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-rw-r--r--Documentation/kernel-parameters.txt1
-rw-r--r--arch/ia64/kernel/acpi.c1
-rw-r--r--arch/x86/kernel/acpi/boot.c6
-rw-r--r--drivers/acpi/tables/tbutils.c3
-rw-r--r--include/acpi/acpixf.h1
5 files changed, 10 insertions, 2 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c9115c1b672..136f02842de 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -139,6 +139,7 @@ and is between 256 and 4096 characters. It is defined in the file
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 bd7acc71e8a..c19b686db9b 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -65,6 +65,7 @@ EXPORT_SYMBOL(pm_idle);
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 4c51a2f8fd3..db1a90a76b3 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 @@ static int __init parse_acpi(char *arg)
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 0cc92ef5236..da9f240186e 100644
--- a/drivers/acpi/tables/tbutils.c
+++ b/drivers/acpi/tables/tbutils.c
@@ -420,7 +420,8 @@ acpi_tb_parse_root_table(acpi_physical_address rsdp_address, u8 flags)
/* 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 33bc0e3b195..05d2614e007 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
*/