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authorAndi Kleen <ak@suse.de>2006-09-26 10:52:41 +0200
committerAndi Kleen <andi@basil.nowhere.org>2006-09-26 10:52:41 +0200
commit0637a70a5db98182d9ad3d6ae1ee30acf20afde9 (patch)
tree36b625e24f3fe11a97cd9926ca2be6b2df1cbf89 /arch/i386
parent8f60774a116ced9b73ae3913d511687889efe725 (diff)
[PATCH] x86: Allow disabling early pci scans with pci=noearly or disallowing conf1
Some buggy systems can machine check when config space accesses happen for some non existent devices. i386/x86-64 do some early device scans that might trigger this. Allow pci=noearly to disable this. Also when type 1 is disabling also don't do any early accesses which are always type1. This moves the pci= configuration parsing to be a early parameter. I don't think this can break anything because it only changes a single global that is only used by PCI. Cc: gregkh@suse.de Cc: Trammell Hudson <hudson@osresearch.net> Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/i386')
-rw-r--r--arch/i386/kernel/acpi/earlyquirk.c6
-rw-r--r--arch/i386/pci/common.c4
-rw-r--r--arch/i386/pci/early.c8
-rw-r--r--arch/i386/pci/pci.h1
4 files changed, 18 insertions, 1 deletions
diff --git a/arch/i386/kernel/acpi/earlyquirk.c b/arch/i386/kernel/acpi/earlyquirk.c
index 1649a175a20..fe799b11ac0 100644
--- a/arch/i386/kernel/acpi/earlyquirk.c
+++ b/arch/i386/kernel/acpi/earlyquirk.c
@@ -48,7 +48,11 @@ void __init check_acpi_pci(void)
int num, slot, func;
/* Assume the machine supports type 1. If not it will
- always read ffffffff and should not have any side effect. */
+ always read ffffffff and should not have any side effect.
+ Actually a few buggy systems can machine check. Allow the user
+ to disable it by command line option at least -AK */
+ if (!early_pci_allowed())
+ return;
/* Poor man's PCI discovery */
for (num = 0; num < 32; num++) {
diff --git a/arch/i386/pci/common.c b/arch/i386/pci/common.c
index 0a362e3aeac..68bce194e68 100644
--- a/arch/i386/pci/common.c
+++ b/arch/i386/pci/common.c
@@ -242,6 +242,10 @@ char * __devinit pcibios_setup(char *str)
acpi_noirq_set();
return NULL;
}
+ else if (!strcmp(str, "noearly")) {
+ pci_probe |= PCI_PROBE_NOEARLY;
+ return NULL;
+ }
#ifndef CONFIG_X86_VISWS
else if (!strcmp(str, "usepirqmask")) {
pci_probe |= PCI_USE_PIRQ_MASK;
diff --git a/arch/i386/pci/early.c b/arch/i386/pci/early.c
index b1f7f40d809..713d6c866ca 100644
--- a/arch/i386/pci/early.c
+++ b/arch/i386/pci/early.c
@@ -1,6 +1,8 @@
#include <linux/kernel.h>
+#include <linux/pci.h>
#include <asm/pci-direct.h>
#include <asm/io.h>
+#include "pci.h"
/* Direct PCI access. This is used for PCI accesses in early boot before
the PCI subsystem works. */
@@ -42,3 +44,9 @@ void write_pci_config(u8 bus, u8 slot, u8 func, u8 offset,
outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
outl(val, 0xcfc);
}
+
+int early_pci_allowed(void)
+{
+ return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==
+ PCI_PROBE_CONF1;
+}
diff --git a/arch/i386/pci/pci.h b/arch/i386/pci/pci.h
index 8a7cf1f2368..1814f74569c 100644
--- a/arch/i386/pci/pci.h
+++ b/arch/i386/pci/pci.h
@@ -17,6 +17,7 @@
#define PCI_PROBE_CONF2 0x0004
#define PCI_PROBE_MMCONF 0x0008
#define PCI_PROBE_MASK 0x000f
+#define PCI_PROBE_NOEARLY 0x0010
#define PCI_NO_SORT 0x0100
#define PCI_BIOS_SORT 0x0200