exa: add hooks for drivers to take over pixmap allocation

This adds hooks for the driver to access Create/DestroyPixmap and ModifyPixmapHe
ader.

It allocates a 0 sized pixmap using fb and calls the driver routine to do
work of allocating the actual memory.

ModifyPixmapHeader is mainly required for hooking the screen pixmap which
isn't create by normal methods

exa/exa.c

@@ -183,9 +183,18 @@ exaPixmapDirty (PixmapPtr pPix, int x1, int y1, int x2, int y2)
 static Bool
 exaDestroyPixmap (PixmapPtr pPixmap)
 {
+    ScreenPtr	pScreen = pPixmap->drawable.pScreen;
+    ExaScreenPriv(pScreen);
+
     if (pPixmap->refcnt == 1)
     {
 	ExaPixmapPriv (pPixmap);
+
+	if (pExaPixmap->driverPriv) {
+	    pExaScr->info->DestroyPixmap(pScreen, pExaPixmap->driverPriv);
+	    pExaPixmap->driverPriv = NULL;
+	}
+
 	if (pExaPixmap->area)
 	{
 	    DBG_PIXMAP(("-- 0x%p (0x%x) (%dx%d)\n",
@@ -229,47 +238,87 @@ exaCreatePixmap(ScreenPtr pScreen, int w, int h, int depth)
 {
     PixmapPtr		pPixmap;
     ExaPixmapPrivPtr	pExaPixmap;
+    int                 driver_alloc = 0;
     int			bpp;
     ExaScreenPriv(pScreen);
 
     if (w > 32767 || h > 32767)
 	return NullPixmap;
 
-    pPixmap = fbCreatePixmap (pScreen, w, h, depth);
+    if (!pExaScr->info->CreatePixmap) {
+        pPixmap = fbCreatePixmap (pScreen, w, h, depth);
+    } else {
+        driver_alloc = 1;
+        pPixmap = fbCreatePixmap(pScreen, 0, 0, depth);
+    }
+
     if (!pPixmap)
-	return NULL;
+        return NULL;
+
     pExaPixmap = ExaGetPixmapPriv(pPixmap);
 
     bpp = pPixmap->drawable.bitsPerPixel;
 
-    /* Glyphs have w/h equal to zero, and may not be migrated. See exaGlyphs. */
+    if (driver_alloc) {
-    if (!w || !h)
+        size_t paddedWidth, datasize;
-	pExaPixmap->score = EXA_PIXMAP_SCORE_PINNED;
+        void *driver_priv;
-    else
+
-	pExaPixmap->score = EXA_PIXMAP_SCORE_INIT;
+	paddedWidth = ((w * bpp + FB_MASK) >> FB_SHIFT) * sizeof(FbBits);
+        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);
+        if (paddedWidth < pExaPixmap->fb_pitch)
+            paddedWidth = pExaPixmap->fb_pitch;
+
+        datasize = h * paddedWidth;
+
+        driver_priv = pExaScr->info->CreatePixmap(pScreen, datasize, 0);
+        if (!driver_priv) {
+             fbDestroyPixmap(pPixmap);
+             return NULL;
+        }
+
+        (*pScreen->ModifyPixmapHeader)(pPixmap, w, h, 0, 0,
+                                       paddedWidth, NULL);
+         pExaPixmap->driverPriv = driver_priv;
+         pExaPixmap->score = EXA_PIXMAP_SCORE_PINNED;
+    } else {
+         pExaPixmap->driverPriv = NULL;
+         /* Glyphs have w/h equal to zero, and may not be migrated. See exaGlyphs. */
+        if (!w || !h)
+	    pExaPixmap->score = EXA_PIXMAP_SCORE_PINNED;
+        else
+            pExaPixmap->score = EXA_PIXMAP_SCORE_INIT;
+
+        pExaPixmap->sys_ptr = pPixmap->devPrivate.ptr;
+        pExaPixmap->sys_pitch = pPixmap->devKind;
+
+        pPixmap->devPrivate.ptr = NULL;
+        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);
+        pExaPixmap->fb_size = pExaPixmap->fb_pitch * h;
+
+        if (pExaPixmap->fb_pitch > 131071) {
+	     fbDestroyPixmap(pPixmap);
+	     return NULL;
+        }
+    }
  
     pExaPixmap->area = NULL;
 
-    pExaPixmap->sys_ptr = pPixmap->devPrivate.ptr;
-    pExaPixmap->sys_pitch = pPixmap->devKind;
-
-    pPixmap->devPrivate.ptr = NULL;
-    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);
-    pExaPixmap->fb_size = pExaPixmap->fb_pitch * h;
-
-    if (pExaPixmap->fb_pitch > 131071) {
-	fbDestroyPixmap(pPixmap);
-	return NULL;
-    }
-
     /* Set up damage tracking */
     pExaPixmap->pDamage = DamageCreate (NULL, NULL, DamageReportNone, TRUE,
 					pScreen, pPixmap);
@@ -315,6 +364,7 @@ exaModifyPixmapHeader(PixmapPtr pPixmap, int width, int height, int depth,
 {
     ExaScreenPrivPtr pExaScr;
     ExaPixmapPrivPtr pExaPixmap;
+    Bool ret;
 
     if (!pPixmap)
         return FALSE;
@@ -326,6 +376,12 @@ exaModifyPixmapHeader(PixmapPtr pPixmap, int width, int height, int depth,
 
     pExaScr = ExaGetScreenPriv(pPixmap->drawable.pScreen);
 
+    if (pExaScr->info->ModifyPixmapHeader) {
+	ret = pExaScr->info->ModifyPixmapHeader(pPixmap, width, height, depth,
+						bitsPerPixel, devKind, pPixData);
+	if (ret == TRUE)
+	    return ret;
+    }
     return pExaScr->SavedModifyPixmapHeader(pPixmap, width, height, depth,
 					    bitsPerPixel, devKind, pPixData);
 }
@@ -843,6 +899,7 @@ exaDriverInit (ScreenPtr		pScreen,
 
 	pExaScr->SavedModifyPixmapHeader = pScreen->ModifyPixmapHeader;
 	pScreen->ModifyPixmapHeader = exaModifyPixmapHeader;
+
 	LogMessage(X_INFO, "EXA(%d): Offscreen pixmap area of %d bytes\n",
 		   pScreen->myNum,
 		   pExaScr->info->memorySize - pExaScr->info->offScreenBase);

exa/exa.h

@@ -702,6 +702,13 @@ typedef struct _ExaDriver {
      */
     int maxPitchBytes;
 
+    /* Hooks to allow driver to its own pixmap memory management */
+    void *(*CreatePixmap)(ScreenPtr pScreen, int size, int align);
+    void (*DestroyPixmap)(ScreenPtr pScreen, void *driverPriv);
+    Bool (*ModifyPixmapHeader)(PixmapPtr pPixmap, int width, int height,
+                              int depth, int bitsPerPixel, int devKind,
+                              pointer pPixData);
+
     /** @} */
 } ExaDriverRec, *ExaDriverPtr;