[ACPI] properly detect pmtimer on ASUS a8v motherboard
Handle FADT 2.0 xpmtmr address 0 case.
http://bugzilla.kernel.org/show_bug.cgi?id=5283
Signed-off-by: Shaohua Li<shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/arch/i386/kernel/acpi/boot.c b/arch/i386/kernel/acpi/boot.c
index 76b1135..447fa9e 100644
--- a/arch/i386/kernel/acpi/boot.c
+++ b/arch/i386/kernel/acpi/boot.c
@@ -638,6 +638,13 @@
return 0;
pmtmr_ioport = fadt->xpm_tmr_blk.address;
+ /*
+ * "X" fields are optional extensions to the original V1.0
+ * fields, so we must selectively expand V1.0 fields if the
+ * corresponding X field is zero.
+ */
+ if (!pmtmr_ioport)
+ pmtmr_ioport = fadt->V1_pm_tmr_blk;
} else {
/* FADT rev. 1 */
pmtmr_ioport = fadt->V1_pm_tmr_blk;