[PATCH 3/4] dri2: Only re-create the FrontBuffer after the WindowPixmap is updated

[Chris Wilson]

If the drawable size remained the same, the application can continue to
reuse the same back and auxiliary buffers, but will need the new name
for the Pixmap.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala at nokia.com>
Cc: Dave Airlie <airlied at redhat.com>
Cc: Kristian Høgsberg <krh at bitplanet.net>
Cc: Jesse Barnes <jbarnes at virtuousgeek.org>
Cc: Michel Dänzer <michel at daenzer.net>
---
 hw/xfree86/dri2/dri2.c |   35 ++++++++++++++++++++---------------
 1 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/hw/xfree86/dri2/dri2.c b/hw/xfree86/dri2/dri2.c
index d837852..7896a61 100644
--- a/hw/xfree86/dri2/dri2.c
+++ b/hw/xfree86/dri2/dri2.c
@@ -340,13 +340,13 @@ static Bool
 allocate_or_reuse_buffer(DrawablePtr pDraw, DRI2ScreenPtr ds,
 			 DRI2DrawablePtr pPriv,
 			 unsigned int attachment, unsigned int format,
-			 int dimensions_match, DRI2BufferPtr *buffer)
+			 int force, DRI2BufferPtr *buffer)
 {
-    int old_buf = find_attachment(pPriv, attachment);
+    int old_buf;
 
-    if ((old_buf < 0)
-	|| !dimensions_match
-	|| (pPriv->buffers[old_buf]->format != format)) {
+    if (force ||
+	(old_buf = find_attachment(pPriv, attachment)) < 0 ||
+	(pPriv->buffers[old_buf]->format != format)) {
 	*buffer = (*ds->CreateBuffer)(pDraw, attachment, format);
 	pPriv->serialNumber = DRI2DrawableSerial(pDraw);
 	return TRUE;
@@ -395,7 +395,7 @@ do_get_buffers(DrawablePtr pDraw, int *width, int *height,
     int need_fake_front = 0;
     int have_fake_front = 0;
     int front_format = 0;
-    int dimensions_match;
+    int dimensions_mismatch;
     int buffers_changed = 0;
     int i;
 
@@ -406,9 +406,9 @@ do_get_buffers(DrawablePtr pDraw, int *width, int *height,
 	return NULL;
     }
 
-    dimensions_match = (pDraw->width == pPriv->width)
-	&& (pDraw->height == pPriv->height)
-	&& (pPriv->serialNumber == DRI2DrawableSerial(pDraw));
+    dimensions_mismatch =
+	    pDraw->width != pPriv->width ||
+	    pDraw->height != pPriv->height;
 
     buffers = calloc((count + 1), sizeof(buffers[0]));
     if (!buffers)
@@ -417,10 +417,13 @@ do_get_buffers(DrawablePtr pDraw, int *width, int *height,
     for (i = 0; i < count; i++) {
 	const unsigned attachment = *(attachments++);
 	const unsigned format = (has_format) ? *(attachments++) : 0;
+	int force = dimensions_mismatch;
+
+	if (attachment == DRI2BufferFrontLeft)
+		force |= pPriv->serialNumber != DRI2DrawableSerial(pDraw);
 
 	if (allocate_or_reuse_buffer(pDraw, ds, pPriv, attachment,
-				     format, dimensions_match,
-				     &buffers[i]))
+				     format, force, &buffers[i]))
 		buffers_changed = 1;
 
 	if (buffers[i] == NULL)
@@ -455,7 +458,9 @@ do_get_buffers(DrawablePtr pDraw, int *width, int *height,
 
     if (need_real_front > 0) {
 	if (allocate_or_reuse_buffer(pDraw, ds, pPriv, DRI2BufferFrontLeft,
-				     front_format, dimensions_match,
+				     front_format,
+				     dimensions_mismatch ||
+				     pPriv->serialNumber != DRI2DrawableSerial(pDraw),
 				     &buffers[i]))
 	    buffers_changed = 1;
 
@@ -466,7 +471,7 @@ do_get_buffers(DrawablePtr pDraw, int *width, int *height,
 
     if (need_fake_front > 0) {
 	if (allocate_or_reuse_buffer(pDraw, ds, pPriv, DRI2BufferFakeFrontLeft,
-				     front_format, dimensions_match,
+				     front_format, dimensions_mismatch,
 				     &buffers[i]))
 	    buffers_changed = 1;
 
@@ -495,8 +500,8 @@ do_get_buffers(DrawablePtr pDraw, int *width, int *height,
 	box.y2 = pPriv->height;
 	RegionInit(&region, &box, 0);
 
-	DRI2CopyRegion(pDraw, &region, DRI2BufferFakeFrontLeft,
-		       DRI2BufferFrontLeft);
+	DRI2CopyRegion(pDraw, &region,
+		       DRI2BufferFakeFrontLeft, DRI2BufferFrontLeft);
     }
 
     pPriv->needInvalidate = TRUE;
-- 
1.7.5.1