x86: if acpi=off, force setting the mmconf for fam10h

some BIOS only let AMD fam 10h handle bus0, and nvidia mcp55/ck804
to handle other buses. at that case MCFG will cover all over them.

but with acpi=off, we can not use MCFG. this patch will double check
the busnbits, and if it is less handling 256 bues, and acpi=off
will forcely reset the mmconf in msr, so we still use mmconf in above case.

Signed-off-by: Yinghai Lu <yinghai.lu@sun.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/setup_64.c b/arch/x86/kernel/setup_64.c
index 185d3cc9129b376d0a95242ae820066114dbff24..5e269a5dde2efc870ad1e0b568fdbcf237738c0a 100644 (file)
--- a/arch/x86/kernel/setup_64.c
+++ b/arch/x86/kernel/setup_64.c
@@ -751,14 +751,21 @@ static void __cpuinit fam10h_check_enable_mmcfg(struct cpuinfo_x86 *c)
 
        /* try to make sure that AP's setting is identical to BSP setting */
        if (val & FAM10H_MMIO_CONF_ENABLE) {
-               u64 base;
-               base = val & (0xffffULL << 32);
-               if (fam10h_pci_mmconf_base_status <= 0) {
-                       fam10h_pci_mmconf_base = base;
-                       fam10h_pci_mmconf_base_status = 1;
-                       return;
-               } else if (fam10h_pci_mmconf_base ==  base)
-                       return;
+               unsigned busnbits;
+               busnbits = (val >> FAM10H_MMIO_CONF_BUSRANGE_SHIFT) &
+                       FAM10H_MMIO_CONF_BUSRANGE_MASK;
+
+               /* only trust the one handle 256 buses, if acpi=off */
+               if (!acpi_pci_disabled || busnbits >= 8) {
+                       u64 base;
+                       base = val & (0xffffULL << 32);
+                       if (fam10h_pci_mmconf_base_status <= 0) {
+                               fam10h_pci_mmconf_base = base;
+                               fam10h_pci_mmconf_base_status = 1;
+                               return;
+                       } else if (fam10h_pci_mmconf_base ==  base)
+                               return;
+               }
        }
 
        /*