Subject: offb issue
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>


My latest patch for fixing MAUI & some pSeries with matrox also broke
some powermacs with nvidia... This patch is an attempt at fixing it all
against current upstream but I need tests on MAUI/ATX/pSeries to make
sure it doesn't regress.


Signed-off-by: Olaf Hering <olh@suse.de>

Index: linux-work/drivers/video/offb.c
===================================================================
--- linux-work.orig/drivers/video/offb.c	2005-11-19 10:56:08.000000000 +1100
+++ linux-work/drivers/video/offb.c	2005-12-19 11:02:57.000000000 +1100
@@ -326,7 +326,7 @@
 	int *pp, i;
 	unsigned int len;
 	int width = 640, height = 480, depth = 8, pitch;
-	unsigned int rsize, *up;
+	unsigned int rsize, *up, addr_prop = 0;
 	unsigned long address = 0;
 
 	if ((pp = (int *) get_property(dp, "depth", &len)) != NULL
@@ -346,63 +346,69 @@
 	} else
 		pitch = width;
 
-       rsize = (unsigned long)pitch * (unsigned long)height *
+	rsize = (unsigned long)pitch * (unsigned long)height *
                (unsigned long)(depth / 8);
 
-       /* Try to match device to a PCI device in order to get a properly
-	* translated address rather then trying to decode the open firmware
-	* stuff in various incorrect ways
-	*/
+	/* Ok, now we try to figure out the address of the framebuffer.
+	 *
+	 * Unfortunately, Open Firmware doesn't provide a standard way to do
+	 * so. All we can do is a dodgy heuristic that happens to work in
+	 * practice. On most machines, the "address" property contains what
+	 * we need, though not on Matrox cards found in IBM machines. What I've
+	 * found that appears to give good results is to go through the PCI
+	 * ranges and pick one that is both big enough and if possible encloses
+	 * the "address" property. If none match, we pick the biggest
+	 */
+	up = (unsigned int *) get_property(dp, "address", &len);
+	if (up && len == sizeof(unsigned int))
+		addr_prop = *up;
+
 #ifdef CONFIG_PCI
-       /* First try to locate the PCI device if any */
-       {
-               struct pci_dev *pdev = NULL;
-
-	       for_each_pci_dev(pdev) {
-                       if (dp == pci_device_to_OF_node(pdev))
-                               break;
-	       }
-               if (pdev) {
-                       for (i = 0; i < 6 && address == 0; i++) {
-                               if ((pci_resource_flags(pdev, i) &
-				    IORESOURCE_MEM) &&
-				   (pci_resource_len(pdev, i) >= rsize))
-                                       address = pci_resource_start(pdev, i);
-                       }
-		       pci_dev_put(pdev);
-               }
-        }
-#endif /* CONFIG_PCI */
+	/* Try to locate the PCI device if any */
+	{
+		struct pci_dev *pdev = NULL;
 
-	if (address == 0 &&
-	    (up = (unsigned *) get_property(dp, "address", &len)) != NULL &&
-	    len == sizeof(unsigned))
-		address = (u_long) * up;
-	if (address == 0) {
-		for (i = 0; i < dp->n_addrs; ++i)
-			if (dp->addrs[i].size >=
-			    pitch * height * depth / 8)
+		for_each_pci_dev(pdev) {
+			if (dp == pci_device_to_OF_node(pdev))
 				break;
-		if (i >= dp->n_addrs) {
-			printk(KERN_ERR
-			       "no framebuffer address found for %s\n",
-			       dp->full_name);
-			return;
 		}
+		if (pdev) {
+			unsigned long max_size = 0;
 
-		address = (u_long) dp->addrs[i].address;
+			for (i = 0; i < 6 && address == 0; i++) {
+				int match_addrp = 0;
 
-#ifdef CONFIG_PPC64
-		address += ((struct pci_dn *)dp->data)->phb->pci_mem_offset;
-#endif
-
-		/* kludge for valkyrie */
-		if (strcmp(dp->name, "valkyrie") == 0)
-			address += 0x1000;
-	}
-	offb_init_fb(dp->name, dp->full_name, width, height, depth,
-		     pitch, address, dp);
+				if (!pci_resource_flags(pdev, i)&IORESOURCE_MEM)
+					continue;
+				if (pci_resource_len(pdev, i) < rsize)
+					continue;
+				if (addr_prop && pci_resource_start(pdev, i) <=
+				    addr_prop && (pci_resource_start(pdev, i) +
+						  pci_resource_len(pdev, i) >
+						  addr_prop))
+					match_addrp = 1;
+				if (match_addrp) {
+					address = addr_prop;
+					break;
+				}
+				if (pci_resource_len(pdev, i) > max_size) {
+					max_size = pci_resource_len(pdev, i);
+					address = 0;
+				}
+				if (address == 0)
+					address = pci_resource_start(pdev, i);
+			}
+			pci_dev_put(pdev);
+		}
+        }
+#endif /* CONFIG_PCI */
+
+	if (address == 0 && addr_prop)
+		address = (u_long)addr_prop;
 
+	if (address != 0)
+		offb_init_fb(dp->name, dp->full_name, width, height, depth,
+			     pitch, address, dp);
 }
 
 static void __init offb_init_fb(const char *name, const char *full_name,