ACPI : Use RSDT instead of XSDT by adding boot option of "acpi=rsdt"
On some boxes there exist both RSDT and XSDT table. But unfortunately
sometimes there exists the following error when XSDT table is used:
a. 32/64X address mismatch
b. The 32/64X FACS address mismatch
In such case the boot option of "acpi=rsdt" is provided so that
RSDT is tried instead of XSDT table when the system can't work well.
http://bugzilla.kernel.org/show_bug.cgi?id=8246
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
cc:Thomas Renninger <trenn@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c9115c1..136f028 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -139,6 +139,7 @@
ht -- run only enough ACPI to enable Hyper Threading
strict -- Be less tolerant of platforms that are not
strictly ACPI specification compliant.
+ rsdt -- prefer RSDT over (default) XSDT
See also Documentation/power/pm.txt, pci=noacpi
diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index bd7acc7..c19b686 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -65,6 +65,7 @@
void (*pm_power_off) (void);
EXPORT_SYMBOL(pm_power_off);
+u32 acpi_rsdt_forced;
unsigned int acpi_cpei_override;
unsigned int acpi_cpei_phys_cpuid;
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 4c51a2f..db1a90a 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -47,7 +47,7 @@
#endif
static int __initdata acpi_force = 0;
-
+u32 acpi_rsdt_forced;
#ifdef CONFIG_ACPI
int acpi_disabled = 0;
#else
@@ -1783,6 +1783,10 @@
disable_acpi();
acpi_ht = 1;
}
+ /* acpi=rsdt use RSDT instead of XSDT */
+ else if (strcmp(arg, "rsdt") == 0) {
+ acpi_rsdt_forced = 1;
+ }
/* "acpi=noirq" disables ACPI interrupt routing */
else if (strcmp(arg, "noirq") == 0) {
acpi_noirq_set();
diff --git a/drivers/acpi/tables/tbutils.c b/drivers/acpi/tables/tbutils.c
index 0cc92ef..da9f240 100644
--- a/drivers/acpi/tables/tbutils.c
+++ b/drivers/acpi/tables/tbutils.c
@@ -420,7 +420,8 @@
/* Differentiate between RSDT and XSDT root tables */
- if (rsdp->revision > 1 && rsdp->xsdt_physical_address) {
+ if (rsdp->revision > 1 && rsdp->xsdt_physical_address
+ && !acpi_rsdt_forced) {
/*
* Root table is an XSDT (64-bit physical addresses). We must use the
* XSDT if the revision is > 1 and the XSDT pointer is present, as per
diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
index 33bc0e3b1..05d2614 100644
--- a/include/acpi/acpixf.h
+++ b/include/acpi/acpixf.h
@@ -48,6 +48,7 @@
#include "actypes.h"
#include "actbl.h"
+extern u32 acpi_rsdt_forced;
/*
* Global interfaces
*/