dri2: Event driven buffer validation.

When a buffer invalidation event is received from the X server, the
"invalidate" hook of the DRI2 flush extension is executed: A generic
implementation (dri2InvalidateDrawable) is provided that just bumps
the "pStamp" sequence number in __DRIdrawableRec.

For old servers not supporting buffer invalidation events, the
invalidate hook will be called before flushing the fake front/back
buffer (that's typically once per frame -- not a lot worse than the
situation we were in before).

No effort has been made on preserving backwards compatibility with
version 2 of the flush extension, but I think it's acceptable because
AFAIK no released stack is making use of it.

Signed-off-by: Kristian Høgsberg <krh@bitplanet.net>

5 files changed, 20 insertions, 12 deletions

diff --git a/src/mesa/drivers/dri/common/dri_util.c b/src/mesa/drivers/dri/common/dri_util.c
index befe1675a0..b891fca2b1 100644
--- a/src/mesa/drivers/dri/common/dri_util.c
+++ b/src/mesa/drivers/dri/common/dri_util.c
@@ -454,7 +454,6 @@ driCreateNewDrawable(__DRIscreen *psp, const __DRIconfig *config,
 
     pdp->driScreenPriv = psp;
     pdp->driContextPriv = &psp->dummyContextPriv;
-    pdp->validBuffers = GL_FALSE;
 
     if (!(*psp->DriverAPI.CreateBuffer)(psp, pdp, &config->modes,
 					renderType == GLX_PIXMAP_BIT)) {
@@ -488,6 +487,9 @@ dri2CreateNewDrawable(__DRIscreen *screen,
     pdraw->pClipRects = &pdraw->dri2.clipRect;
     pdraw->pBackClipRects = &pdraw->dri2.clipRect;
 
+    pdraw->pStamp = &pdraw->dri2.stamp;
+    *pdraw->pStamp = pdraw->lastStamp + 1;
+
     return pdraw;
 }
 
@@ -949,4 +951,10 @@ driCalculateSwapUsage( __DRIdrawable *dPriv, int64_t last_swap_ust,
    return usage;
 }
 
+void
+dri2InvalidateDrawable(__DRIdrawable *drawable)
+{
+    drawable->dri2.stamp++;
+}
+
 /*@}*/
diff --git a/src/mesa/drivers/dri/common/dri_util.h b/src/mesa/drivers/dri/common/dri_util.h
index 8d02524f38..8f0cd4cf9d 100644
--- a/src/mesa/drivers/dri/common/dri_util.h
+++ b/src/mesa/drivers/dri/common/dri_util.h
@@ -295,7 +295,8 @@ struct __DRIdrawableRec {
     unsigned int index;
 
     /**
-     * Pointer to the "drawable has changed ID" stamp in the SAREA.
+     * Pointer to the "drawable has changed ID" stamp in the SAREA (or
+     * to dri2.stamp if DRI2 is being used).
      */
     unsigned int *pStamp;
 
@@ -377,9 +378,8 @@ struct __DRIdrawableRec {
      */
     unsigned int swap_interval;
 
-    GLboolean validBuffers;
-
     struct {
+	unsigned int stamp;
 	drm_clip_rect_t clipRect;
     } dri2;
 };
@@ -559,4 +559,7 @@ driCalculateSwapUsage( __DRIdrawable *dPriv,
 extern GLint
 driIntersectArea( drm_clip_rect_t rect1, drm_clip_rect_t rect2 );
 
+extern void
+dri2InvalidateDrawable(__DRIdrawable *drawable);
+
 #endif /* _DRI_UTIL_H_ */
diff --git a/src/mesa/drivers/dri/intel/intel_context.c b/src/mesa/drivers/dri/intel/intel_context.c
index fa2168b6ef..81d5a32476 100644
--- a/src/mesa/drivers/dri/intel/intel_context.c
+++ b/src/mesa/drivers/dri/intel/intel_context.c
@@ -366,8 +366,8 @@ intel_update_renderbuffers(__DRIcontext *context, __DRIdrawable *drawable)
        }
    }
 
-   drawable->validBuffers = GL_TRUE;
    driUpdateFramebufferSize(&intel->ctx, drawable);
+   drawable->lastStamp = drawable->dri2.stamp;
 }
 
 void
diff --git a/src/mesa/drivers/dri/intel/intel_screen.c b/src/mesa/drivers/dri/intel/intel_screen.c
index f7ce87e063..8eed8ee737 100644
--- a/src/mesa/drivers/dri/intel/intel_screen.c
+++ b/src/mesa/drivers/dri/intel/intel_screen.c
@@ -123,22 +123,19 @@ intelDRI2Flush(__DRIdrawable *drawable)
 }
 
 static void
-intelDRI2FlushInvalidate(__DRIdrawable *drawable)
+intelDRI2Invalidate(__DRIdrawable *drawable)
 {
    struct intel_context *intel = drawable->driContextPriv->driverPrivate;
 
    intel->using_dri2_swapbuffers = GL_TRUE;
-
-   intelDRI2Flush(drawable);
-   drawable->validBuffers = GL_FALSE;
-
+   dri2InvalidateDrawable(drawable);
    intel_update_renderbuffers(intel->driContext, drawable);
 }
 
 static const struct __DRI2flushExtensionRec intelFlushExtension = {
     { __DRI2_FLUSH, __DRI2_FLUSH_VERSION },
     intelDRI2Flush,
-    intelDRI2FlushInvalidate,
+    intelDRI2Invalidate,
 };
 
 static const __DRIextension *intelScreenExtensions[] = {
diff --git a/src/mesa/drivers/dri/intel/intel_tex_image.c b/src/mesa/drivers/dri/intel/intel_tex_image.c
index d63292edd3..bc4e5c6136 100644
--- a/src/mesa/drivers/dri/intel/intel_tex_image.c
+++ b/src/mesa/drivers/dri/intel/intel_tex_image.c
@@ -748,7 +748,7 @@ intelSetTexBuffer2(__DRIcontext *pDRICtx, GLint target,
    if (!intelObj)
       return;
 
-   if (!dPriv->validBuffers)
+   if (dPriv->lastStamp != *dPriv->pStamp)
       intel_update_renderbuffers(pDRICtx, dPriv);
 
    rb = intel_get_renderbuffer(fb, BUFFER_FRONT_LEFT);