st/egl: Implement swapbuffer throttling

When doing copy swapbuffers using drm, throttle on outstanding copy operations.
Introduces a new environment variable, EGL_THROTTLE_FENCES that the
user can use to indicate the desired number of outstanding swapbuffers, or
disable throttling using EGL_THROTTLE_FENCES=0.

This can and perhaps should be extended to the pageflip case as well, since
with some hardware pageflips can be pipelined. In case the pageflip syncs, the
throttle operation will be a no-op anyway.

Update copyright notices.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>

1 files changed, 12 insertions, 3 deletions

diff --git a/src/gallium/state_trackers/egl/drm/modeset.c b/src/gallium/state_trackers/egl/drm/modeset.c
index 6eaa42fafb..3fff954090 100644
--- a/src/gallium/state_trackers/egl/drm/modeset.c
+++ b/src/gallium/state_trackers/egl/drm/modeset.c
@@ -3,6 +3,7 @@
  * Version:  7.9
  *
  * Copyright (C) 2010 LunarG Inc.
+ * Copyright (C) 2011 VMware Inc. All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -24,6 +25,7 @@
  *
  * Authors:
  *    Chia-I Wu <olv@lunarg.com>
+ *    Thomas Hellstrom <thellstrom@vmware.com>
  */
 
 #include "util/u_memory.h"
@@ -136,8 +138,12 @@ drm_surface_copy_swap(struct native_surface *nsurf)
    struct drm_surface *drmsurf = drm_surface(nsurf);
    struct drm_display *drmdpy = drmsurf->drmdpy;
 
-   if (!resource_surface_copy_swap(drmsurf->rsurf, &drmdpy->base) ||
-       !drm_surface_flush_frontbuffer(nsurf))
+   (void) resource_surface_throttle(drmsurf->rsurf);
+   if (!resource_surface_copy_swap(drmsurf->rsurf, &drmdpy->base))
+      return FALSE;
+
+   (void) resource_surface_flush(drmsurf->rsurf, &drmdpy->base);
+   if (!drm_surface_flush_frontbuffer(nsurf))
       return FALSE;
 
    drmsurf->sequence_number++;
@@ -218,7 +224,9 @@ drm_surface_present(struct native_surface *nsurf,
 static void
 drm_surface_wait(struct native_surface *nsurf)
 {
-   /* no-op */
+   struct drm_surface *drmsurf = drm_surface(nsurf);
+
+   resource_surface_wait(drmsurf->rsurf);
 }
 
 static void
@@ -226,6 +234,7 @@ drm_surface_destroy(struct native_surface *nsurf)
 {
    struct drm_surface *drmsurf = drm_surface(nsurf);
 
+   resource_surface_wait(drmsurf->rsurf);
    if (drmsurf->current_crtc.crtc)
          drmModeFreeCrtc(drmsurf->current_crtc.crtc);