nouveau: create only 1 shared screen between vdpau and opengl

This fixes bug 73200 "vdpau-GL interop fails due to different screen
objects" in the same way radeon does.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>

src/gallium/drivers/nouveau/nouveau_screen.c

@@ -144,6 +144,12 @@ nouveau_screen_init(struct nouveau_screen *screen, struct nouveau_device *dev)
 	if (nv_dbg)
 	   nouveau_mesa_debug = atoi(nv_dbg);
 
+	/*
+	 * this is initialized to 1 in nouveau_drm_screen_create after screen
+	 * is fully constructed and added to the global screen list.
+	 */
+	screen->refcount = -1;
+
 	if (dev->chipset < 0xc0) {
 		data = &nv04_data;
 		size = sizeof(nv04_data);

src/gallium/drivers/nouveau/nouveau_screen.h

@@ -22,6 +22,8 @@ struct nouveau_screen {
 	struct nouveau_client *client;
 	struct nouveau_pushbuf *pushbuf;
 
+	int refcount;
+
 	unsigned vidmem_bindings; /* PIPE_BIND_* where VRAM placement is desired */
 	unsigned sysmem_bindings; /* PIPE_BIND_* where GART placement is desired */
 	unsigned lowmem_bindings; /* PIPE_BIND_* that require an address < 4 GiB */
@@ -112,6 +114,8 @@ nouveau_screen(struct pipe_screen *pscreen)
 	return (struct nouveau_screen *)pscreen;
 }
 
+boolean nouveau_drm_screen_unref(struct nouveau_screen *screen);
+
 boolean
 nouveau_screen_bo_get_handle(struct pipe_screen *pscreen,
 			     struct nouveau_bo *bo,

src/gallium/drivers/nouveau/nv30/nv30_screen.c

@@ -302,6 +302,9 @@ nv30_screen_destroy(struct pipe_screen *pscreen)
 {
    struct nv30_screen *screen = nv30_screen(pscreen);
 
+   if (!nouveau_drm_screen_unref(&screen->base))
+      return;
+
    if (screen->base.fence.current &&
        screen->base.fence.current->state >= NOUVEAU_FENCE_STATE_EMITTED) {
       nouveau_fence_wait(screen->base.fence.current);

src/gallium/drivers/nouveau/nv50/nv50_screen.c

@@ -287,6 +287,9 @@ nv50_screen_destroy(struct pipe_screen *pscreen)
 {
    struct nv50_screen *screen = nv50_screen(pscreen);
 
+   if (!nouveau_drm_screen_unref(&screen->base))
+      return;
+
    if (screen->base.fence.current) {
       nouveau_fence_wait(screen->base.fence.current);
       nouveau_fence_ref (NULL, &screen->base.fence.current);

src/gallium/drivers/nouveau/nvc0/nvc0_screen.c

@@ -333,6 +333,9 @@ nvc0_screen_destroy(struct pipe_screen *pscreen)
 {
    struct nvc0_screen *screen = nvc0_screen(pscreen);
 
+   if (!nouveau_drm_screen_unref(&screen->base))
+      return;
+
    if (screen->base.fence.current) {
       nouveau_fence_wait(screen->base.fence.current);
       nouveau_fence_ref(NULL, &screen->base.fence.current);

src/gallium/targets/dri-nouveau/Makefile.am

@@ -20,6 +20,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 # DEALINGS IN THE SOFTWARE.
 
+DRI_VERSION_SCRIPT = $(srcdir)/nouveau_dri.link
 include $(top_srcdir)/src/gallium/Automake.inc
 
 AM_CFLAGS = \

src/gallium/targets/dri-nouveau/nouveau_dri.link

@@ -0,0 +1,6 @@
+VERSION {
+	global:
+		__driDriverExtensions;
+		nouveau_drm_screen_create;
+	local: *;
+};

src/gallium/winsys/nouveau/drm/nouveau_drm_winsys.c

@@ -1,24 +1,83 @@
+#include <sys/stat.h>
 #include "pipe/p_context.h"
 #include "pipe/p_state.h"
 #include "util/u_format.h"
 #include "util/u_memory.h"
 #include "util/u_inlines.h"
+#include "util/u_hash_table.h"
+#include "os/os_thread.h"
 
 #include "nouveau_drm_public.h"
 
 #include "nouveau/nouveau_winsys.h"
 #include "nouveau/nouveau_screen.h"
 
-struct pipe_screen *
+static struct util_hash_table *fd_tab = NULL;
+
+pipe_static_mutex(nouveau_screen_mutex);
+
+boolean nouveau_drm_screen_unref(struct nouveau_screen *screen)
+{
+	int ret;
+	if (screen->refcount == -1)
+		return true;
+
+	pipe_mutex_lock(nouveau_screen_mutex);
+	ret = --screen->refcount;
+	assert(ret >= 0);
+	if (ret == 0)
+		util_hash_table_remove(fd_tab, intptr_to_pointer(screen->device->fd));
+	pipe_mutex_unlock(nouveau_screen_mutex);
+	return ret == 0;
+}
+
+static unsigned hash_fd(void *key)
+{
+    int fd = pointer_to_intptr(key);
+    struct stat stat;
+    fstat(fd, &stat);
+
+    return stat.st_dev ^ stat.st_ino ^ stat.st_rdev;
+}
+
+static int compare_fd(void *key1, void *key2)
+{
+    int fd1 = pointer_to_intptr(key1);
+    int fd2 = pointer_to_intptr(key2);
+    struct stat stat1, stat2;
+    fstat(fd1, &stat1);
+    fstat(fd2, &stat2);
+
+    return stat1.st_dev != stat2.st_dev ||
+           stat1.st_ino != stat2.st_ino ||
+           stat1.st_rdev != stat2.st_rdev;
+}
+
+PUBLIC struct pipe_screen *
 nouveau_drm_screen_create(int fd)
 {
 	struct nouveau_device *dev = NULL;
 	struct pipe_screen *(*init)(struct nouveau_device *);
+	struct nouveau_screen *screen;
 	int ret;
 
+	pipe_mutex_lock(nouveau_screen_mutex);
+	if (!fd_tab) {
+		fd_tab = util_hash_table_create(hash_fd, compare_fd);
+		if (!fd_tab)
+			goto err;
+	}
+
+	screen = util_hash_table_get(fd_tab, intptr_to_pointer(fd));
+	if (screen) {
+		screen->refcount++;
+		pipe_mutex_unlock(nouveau_screen_mutex);
+		return &screen->base;
+	}
+
 	ret = nouveau_device_wrap(fd, 0, &dev);
 	if (ret)
-		return NULL;
+		goto err;
 
 	switch (dev->chipset & ~0xf) {
 	case 0x30:
@@ -42,8 +101,19 @@ nouveau_drm_screen_create(int fd)
 	default:
 		debug_printf("%s: unknown chipset nv%02x\n", __func__,
 			     dev->chipset);
-		return NULL;
+		goto err;
 	}
 
-	return init(dev);
+	screen = (struct nouveau_screen*)init(dev);
+	if (!screen)
+		goto err;
+
+	util_hash_table_set(fd_tab, intptr_to_pointer(fd), screen);
+	screen->refcount = 1;
+	pipe_mutex_unlock(nouveau_screen_mutex);
+	return &screen->base;
+
+err:
+	pipe_mutex_unlock(nouveau_screen_mutex);
+	return NULL;
 }