Revert "ACPI: Ingore the RESET_REG_SUP bit when using ACPI reset mechanism"

This reverts commit 8fd145917fb62368a9b80db59562c20576238f5a.

http://bugzilla.kernel.org/show_bug.cgi?id=11942

Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 3 insertions, 22 deletions

diff --git a/drivers/acpi/reboot.c b/drivers/acpi/reboot.c
index 755baf2ca70a..a6b662c00b67 100644
--- a/drivers/acpi/reboot.c
+++ b/drivers/acpi/reboot.c
@@ -15,28 +15,9 @@ void acpi_reboot(void)
 
         rr = &acpi_gbl_FADT.reset_register;
 
-        /*
-         * Is the ACPI reset register supported?
-         *
-         * According to ACPI 3.0, FADT.flags.RESET_REG_SUP indicates
-         * whether the ACPI reset mechanism is supported.
-         *
-         * However, some boxes have this bit clear, yet a valid
-         * ACPI_RESET_REG & RESET_VALUE, and ACPI reboot is the only
-         * mechanism that works for them after S3.
-         *
-         * This suggests that other operating systems may not be checking
-         * the RESET_REG_SUP bit, and are using other means to decide
-         * whether to use the ACPI reboot mechanism or not.
-         *
-         * So when acpi reboot is requested,
-         * only the reset_register is checked. If the following
-         * conditions are met, it indicates that the reset register is supported.
-         *      a. reset_register is not zero
-         *      b. the access width is eight
-         *      c. the bit_offset is zero
-         */
-        if (!(rr->address) || rr->bit_width != 8 || rr->bit_offset != 0)
+        /* Is the reset register supported? */
+        if (!(acpi_gbl_FADT.flags & ACPI_FADT_RESET_REGISTER) ||
+            rr->bit_width != 8 || rr->bit_offset != 0)
                 return;
 
         reset_value = acpi_gbl_FADT.reset_value;