Add an option to EXA for the DDX to request that EXA hide the pixmap's

    devPrivate.ptr when pointing at offscreen memory, outside of
    exaPrepare/FinishAccess(). This was used with fakexa to find (by NULL
    dereference) many instances of un-Prepared CPU access to the
    framebuffer:
- GC tiles used in several ops when fillStyle == FillTiled were never
    Prepared.
- Migration could lead to un-Prepared access to mask data in render's
    Trapezoids and Triangles
- PutImage's UploadToScreen failure fallback failed to Prepare.

1 files changed, 7 insertions, 4 deletions

diff --git a/exa/exa_migration.c b/exa/exa_migration.c
index e7c180219..50700ed46 100644
--- a/exa/exa_migration.c
+++ b/exa/exa_migration.c
@@ -190,7 +190,7 @@ exaPixmapSave (ScreenPtr pScreen, ExaOffscreenArea *area)
 		  pPixmap->drawable.width,
 		  pPixmap->drawable.height));
 
-    if (pPixmap->devPrivate.ptr == pExaPixmap->fb_ptr) {
+    if (exaPixmapIsOffscreen(pPixmap)) {
 	exaCopyDirtyToSys (pPixmap);
 	pPixmap->devPrivate.ptr = pExaPixmap->sys_ptr;
 	pPixmap->devKind = pExaPixmap->sys_pitch;
@@ -233,7 +233,7 @@ exaMoveInPixmap (PixmapPtr pPixmap)
 	return;
 
     /* If we're already in FB, our work is done. */
-    if (pPixmap->devPrivate.ptr == pExaPixmap->fb_ptr)
+    if (exaPixmapIsOffscreen(pPixmap))
 	return;
 
     /* If we're not allowed to move, then fail. */
@@ -267,7 +267,10 @@ exaMoveInPixmap (PixmapPtr pPixmap)
 
     exaCopyDirtyToFb (pPixmap);
 
-    pPixmap->devPrivate.ptr = (pointer) pExaPixmap->fb_ptr;
+    if (pExaScr->hideOffscreenPixmapData)
+	pPixmap->devPrivate.ptr = NULL;
+    else
+	pPixmap->devPrivate.ptr = pExaPixmap->fb_ptr;
     pPixmap->devKind = pExaPixmap->fb_pitch;
     pPixmap->drawable.serialNumber = NEXT_SERIAL_NUMBER;
 }
@@ -291,7 +294,7 @@ exaMoveOutPixmap (PixmapPtr pPixmap)
 		  pPixmap->drawable.width,
 		  pPixmap->drawable.height));
 
-    if (pPixmap->devPrivate.ptr == pExaPixmap->fb_ptr) {
+    if (exaPixmapIsOffscreen(pPixmap)) {
 	exaCopyDirtyToSys (pPixmap);
 
 	pPixmap->devPrivate.ptr = pExaPixmap->sys_ptr;