[PATCH] exa: fix ExaCheckCopyNtoN for exa_classic when source = dest

[Éric Piel]

Hello,

This patch originally written by Yves fixes this bug:
https://bugs.freedesktop.org/show_bug.cgi?id=28077

Could someone review and apply it?

Yves, don't hesitate to add your "Signed-off-by".
Cheers,
Eric


From f958be1d48b7a75a4044a3db8a2b25c7c44662a3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89ric=20Piel?= <eric.p...@tremplin-utc.net>
Date: Thu, 10 Jun 2010 19:53:25 +0200
Subject: [PATCH] exa: fix ExaCheckCopyNtoN for exa_classic when source = dest
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From: Yves De Muyter <y...@connected.be>
In case you want to copy a region with source = dest, you have the same pixmap
as source and dest.

At the end of exaPixmapIsOffscreen_classic() the devPrivate.ptr is reset to
NULL (look at the sources).

Now this is what happens in ExaCheckCopyNtoN:

exaPrepareAccess( pDst );
   Calls IsOffscreen()
      sets devPrivate.ptr to NULL
   sets up devPrivate.ptr to real pointer
   Everything OK
exaPrepareAccess( pSrc );
   Calls IsOffscreen()
      sets devPrivate.ptr to NULL
   BAILS OUT CAUSE OF NESTED OPERATION SINCE DST EQUALS SRC

We end up with devPrivate.ptr as NULL, and that is clearly wrong.

In particular this fixes a segfault when using the psb driver (bug 28077)

Signed-off-by: Éric Piel <eric.p...@tremplin-utc.net>
---
 exa/exa_classic.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/exa/exa_classic.c b/exa/exa_classic.c
index 12f3987..28cc421 100644
--- a/exa/exa_classic.c
+++ b/exa/exa_classic.c
@@ -256,9 +256,10 @@ exaPixmapIsOffscreen_classic(PixmapPtr pPixmap)
     Bool ret;
 
     if (pExaScr->info->PixmapIsOffscreen) {
+       void* old_ptr = pPixmap->devPrivate.ptr;
        pPixmap->devPrivate.ptr = ExaGetPixmapAddress(pPixmap);
        ret = pExaScr->info->PixmapIsOffscreen(pPixmap);
-       pPixmap->devPrivate.ptr = NULL;
+       pPixmap->devPrivate.ptr = old_ptr;
     } else
        ret = (pExaPixmap->offscreen && pExaPixmap->fb_ptr);
 
-- 
1.7.1


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