armsoc: rough patch to make flippable state transition handling independent of serial number (DRI2 no longer looks at this)

gistfile1.diff

diff --git a/src/armsoc_dri2.c b/src/armsoc_dri2.c
index f69dbe8..e82bb64 100644
--- a/src/armsoc_dri2.c
+++ b/src/armsoc_dri2.c
@@ -626,26 +626,30 @@ ARMSOCDRI2ScheduleSwap(ClientPtr client, DrawablePtr pDraw,
 	src_bo = boFromBuffer(pSrcBuffer);
 	dst_bo = boFromBuffer(pDstBuffer);
 
-	src_fb_id = armsoc_bo_get_fb(src_bo);
-	dst_fb_id = armsoc_bo_get_fb(dst_bo);
-
 	new_canflip = canflip(pDraw);
 	if ((src->previous_canflip != new_canflip) ||
 	    (dst->previous_canflip != new_canflip)) {
 		/* The drawable has transitioned between being flippable and
-		 * non-flippable or vice versa. Bump the serial number to force
-		 * the DRI2 buffers to be re-allocated during the next frame so
-		 * that:
-		 * - It is able to be scanned out
-		 *        (if drawable is now flippable), or
-		 * - It is not taking up possibly scarce scanout-able memory
-		 *        (if drawable is now not flippable)
+		 * non-flippable or vice versa. Add a framebuffer if desired,
+		 * or remove the one it has in order to save potentially
+		 * scarce scanout memory.
 		 */
-
-		PixmapPtr pPix = pScreen->GetWindowPixmap((WindowPtr)pDraw);
-		pPix->drawable.serialNumber = NEXT_SERIAL_NUMBER;
+		if (new_canflip) {
+			if (armsoc_bo_get_fb(src_bo) == 0)
+				armsoc_bo_add_fb(src_bo);
+			if (armsoc_bo_get_fb(dst_bo) == 0)
+				armsoc_bo_add_fb(dst_bo);
+		} else {
+			if (armsoc_bo_get_fb(src_bo) != 0)
+				armsoc_bo_rm_fb(src_bo);
+			if (armsoc_bo_get_fb(dst_bo) != 0)
+				armsoc_bo_rm_fb(dst_bo);
+		}
 	}
 
+	src_fb_id = armsoc_bo_get_fb(src_bo);
+	dst_fb_id = armsoc_bo_get_fb(dst_bo);
+
 	src->previous_canflip = new_canflip;
 	dst->previous_canflip = new_canflip;