[PATCH, RFC] adjust legacy IDE resource setting

["Jan Beulich" <jbeulich@novell.com>]

The change to force legacy mode IDE channels' resources to fixed
non-zero values confuses (at least some versions of) X, because the
values reported by the kernel and those readable from PCI config space
aren't consistent anymore. Therefore, this patch arranges for the
respective BARs to also get updated if possible.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

--- linux-2.6.20/drivers/pci/probe.c	2007-02-04 19:44:54.000000000 +0100
+++ 2.6.20-pci-ide-legacy/drivers/pci/probe.c	2007-02-14 15:54:58.000000000 +0100
@@ -639,7 +639,29 @@ static void pci_read_irq(struct pci_dev 
 	dev->irq = irq;
 }
 
-#define LEGACY_IO_RESOURCE	(IORESOURCE_IO | IORESOURCE_PCI_FIXED)
+static void change_legacy_io_resource(struct pci_dev * dev, unsigned index,
+                                      unsigned start, unsigned end)
+{
+	unsigned base = start & PCI_BASE_ADDRESS_IO_MASK;
+	unsigned len = (end | ~PCI_BASE_ADDRESS_IO_MASK) - base + 1;
+
+	if (!(pci_resource_flags(dev, index) & IORESOURCE_IO))
+		printk(KERN_WARNING "%s: cannot adjust BAR%u (not I/O)\n",
+		       pci_name(dev), index);
+	else if (pci_resource_len(dev, index) != len)
+		printk(KERN_WARNING "%s: cannot adjust BAR%u (size %04X)\n",
+		       pci_name(dev), index, (unsigned)pci_resource_len(dev, index));
+	else {
+		printk(KERN_INFO "%s: trying to change BAR%u from %04X to %04X\n",
+		       pci_name(dev), index,
+		       (unsigned)pci_resource_start(dev, index), base);
+		pci_write_config_dword(dev, PCI_BASE_ADDRESS_0 + index * 4, base);
+	}
+	pci_resource_start(dev, index) = start;
+	pci_resource_end(dev, index)   = end;
+	pci_resource_flags(dev, index) =
+		IORESOURCE_IO | IORESOURCE_PCI_FIXED | PCI_BASE_ADDRESS_SPACE_IO;
+}
 
 /**
  * pci_setup_device - fill in class and map information of a device
@@ -692,20 +714,12 @@ static int pci_setup_device(struct pci_d
 			u8 progif;
 			pci_read_config_byte(dev, PCI_CLASS_PROG, &progif);
 			if ((progif & 1) == 0) {
-				dev->resource[0].start = 0x1F0;
-				dev->resource[0].end = 0x1F7;
-				dev->resource[0].flags = LEGACY_IO_RESOURCE;
-				dev->resource[1].start = 0x3F6;
-				dev->resource[1].end = 0x3F6;
-				dev->resource[1].flags = LEGACY_IO_RESOURCE;
+				change_legacy_io_resource(dev, 0, 0x1F0, 0x1F7);
+				change_legacy_io_resource(dev, 1, 0x3F6, 0x3F6);
 			}
 			if ((progif & 4) == 0) {
-				dev->resource[2].start = 0x170;
-				dev->resource[2].end = 0x177;
-				dev->resource[2].flags = LEGACY_IO_RESOURCE;
-				dev->resource[3].start = 0x376;
-				dev->resource[3].end = 0x376;
-				dev->resource[3].flags = LEGACY_IO_RESOURCE;
+				change_legacy_io_resource(dev, 2, 0x170, 0x177);
+				change_legacy_io_resource(dev, 3, 0x376, 0x376);
 			}
 		}
 		break;