4 files changed, 36 insertions, 9 deletions

diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index f1dd81a1d592..3cfb0a3575e6 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -19,7 +19,7 @@ config PCI_MSI
 
 config PCI_MULTITHREAD_PROBE
         bool "PCI Multi-threaded probe (EXPERIMENTAL)"
-        depends on PCI && EXPERIMENTAL
+        depends on PCI && EXPERIMENTAL && BROKEN
         help
           Say Y here if you want the PCI core to spawn a new thread for
           every PCI device that is probed.  This can cause a huge
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 6bfb942428e4..206c834d263a 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -254,7 +254,8 @@ static int __pci_find_next_ht_cap(struct pci_dev *dev, int pos, int ht_cap)
                 if ((cap & mask) == ht_cap)
                         return pos;
 
-                pos = __pci_find_next_cap_ttl(dev->bus, dev->devfn, pos,
+                pos = __pci_find_next_cap_ttl(dev->bus, dev->devfn,
+                                              pos + PCI_CAP_LIST_NEXT,
                                               PCI_CAP_ID_HT, &ttl);
         }
 
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 8f0322d6f3bf..0a70943f8bb6 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -955,7 +955,7 @@ DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8237, k8t_sound_ho
  * becomes necessary to do this tweak in two steps -- I've chosen the Host
  * bridge as trigger.
  */
-static int __initdata asus_hides_smbus;
+static int asus_hides_smbus;
 
 static void __init asus_hides_smbus_hostbridge(struct pci_dev *dev)
 {
@@ -1117,10 +1117,11 @@ DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_INTEL,	PCI_DEVICE_ID_INTEL_ICH6_1,	asus_h
 static void quirk_sis_96x_smbus(struct pci_dev *dev)
 {
         u8 val = 0;
-        printk(KERN_INFO "Enabling SiS 96x SMBus.\n");
-        pci_read_config_byte(dev, 0x77, &val);
-        pci_write_config_byte(dev, 0x77, val & ~0x10);
         pci_read_config_byte(dev, 0x77, &val);
+        if (val & 0x10) {
+                printk(KERN_INFO "Enabling SiS 96x SMBus.\n");
+                pci_write_config_byte(dev, 0x77, val & ~0x10);
+        }
 }
 
 /*
@@ -1152,11 +1153,12 @@ static void quirk_sis_503(struct pci_dev *dev)
         printk(KERN_WARNING "Uncovering SIS%x that hid as a SIS503 (compatible=%d)\n", devid, sis_96x_compatible);
 
         /*
-         * Ok, it now shows up as a 96x.. The 96x quirks are after
-         * the 503 quirk in the quirk table, so they'll automatically
-         * run and enable things like the SMBus device
+         * Ok, it now shows up as a 96x.. run the 96x quirk by
+         * hand in case it has already been processed.
+         * (depends on link order, which is apparently not guaranteed)
          */
         dev->device = devid;
+        quirk_sis_96x_smbus(dev);
 }
 
 static void __init quirk_sis_96x_compatible(struct pci_dev *dev)
diff --git a/drivers/pci/search.c b/drivers/pci/search.c
index 45f2b20ef513..fab381ed853c 100644
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -193,6 +193,18 @@ static struct pci_dev * pci_find_subsys(unsigned int vendor,
         struct pci_dev *dev;
 
         WARN_ON(in_interrupt());
+
+        /*
+         * pci_find_subsys() can be called on the ide_setup() path, super-early
+         * in boot.  But the down_read() will enable local interrupts, which
+         * can cause some machines to crash.  So here we detect and flag that
+         * situation and bail out early.
+         */
+        if (unlikely(list_empty(&pci_devices))) {
+                printk(KERN_INFO "pci_find_subsys() called while pci_devices "
+                                "is still empty\n");
+                return NULL;
+        }
         down_read(&pci_bus_sem);
         n = from ? from->global_list.next : pci_devices.next;
 
@@ -259,6 +271,18 @@ pci_get_subsys(unsigned int vendor, unsigned int device,
         struct pci_dev *dev;
 
         WARN_ON(in_interrupt());
+
+        /*
+         * pci_get_subsys() can potentially be called by drivers super-early
+         * in boot.  But the down_read() will enable local interrupts, which
+         * can cause some machines to crash.  So here we detect and flag that
+         * situation and bail out early.
+         */
+        if (unlikely(list_empty(&pci_devices))) {
+                printk(KERN_NOTICE "pci_get_subsys() called while pci_devices "
+                                "is still empty\n");
+                return NULL;
+        }
         down_read(&pci_bus_sem);
         n = from ? from->global_list.next : pci_devices.next;