[PATCH] PCI: use PCBIOS as last fallback

there was a change in 2.6.17 which affected the order in which the PCI
access methods are probed.  this gives regressions on some machines with
broken BIOS.  the problem is that PCBIOS sometimes reports last bus wrong,
leaving cardbus non-funcational.  previously those system worked fine with
direct access.

The patch changes the PCI init code to have PCBIOS as last fallback, yet
the PCBIOS code still has to run first to set pcibios_last_bus to the value
reported by the BIOS.  this is needed in case legacy PCI probing
(arch/i386/pci/legacy.c) is used to detect peer busses.  using direct
access if available fixes the cardbus problems.

Signed-off-by: Daniel Ritz <daniel.ritz@gmx.ch>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 6 insertions, 2 deletions

diff --git a/arch/i386/pci/init.c b/arch/i386/pci/init.c
index c7650a7e0b07..51087a9d9172 100644
--- a/arch/i386/pci/init.c
+++ b/arch/i386/pci/init.c
@@ -14,8 +14,12 @@ static __init int pci_access_init(void)
 #ifdef CONFIG_PCI_BIOS
         pci_pcbios_init();
 #endif
-        if (raw_pci_ops)
-                return 0;
+        /*
+         * don't check for raw_pci_ops here because we want pcbios as last
+         * fallback, yet it's needed to run first to set pcibios_last_bus
+         * in case legacy PCI probing is used. otherwise detecting peer busses
+         * fails.
+         */
 #ifdef CONFIG_PCI_DIRECT
         pci_direct_init();
 #endif