-PKG_CONFIG_DIR = $(INSTALL_LIB_DIR)/pkgconfig
-
-
-install: default install-headers
-	$(INSTALL) -d $(DESTDIR)$(INSTALL_LIB_DIR)
-	$(MINSTALL) $(TOP)/$(LIB_DIR)/libgbm.so* \
-		$(DESTDIR)$(INSTALL_LIB_DIR)
+install:
+	@for dir in $(SUBDIRS) ; do \
+		if [ -d $$dir ] ; then \
+			(cd $$dir && $(MAKE) install) || exit 1 ; \
+		fi \
+	done
 
 clean:
-	-rm -f *.o
-	-rm -f depend depend.bak
-
-
-depend: $(SOURCES) $(HEADERS)
-	@ echo "running $(MKDEP)"
-	@ rm -f depend
-	@ touch depend
-	$(MKDEP) $(MKDEP_OPTIONS) $(DEFINES) $(INCLUDE_DIRS) \
-		$(SOURCES) $(HEADERS) > /dev/null 2>/dev/null
-
-
--include depend
-# DO NOT DELETE
+	-@for dir in $(SUBDIRS) ; do \
+		if [ -d $$dir ] ; then \
+			(cd $$dir && $(MAKE) clean) ; \
+		fi \
+	done
diff --git a/src/gbm/backends/Makefile b/src/gbm/backends/Makefile
new file mode 100644
index 0000000000..994bbba878
--- /dev/null
+++ b/src/gbm/backends/Makefile
@@ -0,0 +1,32 @@
+# src/gbm/backends/Makefile
+
+TOP = ../../..
+include $(TOP)/configs/current
+
+# SUBDIRS = $(EGL_DRIVERS_DIRS)
+SUBDIRS = dri gallium_drm
+
+
+default: subdirs
+
+
+subdirs:
+	@for dir in $(SUBDIRS) ; do \
+		if [ -d $$dir ] ; then \
+			(cd $$dir ; $(MAKE)) || exit 1 ; \
+		fi \
+	done
+
+install:
+	@ for dir in $(SUBDIRS) ; do \
+		if [ -d $$dir ] ; then \
+			(cd $$dir ; $(MAKE) install) || exit 1 ; \
+		fi \
+	done
+
+clean:
+	@for dir in $(SUBDIRS) ; do \
+		if [ -d $$dir ] ; then \
+			(cd $$dir ; $(MAKE) clean) ; \
+		fi \
+	done
diff --git a/src/gbm/backends/Makefile.template b/src/gbm/backends/Makefile.template
new file mode 100644
index 0000000000..9df2ed930d
--- /dev/null
+++ b/src/gbm/backends/Makefile.template
@@ -0,0 +1,66 @@
+# src/gbm/backends/Makefile.template
+#
+# Backends should define
+#
+# GBM_BUILTIN, the driver is built-in or external
+# GBM_BACKEND, the driver name
+# GBM_SOURCES, the driver sources
+# GBM_INCLUDES, the include pathes
+# GBM_CFLAGS, additional CFLAGS
+# GBM_LIBS, additional LIBS
+#
+# before including this template.
+#
+
+
+GBM_BACKEND_PATH = $(TOP)/$(LIB_DIR)/gbm/$(GBM_BACKEND).so
+GBM_OBJECTS = $(GBM_SOURCES:.c=.o)
+
+# built-in or external
+ifeq ($(GBM_BUILTIN),true)
+GBM_TARGET = lib$(GBM_BACKEND).a
+GBM_INSTALL =
+else
+GBM_TARGET = $(GBM_BACKEND_PATH)
+GBM_INSTALL = install-so
+endif
+
+default: depend $(GBM_TARGET)
+
+$(GBM_BACKEND_PATH): $(GBM_BACKEND).so
+	@$(INSTALL) -d $(TOP)/$(LIB_DIR)/gbm
+	$(INSTALL) $< $(TOP)/$(LIB_DIR)/gbm
+
+$(GBM_BACKEND).so: $(GBM_OBJECTS) Makefile $(TOP)/src/gbm/backends/Makefile.template
+	@$(MKLIB) -o $(GBM_BACKEND).so -noprefix \
+		-linker '$(CC)' -ldflags '-L$(TOP)/$(LIB_DIR) $(LDFLAGS)' \
+		$(MKLIB_OPTIONS) \
+		$(GBM_OBJECTS) $(GBM_LIBS) -l$(GBM_LIB)
+
+lib$(GBM_BACKEND).a: $(GBM_OBJECTS) Makefile $(TOP)/src/gbm/backends/Makefile.template
+	@$(MKLIB) -o $(GBM_BACKEND) -static $(GBM_OBJECTS)
+
+.c.o:
+	$(CC) -c $(GBM_INCLUDES) $(CFLAGS) $(GBM_CFLAGS) $< -o $@
+
+install-so: $(GBM_BACKEND_PATH)
+	$(INSTALL) -d $(DESTDIR)$(GBM_BACKEND_INSTALL_DIR)
+	$(MINSTALL) $(GBM_BACKEND_PATH) $(DESTDIR)$(GBM_BACKEND_INSTALL_DIR)
+
+install: $(GBM_INSTALL)
+
+clean:
+	rm -f $(GBM_BACKEND).so
+	rm -f lib$(GBM_BACKEND).a
+	rm -f $(GBM_OBJECTS)
+	rm -f depend depend.bak
+
+depend: $(GBM_SOURCES)
+	@ echo "running $(MKDEP)"
+	@ rm -f depend
+	@ touch depend
+	$(MKDEP) $(MKDEP_OPTIONS) $(GBM_INCLUDES) $(GBM_SOURCES) \
+		>/dev/null 2>/dev/null
+
+sinclude depend
+# DO NOT DELETE
diff --git a/src/gbm/backends/dri/Makefile b/src/gbm/backends/dri/Makefile
new file mode 100644
index 0000000000..e47b39b01e
--- /dev/null
+++ b/src/gbm/backends/dri/Makefile
@@ -0,0 +1,28 @@
+# src/gbm/backends/dri/Makefile
+
+TOP = ../../../..
+include $(TOP)/configs/current
+
+GBM_BACKEND = gbm_dri
+GBM_SOURCES = gbm_dri.c u_drm_screen.c
+
+GBM_INCLUDES = \
+	-I$(TOP)/include \
+	-I$(TOP)/src/gbm/main \
+	-DDEFAULT_DRIVER_DIR=\"$(DRI_DRIVER_SEARCH_DIR)\" \
+	$(LIBUDEV_CFLAGS) \
+	$(LIBDRM_CFLAGS)
+
+# Includes for u_drm_screen.c
+GBM_INCLUDES += \
+        -I$(TOP)/src/gallium/auxiliary \
+        -I$(TOP)/src/gallium/include
+
+GBM_LIBS = $(LIBUDEV_LIBS) $(LIBDRM_LIB)
+
+GBM_CFLAGS =
+GBM_BUILTIN =
+#GBM_CFLAGS = -D_GBM_MAIN=_eglBuiltInDriverDRI2
+#GBM_BUILTIN = true
+
+include ../Makefile.template
diff --git a/src/gbm/dri_internal.h b/src/gbm/backends/dri/dri_internal.h
index a065a3c416..a065a3c416 100644
--- a/src/gbm/dri_internal.h
+++ b/src/gbm/backends/dri/dri_internal.h
diff --git a/src/gbm/dri.c b/src/gbm/backends/dri/gbm_dri.c
index a8c588a6ea..a2dd28c013 100644
--- a/src/gbm/dri.c
+++ b/src/gbm/backends/dri/gbm_dri.c
@@ -326,7 +326,7 @@ dri_destroy(struct gbm_device *gbm)
    free(dri);
 }
 
-struct gbm_device *
+static struct gbm_device *
 dri_device_create(int fd)
 {
    struct gbm_dri_device *dri;
@@ -351,3 +351,28 @@ dri_device_create(int fd)
 
    return &dri->base.base;
 }
+
+static int
+dri_probe(int fd)
+{
+   char *name;
+   int ret = 0;
+   
+   name = util_drm_fd_get_screen_name(fd);
+   if (name == NULL) {
+      ret = -1;
+   } else {
+      free(name);
+      ret = 0;
+   }
+
+   return ret;
+}
+
+
+GBM_EXPORT struct gbm_backend gbm_backend = {
+   .class_name = "drm",
+   .backend_name = "dri",
+   .probe = dri_probe,
+   .create_device = dri_device_create,
+};
diff --git a/src/gbm/backends/dri/u_drm_screen.c b/src/gbm/backends/dri/u_drm_screen.c
new file mode 120000
index 0000000000..9e5413df97
--- /dev/null
+++ b/src/gbm/backends/dri/u_drm_screen.c
@@ -0,0 +1 @@
+../../../gallium/auxiliary/util/u_drm_screen.c
\ No newline at end of file
diff --git a/src/gbm/backends/gallium_drm/Makefile b/src/gbm/backends/gallium_drm/Makefile
new file mode 100644
index 0000000000..0459635f08
--- /dev/null
+++ b/src/gbm/backends/gallium_drm/Makefile
@@ -0,0 +1,33 @@
+# src/gbm/backends/gallium_drm/Makefile
+
+TOP = ../../../..
+include $(TOP)/configs/current
+
+PIPE_PREFIX := pipe_
+
+GBM_BACKEND = gbm_gallium_drm
+GBM_SOURCES = gbm_gallium_drm.c
+
+GBM_INCLUDES = \
+	       -I$(TOP)/include \
+	       -I$(TOP)/src/gbm/main \
+	       $(LIBUDEV_CFLAGS) \
+	       $(LIBDRM_CFLAGS)
+
+GBM_INCLUDES += \
+		-I$(TOP)/src/gallium/auxiliary \
+		-I$(TOP)/src/gallium/include
+
+GBM_LIBS = $(LIBUDEV_LIBS) $(LIBDRM_LIB) \
+	   $(TOP)/src/gallium/drivers/identity/libidentity.a \
+	   $(TOP)/src/gallium/drivers/trace/libtrace.a \
+	   $(TOP)/src/gallium/drivers/rbug/librbug.a \
+	   $(GALLIUM_AUXILIARIES)
+
+
+GBM_CFLAGS = -D_EGL_GALLIUM_DRIVER_SEARCH_DIR=\"$(EGL_DRIVER_INSTALL_DIR)\" -DPIPE_PREFIX=\"$(PIPE_PREFIX)\"
+GBM_BUILTIN =
+#GBM_CFLAGS = -D_GBM_MAIN=_eglBuiltInDriverDRI2
+#GBM_BUILTIN = true
+
+include ../Makefile.template
diff --git a/src/gbm/gallium_drm_internal.h b/src/gbm/backends/gallium_drm/gallium_drm_internal.h
index 7f9bc081ae..7f9bc081ae 100644
--- a/src/gbm/gallium_drm_internal.h
+++ b/src/gbm/backends/gallium_drm/gallium_drm_internal.h
diff --git a/src/gbm/gallium_drm.c b/src/gbm/backends/gallium_drm/gbm_gallium_drm.c
index 19bc6a9a14..6b3fb1e4a9 100644
--- a/src/gbm/gallium_drm.c
+++ b/src/gbm/backends/gallium_drm/gbm_gallium_drm.c
@@ -141,15 +141,6 @@ create_drm_screen(const char *name, int fd)
       pmod->drmdd->create_screen(fd) : NULL;
 }
 
-
-
-
-
-
-
-
-
-
 static int
 gallium_screen_create(struct gbm_gallium_drm_device *gdrm)
 {
@@ -329,13 +320,14 @@ gbm_gallium_drm_destroy(struct gbm_device *gbm)
    FREE(gdrm);
 }
 
-struct gbm_device *
+static struct gbm_device *
 gbm_gallium_drm_device_create(int fd)
 {
    struct gbm_gallium_drm_device *dri;
    int ret;
 
    dri = calloc(1, sizeof *dri);
+   printf("create g3d\n");
 
    dri->base.base.fd = fd;
    dri->base.base.bo_create = gbm_gallium_drm_bo_create;
@@ -355,3 +347,28 @@ gbm_gallium_drm_device_create(int fd)
 
    return &dri->base.base;
 }
+
+static int
+gallium_drm_probe(int fd)
+{
+   char *name;
+   int ret = 0;
+   
+   name = util_drm_fd_get_screen_name(fd);
+   if (name == NULL) {
+      ret = -1;
+   } else {
+      free(name);
+      ret = 0;
+   }
+
+   return ret;
+}
+
+
+GBM_EXPORT struct gbm_backend gbm_backend = {
+   .class_name = "drm",
+   .backend_name = "gallium",
+   .probe = gallium_drm_probe,
+   .create_device = gbm_gallium_drm_device_create,
+};
diff --git a/src/gbm/main/Makefile b/src/gbm/main/Makefile
new file mode 100644
index 0000000000..08877ef2b5
--- /dev/null
+++ b/src/gbm/main/Makefile
@@ -0,0 +1,71 @@
+# src/gbm/main/Makefile
+
+TOP = ../../..
+include $(TOP)/configs/current
+
+INCLUDE_DIRS = -I$(TOP)/include
+
+HEADERS =		\
+	common.h	\
+	module.h	\
+	internal.h	\
+	gbm.h	
+
+SOURCES =		\
+	api.c		\
+	module.c	\
+	common.c
+
+OBJECTS = $(SOURCES:.c=.o)
+
+# use dl*() to load drivers
+LOCAL_CFLAGS = -D_OS_UNIX=1 $(LIBUDEV_CFLAGS) $(DLOPEN_CFLAGS) -DMODULEDIR='"$(GBM_BACKEND_INSTALL_DIR)"'
+LOCAL_LIBS =
+
+GBM_LIB_DEPS += $(LIBUDEV_LIBS) $(DLOPEN_LIBS)
+
+.c.o:
+	$(CC) -c $(INCLUDE_DIRS) $(CFLAGS) $(LOCAL_CFLAGS) $< -o $@
+
+
+default: depend library
+
+
+library: $(TOP)/$(LIB_DIR)/libgbm.so
+
+$(TOP)/$(LIB_DIR)/libgbm.so: $(OBJECTS) $(LOCAL_LIBS)
+	$(MKLIB) -o gbm -linker '$(CC)' -ldflags '$(LDFLAGS)' \
+		-major 1 -minor 0 \
+		-install $(TOP)/$(LIB_DIR) $(MKLIB_OPTIONS) \
+		-L$(TOP)/$(LIB_DIR) $(GBM_LIB_DEPS) \
+		$(OBJECTS) $(LOCAL_LIBS)
+
+install-headers:
+	$(INSTALL) -d $(DESTDIR)$(INSTALL_INC_DIR)/
+	$(INSTALL) -m 644 $(TOP)/src/gbm/main/gbm.h \
+		$(DESTDIR)$(INSTALL_INC_DIR)
+
+
+PKG_CONFIG_DIR = $(INSTALL_LIB_DIR)/pkgconfig
+
+
+install: default install-headers
+	$(INSTALL) -d $(DESTDIR)$(INSTALL_LIB_DIR)
+	$(MINSTALL) $(TOP)/$(LIB_DIR)/libgbm.so* \
+		$(DESTDIR)$(INSTALL_LIB_DIR)
+
+clean:
+	-rm -f *.o
+	-rm -f depend depend.bak
+
+
+depend: $(SOURCES) $(HEADERS)
+	@ echo "running $(MKDEP)"
+	@ rm -f depend
+	@ touch depend
+	$(MKDEP) $(MKDEP_OPTIONS) $(DEFINES) $(INCLUDE_DIRS) \
+		$(SOURCES) $(HEADERS) > /dev/null 2>/dev/null
+
+
+-include depend
+# DO NOT DELETE
diff --git a/src/gbm/api.c b/src/gbm/main/api.c
index f8aaf7b2a6..24e8c5615c 100644
--- a/src/gbm/api.c
+++ b/src/gbm/main/api.c
@@ -3,6 +3,7 @@
 
 #include "gbm.h"
 #include "internal.h"
+#include "module.h"
 
 GBM_EXPORT int
 gbm_device_get_fd(struct gbm_device *gbm)
@@ -28,8 +29,10 @@ gbm_device_create(int fd)
 {
    struct gbm_device *gbm;
 
-   gbm = dri_device_create(fd);
+   //gbm = dri_device_create(fd);
    //gbm = gbm_gallium_drm_device_create(fd);
+   struct gbm_backend *backend = find_backend(fd);
+   gbm = backend->create_device(fd);
    if (gbm == NULL)
       return NULL;
 
diff --git a/src/gbm/common.c b/src/gbm/main/common.c
index 9c5aac94fd..9c5aac94fd 100644
--- a/src/gbm/common.c
+++ b/src/gbm/main/common.c
diff --git a/src/gbm/common.h b/src/gbm/main/common.h
index ee33e972bb..ee33e972bb 100644
--- a/src/gbm/common.h
+++ b/src/gbm/main/common.h
diff --git a/src/gbm/common_drm.h b/src/gbm/main/common_drm.h
index 44985c42aa..44985c42aa 100644
--- a/src/gbm/common_drm.h
+++ b/src/gbm/main/common_drm.h
diff --git a/src/gbm/gbm.h b/src/gbm/main/gbm.h
index 9200ca5ae5..9200ca5ae5 100644
--- a/src/gbm/gbm.h
+++ b/src/gbm/main/gbm.h
diff --git a/src/gbm/internal.h b/src/gbm/main/internal.h
index 0ceef265e8..6f0d4f1f16 100644
--- a/src/gbm/internal.h
+++ b/src/gbm/main/internal.h
@@ -44,10 +44,20 @@ struct gbm_bo {
    union gbm_bo_handle  handle;
 };
 
+
+struct gbm_backend {
+   const char *class_name;
+   const char *backend_name;
+   int (*probe)(int fd);
+   struct gbm_device *(*create_device)(int fd);
+};
+
+#if 0
 struct gbm_device *
 dri_device_create(int fd);
 
 struct gbm_device *
 gbm_gallium_drm_device_create(int fd);
+#endif
 
 #endif
diff --git a/src/gbm/main/module.c b/src/gbm/main/module.c
new file mode 100644
index 0000000000..0a7b37adb1
--- /dev/null
+++ b/src/gbm/main/module.c
@@ -0,0 +1,61 @@
+#include <stdio.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <dlfcn.h>
+
+#include "module.h"
+
+static void *
+load_module(const char *name, const char *entrypoint)
+{
+   char path[PATH_MAX];
+   void *module, *init;
+
+   if (name[0] != '/')
+      snprintf(path, sizeof path, MODULEDIR "/%s", name);
+   else
+      snprintf(path, sizeof path, "%s", name);
+
+   module = dlopen(path, RTLD_LAZY);
+   if (!module) {
+      fprintf(stderr,
+              "failed to load module: %s\n", dlerror());
+      return NULL;
+   }
+
+   init = dlsym(module, entrypoint);
+   if (!init)
+      return NULL;
+
+   return init;
+}
+
+static const char *backends[] = {
+   "gbm_dri.so",
+   "gbm_gallium_drm.so",
+};
+
+#define ARRAY_SIZE(a) (sizeof(a)/sizeof((a)[0]))
+
+struct gbm_backend *
+find_backend(int fd)
+{
+   struct gbm_backend *backend = NULL;
+   int i;
+   const char *b;
+
+   b = getenv("GBM_BACKEND");
+   if (b)
+      backend = load_module(b, "gbm_backend");
+
+   for (i = 0; i < ARRAY_SIZE(backends) && backend == NULL; ++i) {
+      backend = load_module(backends[i], "gbm_backend");
+      if (backend && backend->probe(fd) == 0)
+         break;
+      else
+         backend = NULL;
+   }
+   
+   return backend;
+}
diff --git a/src/gbm/main/module.h b/src/gbm/main/module.h
new file mode 100644
index 0000000000..591062a93d
--- /dev/null
+++ b/src/gbm/main/module.h
@@ -0,0 +1,9 @@
+#ifndef MODULE_H_
+#define MODULE_H_
+
+#include "internal.h"
+
+struct gbm_backend *
+find_backend(int fd);
+
+#endif