EXA: Handle separate alpha maps properly in Composite fallback.

Fixes https://bugs.freedesktop.org/show_bug.cgi?id=18710 .

As this can't work without new EXA_PREPARE_AUX* indices, this requires a major
version bump, so we can also drop the UploadToScratch driver hook and
ExaOffscreenSwap*(). So this also fixes
http://bugs.freedesktop.org/show_bug.cgi?id=20213 .

Moreover, introduce EXA_DRIVER_KNOWN_MAJOR to break compilation of drivers
which may not be able to handle EXA_PREPARE_AUX*, giving instructions how to
make them build again in the #error message.

Signed-off-by: Michel Dänzer <daenzer@vmware.com>

6 files changed, 45 insertions, 108 deletions

diff --git a/exa/Makefile.am b/exa/Makefile.am
index 2b3f1e416..7065e197d 100644
--- a/exa/Makefile.am
+++ b/exa/Makefile.am
@@ -12,7 +12,8 @@ INCLUDES = \
 	$(XORG_INCS) \
 	-I$(srcdir)/../miext/cw
 
-AM_CFLAGS = $(XORG_CFLAGS) $(DIX_CFLAGS)
+# Use an arbitrary high major version here to satisfy any driver checks in exa.h
+AM_CFLAGS = $(XORG_CFLAGS) $(DIX_CFLAGS) -DEXA_DRIVER_KNOWN_MAJOR=99
 
 libexa_la_SOURCES = \
 	exa.c \
diff --git a/exa/exa.h b/exa/exa.h
index 21a0f1abf..b80d0d4a2 100644
--- a/exa/exa.h
+++ b/exa/exa.h
@@ -38,8 +38,17 @@
 #include "picturestr.h"
 #include "fb.h"
 
-#define EXA_VERSION_MAJOR   2
-#define EXA_VERSION_MINOR   4
+/* If the driver can't seem to handle this major version, abort compilation with
+ * instructions how to fix it.
+ */
+#if !defined(EXA_DRIVER_KNOWN_MAJOR) || EXA_DRIVER_KNOWN_MAJOR < 3
+#error Make sure this EXA driver either does not have Prepare/FinishAccess \
+    hooks or that they can handle EXA_PREPARE_AUX*, and	\
+    #define EXA_DRIVER_KNOWN_MAJOR 3 before including exa.h
+#endif
+
+#define EXA_VERSION_MAJOR   3
+#define EXA_VERSION_MINOR   0
 #define EXA_VERSION_RELEASE 0
 
 typedef struct _ExaOffscreenArea ExaOffscreenArea;
@@ -499,32 +508,6 @@ typedef struct _ExaDriver {
                                    int                  src_pitch);
 
     /**
-     * UploadToScratch() is used to upload a pixmap to a scratch area for
-     * acceleration.
-     *
-     * @param pSrc source pixmap in host memory
-     * @param pDst fake, scratch pixmap to be set up in offscreen memory.
-     *
-     * The UploadToScratch() call was added to support Xati before Xati had
-     * support for hostdata uploads and before exaGlyphs() was written.  It
-     * behaves incorrectly (uses an invalid pixmap as pDst),
-     * and UploadToScreen() should be implemented instead.
-     *
-     * Drivers implementing UploadToScratch() had to set up space (likely in a
-     * statically allocated area) in offscreen memory, copy pSrc to that
-     * scratch area, and adust pDst->devKind for the pitch and
-     * pDst->devPrivate.ptr for the pointer to that scratch area.  The driver
-     * was responsible for syncing (as it was implemented using memcpy() in
-     * Xati), and only the data from the last UploadToScratch() was guaranteed
-     * to be valid at any given time.
-     *
-     * UploadToScratch() should not be implemented by drivers, and will likely
-     * be removed in a future version of EXA.
-     */
-    Bool        (*UploadToScratch) (PixmapPtr           pSrc,
-                                    PixmapPtr           pDst);
-
-    /**
      * DownloadFromScreen() loads a rectangle of data from pSrc into dst
      *
      * @param pSrc source pixmap
@@ -672,6 +655,13 @@ typedef struct _ExaDriver {
 	 * from.
 	 */
 	#define EXA_PREPARE_MASK	2
+	/**
+	 * EXA_PREPARE_AUX* are additional indices for other purposes, e.g.
+	 * separate alpha maps with Composite operations.
+	 */
+	#define EXA_PREPARE_AUX0	3
+	#define EXA_PREPARE_AUX1	4
+	#define EXA_PREPARE_AUX2	5
 	/** @} */
 
     /**
diff --git a/exa/exa_offscreen.c b/exa/exa_offscreen.c
index 4aaa2c132..c45df6711 100644
--- a/exa/exa_offscreen.c
+++ b/exa/exa_offscreen.c
@@ -285,36 +285,6 @@ exaOffscreenAlloc (ScreenPtr pScreen, int size, int align,
     return area;
 }
 
-/**
- * Ejects all offscreen areas, and uninitializes the offscreen memory manager.
- */
-void
-ExaOffscreenSwapOut (ScreenPtr pScreen)
-{
-    ExaScreenPriv (pScreen);
-
-    ExaOffscreenValidate (pScreen);
-    /* loop until a single free area spans the space */
-    for (;;)
-    {
-	ExaOffscreenArea *area = pExaScr->info->offScreenAreas;
-
-	if (!area)
-	    break;
-	if (area->state == ExaOffscreenAvail)
-	{
-	    area = area->next;
-	    if (!area)
-		break;
-	}
-	assert (area->state != ExaOffscreenAvail);
-	(void) ExaOffscreenKickOut (pScreen, area);
-	ExaOffscreenValidate (pScreen);
-    }
-    ExaOffscreenValidate (pScreen);
-    ExaOffscreenFini (pScreen);
-}
-
 /** Ejects all pixmaps managed by EXA. */
 static void
 ExaOffscreenEjectPixmaps (ScreenPtr pScreen)
@@ -344,26 +314,14 @@ ExaOffscreenEjectPixmaps (ScreenPtr pScreen)
     ExaOffscreenValidate (pScreen);
 }
 
-void
-ExaOffscreenSwapIn (ScreenPtr pScreen)
-{
-    exaOffscreenInit (pScreen);
-}
-
 /**
  * Prepares EXA for disabling of FB access, or restoring it.
  *
- * In version 2.1, the disabling results in pixmaps being ejected, while other
- * allocations remain.  With this plus the prevention of migration while
- * swappedOut is set, EXA by itself should not cause any access of the
- * framebuffer to occur while swapped out.  Any remaining issues are the
- * responsibility of the driver.
- *
- * Prior to version 2.1, all allocations, including locked ones, are ejected
- * when access is disabled, and the allocator is torn down while swappedOut
- * is set.  This is more drastic, and caused implementation difficulties for
- * many drivers that could otherwise handle the lack of FB access while
- * swapped out.
+ * The disabling results in pixmaps being ejected, while other allocations
+ * remain.  With this plus the prevention of migration while swappedOut is
+ * set, EXA by itself should not cause any access of the framebuffer to occur
+ * while swapped out.  Any remaining issues are the responsibility of the
+ * driver.
  */
 void
 exaEnableDisableFBAccess (int index, Bool enable)
@@ -372,16 +330,11 @@ exaEnableDisableFBAccess (int index, Bool enable)
     ExaScreenPriv (pScreen);
 
     if (!enable && pExaScr->disableFbCount++ == 0) {
-	if (pExaScr->info->exa_minor < 1)
-	    ExaOffscreenSwapOut (pScreen);
-	else
-	    ExaOffscreenEjectPixmaps (pScreen);
+	ExaOffscreenEjectPixmaps (pScreen);
 	pExaScr->swappedOut = TRUE;
     }
     
     if (enable && --pExaScr->disableFbCount == 0) {
-	if (pExaScr->info->exa_minor < 1)
-	    ExaOffscreenSwapIn (pScreen);
 	pExaScr->swappedOut = FALSE;
     }
 }
diff --git a/exa/exa_priv.h b/exa/exa_priv.h
index 461e5e37f..ea8c3da91 100644
--- a/exa/exa_priv.h
+++ b/exa/exa_priv.h
@@ -433,12 +433,6 @@ ExaCheckComposite (CARD8      op,
 #endif
 
 /* exa_offscreen.c */
-void
-ExaOffscreenSwapOut (ScreenPtr pScreen);
-
-void
-ExaOffscreenSwapIn (ScreenPtr pScreen);
-
 Bool
 exaOffscreenInit(ScreenPtr pScreen);
 
diff --git a/exa/exa_render.c b/exa/exa_render.c
index 17885317f..bdc1ed195 100644
--- a/exa/exa_render.c
+++ b/exa/exa_render.c
@@ -342,7 +342,6 @@ exaTryDriverCompositeRects(CARD8	       op,
     int src_off_x, src_off_y, dst_off_x, dst_off_y;
     PixmapPtr pSrcPix, pDstPix;
     ExaPixmapPrivPtr pSrcExaPix, pDstExaPix;
-    struct _Pixmap scratch;
     ExaMigrationRec pixmaps[2];
 
     if (!pExaScr->info->PrepareComposite)
@@ -386,13 +385,6 @@ exaTryDriverCompositeRects(CARD8	       op,
     if (!exaPixmapIsOffscreen(pDstPix))
 	return 0;
     
-    if (!pSrcPix && pExaScr->info->UploadToScratch)
-    {
-	pSrcPix = exaGetDrawablePixmap (pSrc->pDrawable);
-	if ((*pExaScr->info->UploadToScratch) (pSrcPix, &scratch))
-	    pSrcPix = &scratch;
-    }
-
     if (!pSrcPix)
 	return 0;
 
@@ -573,7 +565,6 @@ exaTryDriverComposite(CARD8		op,
     int src_off_x, src_off_y, mask_off_x, mask_off_y, dst_off_x, dst_off_y;
     PixmapPtr pSrcPix, pMaskPix = NULL, pDstPix;
     ExaPixmapPrivPtr pSrcExaPix, pMaskExaPix = NULL, pDstExaPix;
-    struct _Pixmap scratch;
     ExaMigrationRec pixmaps[3];
 
     pSrcPix = exaGetDrawablePixmap(pSrc->pDrawable);
@@ -652,16 +643,6 @@ exaTryDriverComposite(CARD8		op,
 	return 0;
     }
 
-    if (!pSrcPix && (!pMask || pMaskPix) && pExaScr->info->UploadToScratch) {
-	pSrcPix = exaGetDrawablePixmap (pSrc->pDrawable);
-	if ((*pExaScr->info->UploadToScratch) (pSrcPix, &scratch))
-	    pSrcPix = &scratch;
-    } else if (pSrcPix && pMask && !pMaskPix && pExaScr->info->UploadToScratch) {
-	pMaskPix = exaGetDrawablePixmap (pMask->pDrawable);
-	if ((*pExaScr->info->UploadToScratch) (pMaskPix, &scratch))
-	    pMaskPix = &scratch;
-    }
-
     if (!pSrcPix || (pMask && !pMaskPix)) {
 	REGION_UNINIT(pDst->pDrawable->pScreen, &region);
 	return 0;
diff --git a/exa/exa_unaccel.c b/exa/exa_unaccel.c
index c821f0da8..0c4319f5a 100644
--- a/exa/exa_unaccel.c
+++ b/exa/exa_unaccel.c
@@ -405,16 +405,28 @@ ExaCheckComposite (CARD8      op,
 	REGION_TRANSLATE(pScreen, &region, xoff, yoff);
 
 	exaPrepareAccessReg (pDst->pDrawable, EXA_PREPARE_DEST, &region);
-    } else
+
+	if (pDst->alphaMap && pDst->alphaMap->pDrawable)
+	    exaPrepareAccessReg(pDst->alphaMap->pDrawable, EXA_PREPARE_AUX0,
+				&region);
+    } else {
 	exaPrepareAccess (pDst->pDrawable, EXA_PREPARE_DEST);
 
+	if (pDst->alphaMap && pDst->alphaMap->pDrawable)
+	    exaPrepareAccess(pDst->alphaMap->pDrawable, EXA_PREPARE_AUX0);
+    }
+
     EXA_FALLBACK(("from picts %p/%p to pict %p\n",
 		 pSrc, pMask, pDst));
 
     if (pSrc->pDrawable != NULL)
 	exaPrepareAccess (pSrc->pDrawable, EXA_PREPARE_SRC);
+    if (pSrc->alphaMap && pSrc->alphaMap->pDrawable)
+	exaPrepareAccess(pSrc->alphaMap->pDrawable, EXA_PREPARE_AUX2);
     if (pMask && pMask->pDrawable != NULL)
 	exaPrepareAccess (pMask->pDrawable, EXA_PREPARE_MASK);
+    if (pMask && pMask->alphaMap && pMask->alphaMap->pDrawable)
+	exaPrepareAccess(pMask->alphaMap->pDrawable, EXA_PREPARE_AUX1);
 #ifdef RENDER
     swap(pExaScr, ps, Composite);
     ps->Composite (op,
@@ -433,9 +445,15 @@ ExaCheckComposite (CARD8      op,
 #endif /* RENDER */
     if (pMask && pMask->pDrawable != NULL)
 	exaFinishAccess (pMask->pDrawable, EXA_PREPARE_MASK);
+    if (pMask && pMask->alphaMap && pMask->alphaMap->pDrawable)
+	exaFinishAccess(pMask->alphaMap->pDrawable, EXA_PREPARE_AUX1);
     if (pSrc->pDrawable != NULL)
 	exaFinishAccess (pSrc->pDrawable, EXA_PREPARE_SRC);
+    if (pSrc->alphaMap && pSrc->alphaMap->pDrawable)
+	exaFinishAccess(pSrc->alphaMap->pDrawable, EXA_PREPARE_AUX2);
     exaFinishAccess (pDst->pDrawable, EXA_PREPARE_DEST);
+    if (pDst->alphaMap && pDst->alphaMap->pDrawable)
+	exaFinishAccess(pDst->alphaMap->pDrawable, EXA_PREPARE_AUX0);
 
     REGION_UNINIT(pScreen, &region);
 }