xwayland: refactor EGL backends for wayland registry

To be able to check for availability of the Wayland interfaces required
to run a given EGL backend (either GBM or EGLStream for now), we need
to have each backend structures and vfuncs in place before we enter the
Wayland registry dance.

That basically means that we should init all backends at first, connect
to the Wayland compositor and query the available interfaces and then
decide which backend is available and should be used (or none if either
the Wayland interfaces or the EGL extensions are not available).

For this purpose, hold an egl_backend struct for each backend we are to
consider prior to connect to the Wayland display so that, when we get to
query the Wayland interfaces, everything is in place for each backend to
handle the various Wayland interfaces.

Eventually, when we need to chose which EGL backend to use for glamor,
the available Wayland interfaces and EGL extensions available are all
known to Xwayland.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

1 files changed, 75 insertions, 19 deletions

diff --git a/hw/xwayland/xwayland-glamor.c b/hw/xwayland/xwayland-glamor.c
index 3792dfa8c..2f64d0500 100644
--- a/hw/xwayland/xwayland-glamor.c
+++ b/hw/xwayland/xwayland-glamor.c
@@ -71,9 +71,20 @@ xwl_glamor_init_wl_registry(struct xwl_screen *xwl_screen,
                             uint32_t id, const char *interface,
                             uint32_t version)
 {
-    if (xwl_screen->egl_backend.init_wl_registry)
-        xwl_screen->egl_backend.init_wl_registry(xwl_screen, registry,
-                                                 id, interface, version);
+    if (xwl_screen->gbm_backend.is_available &&
+        xwl_screen->gbm_backend.init_wl_registry &&
+        xwl_screen->gbm_backend.init_wl_registry(xwl_screen,
+                                                 registry,
+                                                 id,
+                                                 interface,
+                                                 version)); /* no-op */
+    else if (xwl_screen->eglstream_backend.is_available &&
+             xwl_screen->eglstream_backend.init_wl_registry &&
+             xwl_screen->eglstream_backend.init_wl_registry(xwl_screen,
+                                                            registry,
+                                                            id,
+                                                            interface,
+                                                            version)); /* no-op */
 }
 
 Bool
@@ -95,8 +106,8 @@ xwl_glamor_pixmap_get_wl_buffer(PixmapPtr pixmap,
 {
     struct xwl_screen *xwl_screen = xwl_screen_get(pixmap->drawable.pScreen);
 
-    if (xwl_screen->egl_backend.get_wl_buffer_for_pixmap)
-        return xwl_screen->egl_backend.get_wl_buffer_for_pixmap(pixmap,
+    if (xwl_screen->egl_backend->get_wl_buffer_for_pixmap)
+        return xwl_screen->egl_backend->get_wl_buffer_for_pixmap(pixmap,
                                                                 width,
                                                                 height,
                                                                 created);
@@ -110,8 +121,8 @@ xwl_glamor_post_damage(struct xwl_window *xwl_window,
 {
     struct xwl_screen *xwl_screen = xwl_window->xwl_screen;
 
-    if (xwl_screen->egl_backend.post_damage)
-        xwl_screen->egl_backend.post_damage(xwl_window, pixmap, region);
+    if (xwl_screen->egl_backend->post_damage)
+        xwl_screen->egl_backend->post_damage(xwl_window, pixmap, region);
 }
 
 Bool
@@ -119,8 +130,8 @@ xwl_glamor_allow_commits(struct xwl_window *xwl_window)
 {
     struct xwl_screen *xwl_screen = xwl_window->xwl_screen;
 
-    if (xwl_screen->egl_backend.allow_commits)
-        return xwl_screen->egl_backend.allow_commits(xwl_window);
+    if (xwl_screen->egl_backend->allow_commits)
+        return xwl_screen->egl_backend->allow_commits(xwl_window);
     else
         return TRUE;
 }
@@ -165,17 +176,62 @@ glamor_egl_fd_name_from_pixmap(ScreenPtr screen,
 void
 xwl_glamor_init_backends(struct xwl_screen *xwl_screen, Bool use_eglstream)
 {
+#ifdef GLAMOR_HAS_GBM
+    xwl_glamor_init_gbm(xwl_screen);
+    if (!xwl_screen->gbm_backend.is_available && !use_eglstream)
+        ErrorF("xwayland glamor: GBM backend (default) is not available\n");
+#endif
 #ifdef XWL_HAS_EGLSTREAM
-    if (use_eglstream) {
-        if (!xwl_glamor_init_eglstream(xwl_screen)) {
-            ErrorF("xwayland glamor: failed to setup EGLStream backend\n");
-            use_eglstream = FALSE;
-        }
+    xwl_glamor_init_eglstream(xwl_screen);
+    if (!xwl_screen->eglstream_backend.is_available && use_eglstream)
+        ErrorF("xwayland glamor: EGLStream backend requested but not available\n");
+#endif
+}
+
+static Bool
+xwl_glamor_select_gbm_backend(struct xwl_screen *xwl_screen)
+{
+#ifdef GLAMOR_HAS_GBM
+    if (xwl_screen->gbm_backend.is_available &&
+        xwl_glamor_has_wl_interfaces(xwl_screen, &xwl_screen->gbm_backend)) {
+        xwl_screen->egl_backend = &xwl_screen->gbm_backend;
+        return TRUE;
     }
+    else
+        ErrorF("Missing Wayland requirements for glamor GBM backend\n");
 #endif
-    if (!use_eglstream && !xwl_glamor_init_gbm(xwl_screen)) {
-        ErrorF("xwayland glamor: failed to setup GBM backend, falling back to sw accel\n");
-        xwl_screen->glamor = 0;
+
+    return FALSE;
+}
+
+static Bool
+xwl_glamor_select_eglstream_backend(struct xwl_screen *xwl_screen)
+{
+#ifdef XWL_HAS_EGLSTREAM
+    if (xwl_screen->eglstream_backend.is_available &&
+        xwl_glamor_has_wl_interfaces(xwl_screen, &xwl_screen->eglstream_backend)) {
+        ErrorF("glamor: Using nvidia's EGLStream interface, direct rendering impossible.\n");
+        ErrorF("glamor: Performance may be affected. Ask your vendor to support GBM!\n");
+        xwl_screen->egl_backend = &xwl_screen->eglstream_backend;
+        return TRUE;
+    }
+    else
+        ErrorF("Missing Wayland requirements for glamor EGLStream backend\n");
+#endif
+
+    return FALSE;
+}
+
+void
+xwl_glamor_select_backend(struct xwl_screen *xwl_screen, Bool use_eglstream)
+{
+    if (use_eglstream) {
+        if (!xwl_glamor_select_eglstream_backend(xwl_screen))
+            xwl_glamor_select_gbm_backend(xwl_screen);
+    }
+    else {
+        if (!xwl_glamor_select_gbm_backend(xwl_screen))
+            xwl_glamor_select_eglstream_backend(xwl_screen);
     }
 }
 
@@ -191,7 +247,7 @@ xwl_glamor_init(struct xwl_screen *xwl_screen)
         return FALSE;
     }
 
-    if (!xwl_screen->egl_backend.init_egl(xwl_screen)) {
+    if (!xwl_screen->egl_backend->init_egl(xwl_screen)) {
         ErrorF("EGL setup failed, disabling glamor\n");
         return FALSE;
     }
@@ -201,7 +257,7 @@ xwl_glamor_init(struct xwl_screen *xwl_screen)
         return FALSE;
     }
 
-    if (!xwl_screen->egl_backend.init_screen(xwl_screen)) {
+    if (!xwl_screen->egl_backend->init_screen(xwl_screen)) {
         ErrorF("EGL backend init_screen() failed, disabling glamor\n");
         return FALSE;
     }