[PATCH] DRI2: use ConfigNotify to re-allocate buffers if root window changes

[Jesse Barnes]

Ok, back to tracking serials then.

Unfortunately, using the pixmap serial for windows doesn't actually fix
this bug.  See below, maybe something is wrong with my
DRI2DrawableSerial function.  Using the drawable serial unconditionally
lets things work (just like the old patch).

-- 
Jesse Barnes, Intel Open Source Technology Center

diff --git a/hw/xfree86/dri2/dri2.c b/hw/xfree86/dri2/dri2.c
index f9ba8e7..34f735f 100644
--- a/hw/xfree86/dri2/dri2.c
+++ b/hw/xfree86/dri2/dri2.c
@@ -82,6 +82,7 @@ typedef struct _DRI2Drawable {
     CARD64		 last_swap_msc; /* msc at completion of most recent swap */
     CARD64		 last_swap_ust; /* ust at completion of most recent swap */
     int			 swap_limit; /* for N-buffering */
+    unsigned long	 serialNumber;
 } DRI2DrawableRec, *DRI2DrawablePtr;
 
 typedef struct _DRI2Screen {
@@ -130,6 +131,19 @@ DRI2GetDrawable(DrawablePtr pDraw)
     }
 }
 
+static unsigned long
+DRI2DrawableSerial(DrawablePtr pDraw)
+{
+    ScreenPtr pScreen = pDraw->pScreen;
+    PixmapPtr pPix;
+
+    if (pDraw->type != DRAWABLE_WINDOW)
+	return pDraw->serialNumber;
+
+    pPix = pScreen->GetWindowPixmap((WindowPtr)pDraw);
+    return pPix->drawable.serialNumber;
+}
+
 static DRI2DrawablePtr
 DRI2AllocateDrawable(DrawablePtr pDraw)
 {
@@ -163,6 +177,7 @@ DRI2AllocateDrawable(DrawablePtr pDraw)
     pPriv->last_swap_msc = 0;
     pPriv->last_swap_ust = 0;
     list_init(&pPriv->reference_list);
+    pPriv->serialNumber = DRI2DrawableSerial(pDraw);
 
     if (pDraw->type == DRAWABLE_WINDOW) {
 	pWin = (WindowPtr) pDraw;
@@ -326,6 +341,7 @@ allocate_or_reuse_buffer(DrawablePtr pDraw, DRI2ScreenPtr ds,
 	|| !dimensions_match
 	|| (pPriv->buffers[old_buf]->format != format)) {
 	*buffer = (*ds->CreateBuffer)(pDraw, attachment, format);
+	pPriv->serialNumber = DRI2DrawableSerial(pDraw);
 	return TRUE;
 
     } else {
@@ -384,7 +400,8 @@ do_get_buffers(DrawablePtr pDraw, int *width, int *height,
     }
 
     dimensions_match = (pDraw->width == pPriv->width)
-	&& (pDraw->height == pPriv->height);
+	&& (pDraw->height == pPriv->height)
+	&& (pPriv->serialNumber == DRI2DrawableSerial(pDraw));
 
     buffers = malloc((count + 1) * sizeof(buffers[0]));