1 files changed, 13 insertions, 7 deletions
diff --git a/src/gallium/state_trackers/wgl/stw_device.c b/src/gallium/state_trackers/wgl/stw_device.c
index 4ece4e4979a..e65e71dc15f 100644
--- a/src/gallium/state_trackers/wgl/stw_device.c
+++ b/src/gallium/state_trackers/wgl/stw_device.c
@@ -41,8 +41,6 @@
 #include "stw_framebuffer.h"
 #include "stw_st.h"
 
-extern _glthread_Mutex OneTimeLock;
-
 
 struct stw_device *stw_dev = NULL;
 
@@ -50,7 +48,19 @@ static int
 stw_get_param(struct st_manager *smapi,
               enum st_manager_param param)
 {
-   return 0;
+   switch (param) {
+   case ST_MANAGER_BROKEN_INVALIDATE:
+      /*
+       * Force framebuffer validation on glViewport.
+       *
+       * Certain applications, like Rhinoceros 4, uses glReadPixels
+       * exclusively (never uses SwapBuffers), so framebuffers never get
+       * resized unless we check on glViewport.
+       */
+      return 1;
+   default:
+      return 0;
+   }
 }
 
 boolean
@@ -74,8 +84,6 @@ stw_init(const struct stw_winsys *stw_winsys)
    
    stw_dev->stw_winsys = stw_winsys;
 
-   _glthread_INIT_MUTEX(OneTimeLock);
-
    stw_dev->stapi = stw_st_create_api();
    stw_dev->smapi = CALLOC_STRUCT(st_manager);
    if (!stw_dev->stapi || !stw_dev->smapi)
@@ -168,8 +176,6 @@ stw_cleanup(void)
 
    stw_dev->screen->destroy(stw_dev->screen);
 
-   _glthread_DESTROY_MUTEX(OneTimeLock);
-
    /* glapi is statically linked: we can call the local destroy function. */
 #ifdef _GLAPI_NO_EXPORTS
    _glapi_destroy_multithread();