EXA: Try to minimize UploadToScreen calls for mixed pixmaps.

If there are several software fallbacks affecting the system memory copy of the
same pixmap, only copy the results back to the driver pixmap when it's used for
acceleration again, or in the BlockHandler, whichever happens first.

exa/exa.c

@@ -774,10 +774,18 @@ ExaBlockHandler(int screenNum, pointer blockData, pointer pTimeout,
     ScreenPtr pScreen = screenInfo.screens[screenNum];
     ExaScreenPriv(pScreen);
 
+    /* Move any deferred results from a software fallback to the driver pixmap */
+    if (pExaScr->deferred_mixed_pixmap)
+	exaMoveInPixmap_mixed(pExaScr->deferred_mixed_pixmap);
+
     unwrap(pExaScr, pScreen, BlockHandler);
     (*pScreen->BlockHandler) (screenNum, blockData, pTimeout, pReadmask);
     wrap(pExaScr, pScreen, BlockHandler, ExaBlockHandler);
 
+    /* The rest only applies to classic EXA */
+    if (pExaScr->info->flags & EXA_HANDLES_PIXMAPS)
+	return;
+
     /* Try and keep the offscreen memory area tidy every now and then (at most 
      * once per second) when the server has been idle for at least 100ms.
      */
@@ -991,10 +999,12 @@ exaDriverInit (ScreenPtr		pScreen,
      * Replace various fb screen functions
      */
     if ((pExaScr->info->flags & EXA_OFFSCREEN_PIXMAPS) &&
-	!(pExaScr->info->flags & EXA_HANDLES_PIXMAPS)) {
+	(!(pExaScr->info->flags & EXA_HANDLES_PIXMAPS) ||
+	 (pExaScr->info->flags & EXA_MIXED_PIXMAPS)))
 	wrap(pExaScr, pScreen, BlockHandler, ExaBlockHandler);
+    if ((pExaScr->info->flags & EXA_OFFSCREEN_PIXMAPS) &&
+	!(pExaScr->info->flags & EXA_HANDLES_PIXMAPS))
 	wrap(pExaScr, pScreen, WakeupHandler, ExaWakeupHandler);
-    }
     wrap(pExaScr, pScreen, CreateGC, exaCreateGC);
     wrap(pExaScr, pScreen, CloseScreen, exaCloseScreen);
     wrap(pExaScr, pScreen, GetImage, exaGetImage);

exa/exa_migration_mixed.c

@@ -99,8 +99,13 @@ exaDoMigration_mixed(ExaMigrationPtr pixmaps, int npixmaps, Bool can_accel)
 	    exaCreateDriverPixmap_mixed(pPixmap);
 
 	if (pExaPixmap->pDamage && exaPixmapIsOffscreen(pPixmap)) {
+	    ExaScreenPriv(pPixmap->drawable.pScreen);
+
 	    pPixmap->devKind = pExaPixmap->fb_pitch;
 	    exaCopyDirtyToFb(pixmaps + i);
+
+	    if (pExaScr->deferred_mixed_pixmap == pPixmap)
+		pExaScr->deferred_mixed_pixmap = NULL;
 	}
 
 	pExaPixmap->offscreen = exaPixmapIsOffscreen(pPixmap);
@@ -197,6 +202,9 @@ exaPrepareAccessReg_mixed(PixmapPtr pPixmap, int index, RegionPtr pReg)
 
 /* Move back results of software rendering on system memory copy of mixed driver
  * pixmap (see exaPrepareAccessReg_mixed).
+ *
+ * Defer moving the destination back into the driver pixmap, to try and save
+ * overhead on multiple consequent software fallbacks.
  */
 void exaFinishAccess_mixed(PixmapPtr pPixmap, int index)
 {
@@ -204,6 +212,16 @@ void exaFinishAccess_mixed(PixmapPtr pPixmap, int index)
 
     if (pExaPixmap->pDamage && exaPixmapIsOffscreen(pPixmap)) {
 	DamageRegionProcessPending(&pPixmap->drawable);
-	exaMoveInPixmap_mixed(pPixmap);
+
+	if (index == EXA_PREPARE_DEST || index == EXA_PREPARE_AUX_DEST) {
+	    ExaScreenPriv(pPixmap->drawable.pScreen);
+
+	    if (pExaScr->deferred_mixed_pixmap &&
+		pExaScr->deferred_mixed_pixmap != pPixmap)
+		exaMoveInPixmap_mixed(pExaScr->deferred_mixed_pixmap);
+	    pExaScr->deferred_mixed_pixmap = pPixmap;
+	    pPixmap->devKind = pExaPixmap->fb_pitch;
+	} else
+	    exaMoveInPixmap_mixed(pPixmap);
     }
 }

exa/exa_mixed.c

@@ -192,6 +192,9 @@ exaDestroyPixmap_mixed(PixmapPtr pPixmap)
     {
 	ExaPixmapPriv (pPixmap);
 
+	if (pExaScr->deferred_mixed_pixmap == pPixmap)
+	    pExaScr->deferred_mixed_pixmap = NULL;
+
 	if (pExaPixmap->driverPriv)
 	    pExaScr->info->DestroyPixmap(pScreen, pExaPixmap->driverPriv);
 	pExaPixmap->driverPriv = NULL;

exa/exa_priv.h

@@ -188,6 +188,7 @@ typedef struct {
     unsigned			 numOffscreenAvailable;
     CARD32			 lastDefragment;
     CARD32			 nextDefragment;
+    PixmapPtr			 deferred_mixed_pixmap;
 
     /* Reference counting for accessed pixmaps */
     struct {