GIT: unionfs2-2.6.27.y: amd64-agp: Probe unknown AGP devices the right way

[Erez Zadok]

commit 51fcaa5075b5996a7e5f6ea11dec855f7dcb3976
Author: Ben Hutchings <ben at decadent.org.uk>
Date:   Wed Mar 24 03:36:31 2010 +0000

    amd64-agp: Probe unknown AGP devices the right way
    
    commit 6fd024893911dcb51b4a0aa71971db5ba38f7071 upstream.
    
    The current initialisation code probes 'unsupported' AGP devices
    simply by calling its own probe function.  It does not lock these
    devices or even check whether another driver is already bound to
    them.
    
    We must use the device core to manage this.  So if the specific
    device id table didn't match anything and agp_try_unsupported=1,
    switch the device id table and call driver_attach() again.
    
    Signed-off-by: Ben Hutchings <ben at decadent.org.uk>
    Signed-off-by: Dave Airlie <airlied at redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh at suse.de>

diff --git a/drivers/char/agp/amd64-agp.c b/drivers/char/agp/amd64-agp.c
index 7495c52..e144ad8 100644
--- a/drivers/char/agp/amd64-agp.c
+++ b/drivers/char/agp/amd64-agp.c
@@ -491,6 +491,10 @@ static int __devinit agp_amd64_probe(struct pci_dev *pdev,
 	u8 cap_ptr;
 	int err;
 
+	/* The Highlander principle */
+	if (agp_bridges_found)
+		return -ENODEV;
+
 	cap_ptr = pci_find_capability(pdev, PCI_CAP_ID_AGP);
 	if (!cap_ptr)
 		return -ENODEV;
@@ -554,6 +558,8 @@ static void __devexit agp_amd64_remove(struct pci_dev *pdev)
 			   amd64_aperture_sizes[bridge->aperture_size_idx].size);
 	agp_remove_bridge(bridge);
 	agp_put_bridge(bridge);
+
+	agp_bridges_found--;
 }
 
 #ifdef CONFIG_PM
@@ -701,6 +707,11 @@ static struct pci_device_id agp_amd64_pci_table[] = {
 
 MODULE_DEVICE_TABLE(pci, agp_amd64_pci_table);
 
+static DEFINE_PCI_DEVICE_TABLE(agp_amd64_pci_promisc_table) = {
+	{ PCI_DEVICE_CLASS(0, 0) },
+	{ }
+};
+
 static struct pci_driver agp_amd64_pci_driver = {
 	.name		= "agpgart-amd64",
 	.id_table	= agp_amd64_pci_table,
@@ -725,7 +736,6 @@ int __init agp_amd64_init(void)
 		return err;
 
 	if (agp_bridges_found == 0) {
-		struct pci_dev *dev;
 		if (!agp_try_unsupported && !agp_try_unsupported_boot) {
 			printk(KERN_INFO PFX "No supported AGP bridge found.\n");
 #ifdef MODULE
@@ -741,17 +751,10 @@ int __init agp_amd64_init(void)
 			return -ENODEV;
 
 		/* Look for any AGP bridge */
-		dev = NULL;
-		err = -ENODEV;
-		for_each_pci_dev(dev) {
-			if (!pci_find_capability(dev, PCI_CAP_ID_AGP))
-				continue;
-			/* Only one bridge supported right now */
-			if (agp_amd64_probe(dev, NULL) == 0) {
-				err = 0;
-				break;
-			}
-		}
+		agp_amd64_pci_driver.id_table = agp_amd64_pci_promisc_table;
+		err = driver_attach(&agp_amd64_pci_driver.driver);
+		if (err == 0 && agp_bridges_found == 0)
+			err = -ENODEV;
 	}
 	return err;
 }