[Mesa-dev] [PATCH v5 3/4] egl: implement __DRIbackgroundCallableExtension.isThreadSafe

[Gregory Hainaut]

v2:
bump version

v3:
Add code comment
s/IsGlThread/IsThread/ (and variation)
Include X11/Xlibint.h protected by ifdef

v5: based on Daniel feedback
Move non X11 code outside of X11 define
Always return true for Wayland

Signed-off-by: Gregory Hainaut <gregory.hainaut at gmail.com>
---
 src/egl/drivers/dri2/egl_dri2.c | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/egl/drivers/dri2/egl_dri2.c b/src/egl/drivers/dri2/egl_dri2.c
index 0be7132ac5..8891771e3f 100644
--- a/src/egl/drivers/dri2/egl_dri2.c
+++ b/src/egl/drivers/dri2/egl_dri2.c
@@ -48,20 +48,24 @@
 #include <GL/internal/dri_interface.h>
 #include "GL/mesa_glinterop.h"
 #include <sys/types.h>
 #include <sys/stat.h>
 
 #ifdef HAVE_WAYLAND_PLATFORM
 #include "wayland-drm.h"
 #include "wayland-drm-client-protocol.h"
 #endif
 
+#ifdef HAVE_X11_PLATFORM
+#include "X11/Xlibint.h"
+#endif
+
 #include "egl_dri2.h"
 #include "loader/loader.h"
 #include "util/u_atomic.h"
 
 /* The kernel header drm_fourcc.h defines the DRM formats below.  We duplicate
  * some of the definitions here so that building Mesa won't bleeding-edge
  * kernel headers.
  */
 #ifndef DRM_FORMAT_R8
 #define DRM_FORMAT_R8            fourcc_code('R', '8', ' ', ' ') /* [7:0] R */
@@ -85,24 +89,52 @@
 
 static void
 dri_set_background_context(void *loaderPrivate)
 {
    _EGLContext *ctx = _eglGetCurrentContext();
    _EGLThreadInfo *t = _eglGetCurrentThread();
 
    _eglBindContextToThread(ctx, t);
 }
 
+static GLboolean
+dri_is_thread_safe(void *loaderPrivate)
+{
+   struct dri2_egl_surface *dri2_surf = loaderPrivate;
+   _EGLDisplay *display =  dri2_surf->base.Resource.Display;
+
+#ifdef HAVE_X11_PLATFORM
+   Display *xdpy = (Display*)display->PlatformDisplay;
+
+   /* Check Xlib is running in thread safe mode when running on EGL/X11-xlib
+    * platform
+    *
+    * 'lock_fns' is the XLockDisplay function pointer of the X11 display 'dpy'.
+    * It wll be NULL if XInitThreads wasn't called.
+    */
+   if (display->Platform == _EGL_PLATFORM_X11 && xdpy && !xdpy->lock_fns)
+      return false;
+#endif
+
+#ifdef HAVE_WAYLAND_PLATFORM
+   if (display->Platform == _EGL_PLATFORM_WAYLAND)
+      return true;
+#endif
+
+   return true;
+}
+
 const __DRIbackgroundCallableExtension background_callable_extension = {
-   .base = { __DRI_BACKGROUND_CALLABLE, 1 },
+   .base = { __DRI_BACKGROUND_CALLABLE, 2 },
 
    .setBackgroundContext = dri_set_background_context,
+   .isThreadSafe         = dri_is_thread_safe,
 };
 
 const __DRIuseInvalidateExtension use_invalidate = {
    .base = { __DRI_USE_INVALIDATE, 1 }
 };
 
 static const EGLint dri2_to_egl_attribute_map[__DRI_ATTRIB_MAX] = {
    [__DRI_ATTRIB_BUFFER_SIZE ]          = EGL_BUFFER_SIZE,
    [__DRI_ATTRIB_LEVEL]                 = EGL_LEVEL,
    [__DRI_ATTRIB_RED_SIZE]              = EGL_RED_SIZE,
-- 
2.11.0