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>

3 files changed, 5 insertions, 8 deletions

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);