diff --git a/exa/exa.c b/exa/exa.c
index 81dc3e2ab..0e3ea7036 100644
--- a/exa/exa.c
+++ b/exa/exa.c
@@ -248,6 +248,19 @@ exaSetAccelBlock(ExaScreenPrivPtr pExaScr, ExaPixmapPrivPtr pExaPixmap,
         pExaPixmap->accel_blocked |= EXA_RANGE_HEIGHT;
 }
 
+static void
+exaSetFbPitch(ExaScreenPrivPtr pExaScr, ExaPixmapPrivPtr pExaPixmap,
+              int w, int h, int bpp)
+{
+    if (pExaScr->info->flags & EXA_OFFSCREEN_ALIGN_POT && w != 1)
+        pExaPixmap->fb_pitch = (1 << (exaLog2(w - 1) + 1)) * bpp / 8;
+    else
+        pExaPixmap->fb_pitch = w * bpp / 8;
+
+    pExaPixmap->fb_pitch = EXA_ALIGN(pExaPixmap->fb_pitch,
+                                     pExaScr->info->pixmapPitchAlign);
+}
+
 /**
  * exaCreatePixmap() creates a new pixmap.
  *
@@ -292,12 +305,8 @@ exaCreatePixmap(ScreenPtr pScreen, int w, int h, int depth,
         if (paddedWidth / 4 > 32767 || h > 32767)
             return NullPixmap;
 
-        if (pExaScr->info->flags & EXA_OFFSCREEN_ALIGN_POT && w != 1)
-            pExaPixmap->fb_pitch = (1 << (exaLog2(w - 1) + 1)) * bpp / 8;
-        else
-            pExaPixmap->fb_pitch = w * bpp / 8;
-        pExaPixmap->fb_pitch = EXA_ALIGN(pExaPixmap->fb_pitch,
-                                         pExaScr->info->pixmapPitchAlign);
+        exaSetFbPitch(pExaScr, pExaPixmap, w, h, bpp);
+
         if (paddedWidth < pExaPixmap->fb_pitch)
             paddedWidth = pExaPixmap->fb_pitch;
 
@@ -331,12 +340,7 @@ exaCreatePixmap(ScreenPtr pScreen, int w, int h, int depth,
         pExaPixmap->offscreen = FALSE;
 
         pExaPixmap->fb_ptr = NULL;
-        if (pExaScr->info->flags & EXA_OFFSCREEN_ALIGN_POT && w != 1)
-            pExaPixmap->fb_pitch = (1 << (exaLog2(w - 1) + 1)) * bpp / 8;
-        else
-            pExaPixmap->fb_pitch = w * bpp / 8;
-        pExaPixmap->fb_pitch = EXA_ALIGN(pExaPixmap->fb_pitch,
-				         pExaScr->info->pixmapPitchAlign);
+        exaSetFbPitch(pExaScr, pExaPixmap, w, h, bpp);
         pExaPixmap->fb_size = pExaPixmap->fb_pitch * h;
 
         if (pExaPixmap->fb_pitch > 131071) {
@@ -384,10 +388,19 @@ exaModifyPixmapHeader(PixmapPtr pPixmap, int width, int height, int depth,
     pExaPixmap = ExaGetPixmapPriv(pPixmap);
 
     if (pExaPixmap) {
-	pExaPixmap->sys_ptr = pPixData;
+        if (pPixData)
+            pExaPixmap->sys_ptr = pPixData;
 
-        exaSetAccelBlock(pExaScr, pExaPixmap,
-                         width, height, bitsPerPixel);
+        if (devKind > 0)
+            pExaPixmap->sys_pitch = devKind;
+
+        if (width > 0 && height > 0 && bitsPerPixel > 0) {
+            exaSetFbPitch(pExaScr, pExaPixmap,
+                          width, height, bitsPerPixel);
+
+            exaSetAccelBlock(pExaScr, pExaPixmap,
+                             width, height, bitsPerPixel);
+        }
     }