12 files changed, 182 insertions, 158 deletions

diff --git a/drivers/acpi/acpica/acconfig.h b/drivers/acpi/acpica/acconfig.h
index 33181ad350d5..b17d8de9f6ff 100644
--- a/drivers/acpi/acpica/acconfig.h
+++ b/drivers/acpi/acpica/acconfig.h
@@ -119,6 +119,10 @@
 
 #define ACPI_MAX_LOOP_ITERATIONS        0xFFFF
 
+/* Maximum sleep allowed via Sleep() operator */
+
+#define ACPI_MAX_SLEEP                  20000   /* Two seconds */
+
 /******************************************************************************
  *
  * ACPI Specification constants (Do not change unless the specification changes)
diff --git a/drivers/acpi/acpica/acevents.h b/drivers/acpi/acpica/acevents.h
index 64d1e5c2d4ae..c3f43daa8be3 100644
--- a/drivers/acpi/acpica/acevents.h
+++ b/drivers/acpi/acpica/acevents.h
@@ -80,10 +80,6 @@ u32 acpi_ev_gpe_detect(struct acpi_gpe_xrupt_info *gpe_xrupt_list);
 acpi_status
 acpi_ev_update_gpe_enable_masks(struct acpi_gpe_event_info *gpe_event_info);
 
-acpi_status acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info);
-
-acpi_status acpi_ev_disable_gpe(struct acpi_gpe_event_info *gpe_event_info);
-
 struct acpi_gpe_event_info *acpi_ev_get_gpe_event_info(acpi_handle gpe_device,
                                                        u32 gpe_number);
 
diff --git a/drivers/acpi/acpica/acglobal.h b/drivers/acpi/acpica/acglobal.h
index 9070f1fe8f17..899d68afc3c5 100644
--- a/drivers/acpi/acpica/acglobal.h
+++ b/drivers/acpi/acpica/acglobal.h
@@ -125,6 +125,14 @@ u8 ACPI_INIT_GLOBAL(acpi_gbl_enable_aml_debug_object, FALSE);
  */
 u8 ACPI_INIT_GLOBAL(acpi_gbl_copy_dsdt_locally, FALSE);
 
+/*
+ * Optionally truncate I/O addresses to 16 bits. Provides compatibility
+ * with other ACPI implementations. NOTE: During ACPICA initialization,
+ * this value is set to TRUE if any Windows OSI strings have been
+ * requested by the BIOS.
+ */
+u8 ACPI_INIT_GLOBAL(acpi_gbl_truncate_io_addresses, FALSE);
+
 /* acpi_gbl_FADT is a local copy of the FADT, converted to a common format. */
 
 struct acpi_table_fadt acpi_gbl_FADT;
diff --git a/drivers/acpi/acpica/achware.h b/drivers/acpi/acpica/achware.h
index 5900f135dc6d..32391588e163 100644
--- a/drivers/acpi/acpica/achware.h
+++ b/drivers/acpi/acpica/achware.h
@@ -90,7 +90,11 @@ acpi_status acpi_hw_write_port(acpi_io_address address, u32 value, u32 width);
 /*
  * hwgpe - GPE support
  */
-acpi_status acpi_hw_low_disable_gpe(struct acpi_gpe_event_info *gpe_event_info);
+u32 acpi_hw_gpe_register_bit(struct acpi_gpe_event_info *gpe_event_info,
+                             struct acpi_gpe_register_info *gpe_register_info);
+
+acpi_status
+acpi_hw_low_set_gpe(struct acpi_gpe_event_info *gpe_event_info, u8 action);
 
 acpi_status
 acpi_hw_write_gpe_enable_reg(struct acpi_gpe_event_info *gpe_event_info);
diff --git a/drivers/acpi/acpica/evgpe.c b/drivers/acpi/acpica/evgpe.c
index a221ad404167..7c2c336006a1 100644
--- a/drivers/acpi/acpica/evgpe.c
+++ b/drivers/acpi/acpica/evgpe.c
@@ -69,7 +69,7 @@ acpi_status
 acpi_ev_update_gpe_enable_masks(struct acpi_gpe_event_info *gpe_event_info)
 {
         struct acpi_gpe_register_info *gpe_register_info;
-        u8 register_bit;
+        u32 register_bit;
 
         ACPI_FUNCTION_TRACE(ev_update_gpe_enable_masks);
 
@@ -78,9 +78,8 @@ acpi_ev_update_gpe_enable_masks(struct acpi_gpe_event_info *gpe_event_info)
                 return_ACPI_STATUS(AE_NOT_EXIST);
         }
 
-        register_bit = (u8)
-            (1 <<
-             (gpe_event_info->gpe_number - gpe_register_info->base_gpe_number));
+        register_bit = acpi_hw_gpe_register_bit(gpe_event_info,
+                                                gpe_register_info);
 
         /* Clear the wake/run bits up front */
 
@@ -100,106 +99,6 @@ acpi_ev_update_gpe_enable_masks(struct acpi_gpe_event_info *gpe_event_info)
         return_ACPI_STATUS(AE_OK);
 }
 
-/*******************************************************************************
- *
- * FUNCTION:    acpi_ev_enable_gpe
- *
- * PARAMETERS:  gpe_event_info          - GPE to enable
- *
- * RETURN:      Status
- *
- * DESCRIPTION: Hardware-enable a GPE. Always enables the GPE, regardless
- *              of type or number of references.
- *
- * Note: The GPE lock should be already acquired when this function is called.
- *
- ******************************************************************************/
-
-acpi_status acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info)
-{
-        acpi_status status;
-
-
-        ACPI_FUNCTION_TRACE(ev_enable_gpe);
-
-
-        /*
-         * We will only allow a GPE to be enabled if it has either an
-         * associated method (_Lxx/_Exx) or a handler. Otherwise, the
-         * GPE will be immediately disabled by acpi_ev_gpe_dispatch the
-         * first time it fires.
-         */
-        if (!(gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK)) {
-                return_ACPI_STATUS(AE_NO_HANDLER);
-        }
-
-        /* Ensure the HW enable masks are current */
-
-        status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
-        if (ACPI_FAILURE(status)) {
-                return_ACPI_STATUS(status);
-        }
-
-        /* Clear the GPE (of stale events) */
-
-        status = acpi_hw_clear_gpe(gpe_event_info);
-        if (ACPI_FAILURE(status)) {
-                return_ACPI_STATUS(status);
-        }
-
-        /* Enable the requested GPE */
-
-        status = acpi_hw_write_gpe_enable_reg(gpe_event_info);
-        return_ACPI_STATUS(status);
-}
-
-/*******************************************************************************
- *
- * FUNCTION:    acpi_ev_disable_gpe
- *
- * PARAMETERS:  gpe_event_info          - GPE to disable
- *
- * RETURN:      Status
- *
- * DESCRIPTION: Hardware-disable a GPE. Always disables the requested GPE,
- *              regardless of the type or number of references.
- *
- * Note: The GPE lock should be already acquired when this function is called.
- *
- ******************************************************************************/
-
-acpi_status acpi_ev_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
-{
-        acpi_status status;
-
-        ACPI_FUNCTION_TRACE(ev_disable_gpe);
-
-
-        /*
-         * Note: Always disable the GPE, even if we think that that it is already
-         * disabled. It is possible that the AML or some other code has enabled
-         * the GPE behind our back.
-         */
-
-        /* Ensure the HW enable masks are current */
-
-        status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
-        if (ACPI_FAILURE(status)) {
-                return_ACPI_STATUS(status);
-        }
-
-        /*
-         * Always H/W disable this GPE, even if we don't know the GPE type.
-         * Simply clear the enable bit for this particular GPE, but do not
-         * write out the current GPE enable mask since this may inadvertently
-         * enable GPEs too early. An example is a rogue GPE that has arrived
-         * during ACPICA initialization - possibly because AML or other code
-         * has enabled the GPE.
-         */
-        status = acpi_hw_low_disable_gpe(gpe_event_info);
-        return_ACPI_STATUS(status);
-}
-
 
 /*******************************************************************************
  *
@@ -451,10 +350,6 @@ static void ACPI_SYSTEM_XFACE acpi_ev_asynch_execute_gpe_method(void *context)
                 return_VOID;
         }
 
-        /* Update the GPE register masks for return to enabled state */
-
-        (void)acpi_ev_update_gpe_enable_masks(gpe_event_info);
-
         /*
          * Take a snapshot of the GPE info for this level - we copy the info to
          * prevent a race condition with remove_handler/remove_block.
@@ -607,7 +502,7 @@ acpi_ev_gpe_dispatch(struct acpi_gpe_event_info *gpe_event_info, u32 gpe_number)
                  * Disable the GPE, so it doesn't keep firing before the method has a
                  * chance to run (it runs asynchronously with interrupts enabled).
                  */
-                status = acpi_ev_disable_gpe(gpe_event_info);
+                status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
                 if (ACPI_FAILURE(status)) {
                         ACPI_EXCEPTION((AE_INFO, status,
                                         "Unable to disable GPE[0x%2X]",
@@ -644,7 +539,7 @@ acpi_ev_gpe_dispatch(struct acpi_gpe_event_info *gpe_event_info, u32 gpe_number)
                  * Disable the GPE. The GPE will remain disabled a handler
                  * is installed or ACPICA is restarted.
                  */
-                status = acpi_ev_disable_gpe(gpe_event_info);
+                status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
                 if (ACPI_FAILURE(status)) {
                         ACPI_EXCEPTION((AE_INFO, status,
                                         "Unable to disable GPE[0x%2X]",
diff --git a/drivers/acpi/acpica/evgpeblk.c b/drivers/acpi/acpica/evgpeblk.c
index 7c28f2d9fd35..341a38ce8aa6 100644
--- a/drivers/acpi/acpica/evgpeblk.c
+++ b/drivers/acpi/acpica/evgpeblk.c
@@ -500,6 +500,19 @@ acpi_ev_initialize_gpe_block(struct acpi_namespace_node *gpe_device,
 
                         gpe_index = (i * ACPI_GPE_REGISTER_WIDTH) + j;
                         gpe_event_info = &gpe_block->event_info[gpe_index];
+                        gpe_number = gpe_index + gpe_block->block_base_number;
+
+                        /*
+                         * If the GPE has already been enabled for runtime
+                         * signaling, make sure it remains enabled, but do not
+                         * increment its reference counter.
+                         */
+                        if (gpe_event_info->runtime_count) {
+                                acpi_set_gpe(gpe_device, gpe_number,
+                                                ACPI_GPE_ENABLE);
+                                gpe_enabled_count++;
+                                continue;
+                        }
 
                         if (gpe_event_info->flags & ACPI_GPE_CAN_WAKE) {
                                 wake_gpe_count++;
@@ -516,7 +529,6 @@ acpi_ev_initialize_gpe_block(struct acpi_namespace_node *gpe_device,
 
                         /* Enable this GPE */
 
-                        gpe_number = gpe_index + gpe_block->block_base_number;
                         status = acpi_enable_gpe(gpe_device, gpe_number,
                                                  ACPI_GPE_TYPE_RUNTIME);
                         if (ACPI_FAILURE(status)) {
diff --git a/drivers/acpi/acpica/evxface.c b/drivers/acpi/acpica/evxface.c
index cc825023012a..4a531cdf7942 100644
--- a/drivers/acpi/acpica/evxface.c
+++ b/drivers/acpi/acpica/evxface.c
@@ -719,13 +719,6 @@ acpi_install_gpe_handler(acpi_handle gpe_device,
         handler->context = context;
         handler->method_node = gpe_event_info->dispatch.method_node;
 
-        /* Disable the GPE before installing the handler */
-
-        status = acpi_ev_disable_gpe(gpe_event_info);
-        if (ACPI_FAILURE (status)) {
-                goto unlock_and_exit;
-        }
-
         /* Install the handler */
 
         flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
diff --git a/drivers/acpi/acpica/evxfevnt.c b/drivers/acpi/acpica/evxfevnt.c
index d5a5efc043bf..d97b8dce1668 100644
--- a/drivers/acpi/acpica/evxfevnt.c
+++ b/drivers/acpi/acpica/evxfevnt.c
@@ -210,6 +210,44 @@ ACPI_EXPORT_SYMBOL(acpi_enable_event)
 
 /*******************************************************************************
  *
+ * FUNCTION:    acpi_clear_and_enable_gpe
+ *
+ * PARAMETERS:  gpe_event_info  - GPE to enable
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Clear the given GPE from stale events and enable it.
+ *
+ ******************************************************************************/
+static acpi_status
+acpi_clear_and_enable_gpe(struct acpi_gpe_event_info *gpe_event_info)
+{
+        acpi_status status;
+
+        /*
+         * We will only allow a GPE to be enabled if it has either an
+         * associated method (_Lxx/_Exx) or a handler. Otherwise, the
+         * GPE will be immediately disabled by acpi_ev_gpe_dispatch the
+         * first time it fires.
+         */
+        if (!(gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK)) {
+                return_ACPI_STATUS(AE_NO_HANDLER);
+        }
+
+        /* Clear the GPE (of stale events) */
+        status = acpi_hw_clear_gpe(gpe_event_info);
+        if (ACPI_FAILURE(status)) {
+                return_ACPI_STATUS(status);
+        }
+
+        /* Enable the requested GPE */
+        status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_ENABLE);
+
+        return_ACPI_STATUS(status);
+}
+
+/*******************************************************************************
+ *
  * FUNCTION:    acpi_set_gpe
  *
  * PARAMETERS:  gpe_device      - Parent GPE Device. NULL for GPE0/GPE1
@@ -249,11 +287,11 @@ acpi_status acpi_set_gpe(acpi_handle gpe_device, u32 gpe_number, u8 action)
 
         switch (action) {
         case ACPI_GPE_ENABLE:
-                status = acpi_ev_enable_gpe(gpe_event_info);
+                status = acpi_clear_and_enable_gpe(gpe_event_info);
                 break;
 
         case ACPI_GPE_DISABLE:
-                status = acpi_ev_disable_gpe(gpe_event_info);
+                status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
                 break;
 
         default:
@@ -316,7 +354,11 @@ acpi_status acpi_enable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 gpe_type)
 
                 gpe_event_info->runtime_count++;
                 if (gpe_event_info->runtime_count == 1) {
-                        status = acpi_ev_enable_gpe(gpe_event_info);
+                        status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
+                        if (ACPI_SUCCESS(status)) {
+                                status = acpi_clear_and_enable_gpe(gpe_event_info);
+                        }
+
                         if (ACPI_FAILURE(status)) {
                                 gpe_event_info->runtime_count--;
                                 goto unlock_and_exit;
@@ -343,7 +385,7 @@ acpi_status acpi_enable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 gpe_type)
                  */
                 gpe_event_info->wakeup_count++;
                 if (gpe_event_info->wakeup_count == 1) {
-                        (void)acpi_ev_update_gpe_enable_masks(gpe_event_info);
+                        status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
                 }
         }
 
@@ -403,7 +445,12 @@ acpi_status acpi_disable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 gpe_type
 
                 gpe_event_info->runtime_count--;
                 if (!gpe_event_info->runtime_count) {
-                        status = acpi_ev_disable_gpe(gpe_event_info);
+                        status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
+                        if (ACPI_SUCCESS(status)) {
+                                status = acpi_hw_low_set_gpe(gpe_event_info,
+                                                             ACPI_GPE_DISABLE);
+                        }
+
                         if (ACPI_FAILURE(status)) {
                                 gpe_event_info->runtime_count++;
                                 goto unlock_and_exit;
@@ -424,7 +471,7 @@ acpi_status acpi_disable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 gpe_type
 
                 gpe_event_info->wakeup_count--;
                 if (!gpe_event_info->wakeup_count) {
-                        (void)acpi_ev_update_gpe_enable_masks(gpe_event_info);
+                        status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
                 }
         }
 
diff --git a/drivers/acpi/acpica/exsystem.c b/drivers/acpi/acpica/exsystem.c
index 6d32e09327f1..675aaa91a770 100644
--- a/drivers/acpi/acpica/exsystem.c
+++ b/drivers/acpi/acpica/exsystem.c
@@ -201,6 +201,14 @@ acpi_status acpi_ex_system_do_sleep(u64 how_long)
 
         acpi_ex_relinquish_interpreter();
 
+        /*
+         * For compatibility with other ACPI implementations and to prevent
+         * accidental deep sleeps, limit the sleep time to something reasonable.
+         */
+        if (how_long > ACPI_MAX_SLEEP) {
+                how_long = ACPI_MAX_SLEEP;
+        }
+
         acpi_os_sleep(how_long);
 
         /* And now we must get the interpreter again */
diff --git a/drivers/acpi/acpica/hwgpe.c b/drivers/acpi/acpica/hwgpe.c
index bd72319a38f0..3450309c2786 100644
--- a/drivers/acpi/acpica/hwgpe.c
+++ b/drivers/acpi/acpica/hwgpe.c
@@ -57,21 +57,47 @@ acpi_hw_enable_wakeup_gpe_block(struct acpi_gpe_xrupt_info *gpe_xrupt_info,
 
 /******************************************************************************
  *
- * FUNCTION:    acpi_hw_low_disable_gpe
+ * FUNCTION:    acpi_hw_gpe_register_bit
+ *
+ * PARAMETERS:  gpe_event_info      - Info block for the GPE
+ *              gpe_register_info   - Info block for the GPE register
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Compute GPE enable mask with one bit corresponding to the given
+ *              GPE set.
+ *
+ ******************************************************************************/
+
+u32 acpi_hw_gpe_register_bit(struct acpi_gpe_event_info *gpe_event_info,
+                             struct acpi_gpe_register_info *gpe_register_info)
+{
+        return (u32)1 << (gpe_event_info->gpe_number -
+                                gpe_register_info->base_gpe_number);
+}
+
+/******************************************************************************
+ *
+ * FUNCTION:    acpi_hw_low_set_gpe
  *
  * PARAMETERS:  gpe_event_info      - Info block for the GPE to be disabled
+ *              action              - Enable or disable
  *
  * RETURN:      Status
  *
- * DESCRIPTION: Disable a single GPE in the enable register.
+ * DESCRIPTION: Enable or disable a single GPE in its enable register.
  *
  ******************************************************************************/
 
-acpi_status acpi_hw_low_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
+acpi_status
+acpi_hw_low_set_gpe(struct acpi_gpe_event_info *gpe_event_info, u8 action)
 {
         struct acpi_gpe_register_info *gpe_register_info;
         acpi_status status;
         u32 enable_mask;
+        u32 register_bit;
+
+        ACPI_FUNCTION_ENTRY();
 
         /* Get the info block for the entire GPE register */
 
@@ -87,11 +113,27 @@ acpi_status acpi_hw_low_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
                 return (status);
         }
 
-        /* Clear just the bit that corresponds to this GPE */
+        /* Set ot clear just the bit that corresponds to this GPE */
 
-        ACPI_CLEAR_BIT(enable_mask, ((u32)1 <<
-                                     (gpe_event_info->gpe_number -
-                                      gpe_register_info->base_gpe_number)));
+        register_bit = acpi_hw_gpe_register_bit(gpe_event_info,
+                                                gpe_register_info);
+        switch (action) {
+        case ACPI_GPE_COND_ENABLE:
+                if (!(register_bit & gpe_register_info->enable_for_run))
+                        return (AE_BAD_PARAMETER);
+
+        case ACPI_GPE_ENABLE:
+                ACPI_SET_BIT(enable_mask, register_bit);
+                break;
+
+        case ACPI_GPE_DISABLE:
+                ACPI_CLEAR_BIT(enable_mask, register_bit);
+                break;
+
+        default:
+                ACPI_ERROR((AE_INFO, "Invalid action\n"));
+                return (AE_BAD_PARAMETER);
+        }
 
         /* Write the updated enable mask */
 
@@ -116,23 +158,11 @@ acpi_status acpi_hw_low_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
 acpi_status
 acpi_hw_write_gpe_enable_reg(struct acpi_gpe_event_info * gpe_event_info)
 {
-        struct acpi_gpe_register_info *gpe_register_info;
         acpi_status status;
 
         ACPI_FUNCTION_ENTRY();
 
-        /* Get the info block for the entire GPE register */
-
-        gpe_register_info = gpe_event_info->register_info;
-        if (!gpe_register_info) {
-                return (AE_NOT_EXIST);
-        }
-
-        /* Write the entire GPE (runtime) enable register */
-
-        status = acpi_hw_write(gpe_register_info->enable_for_run,
-                               &gpe_register_info->enable_address);
-
+        status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_COND_ENABLE);
         return (status);
 }
 
@@ -150,21 +180,28 @@ acpi_hw_write_gpe_enable_reg(struct acpi_gpe_event_info * gpe_event_info)
 
 acpi_status acpi_hw_clear_gpe(struct acpi_gpe_event_info * gpe_event_info)
 {
+        struct acpi_gpe_register_info *gpe_register_info;
         acpi_status status;
-        u8 register_bit;
+        u32 register_bit;
 
         ACPI_FUNCTION_ENTRY();
 
-        register_bit = (u8)(1 <<
-                            (gpe_event_info->gpe_number -
-                             gpe_event_info->register_info->base_gpe_number));
+        /* Get the info block for the entire GPE register */
+
+        gpe_register_info = gpe_event_info->register_info;
+        if (!gpe_register_info) {
+                return (AE_NOT_EXIST);
+        }
+
+        register_bit = acpi_hw_gpe_register_bit(gpe_event_info,
+                                                gpe_register_info);
 
         /*
          * Write a one to the appropriate bit in the status register to
          * clear this GPE.
          */
         status = acpi_hw_write(register_bit,
-                               &gpe_event_info->register_info->status_address);
+                               &gpe_register_info->status_address);
 
         return (status);
 }
@@ -187,7 +224,7 @@ acpi_hw_get_gpe_status(struct acpi_gpe_event_info * gpe_event_info,
                        acpi_event_status * event_status)
 {
         u32 in_byte;
-        u8 register_bit;
+        u32 register_bit;
         struct acpi_gpe_register_info *gpe_register_info;
         acpi_status status;
         acpi_event_status local_event_status = 0;
@@ -204,9 +241,8 @@ acpi_hw_get_gpe_status(struct acpi_gpe_event_info * gpe_event_info,
 
         /* Get the register bitmask for this GPE */
 
-        register_bit = (u8)(1 <<
-                            (gpe_event_info->gpe_number -
-                             gpe_event_info->register_info->base_gpe_number));
+        register_bit = acpi_hw_gpe_register_bit(gpe_event_info,
+                                                gpe_register_info);
 
         /* GPE currently enabled? (enabled for runtime?) */
 
diff --git a/drivers/acpi/acpica/hwvalid.c b/drivers/acpi/acpica/hwvalid.c
index c10d587c1641..e1d9c777b213 100644
--- a/drivers/acpi/acpica/hwvalid.c
+++ b/drivers/acpi/acpica/hwvalid.c
@@ -222,6 +222,12 @@ acpi_status acpi_hw_read_port(acpi_io_address address, u32 *value, u32 width)
         u32 one_byte;
         u32 i;
 
+        /* Truncate address to 16 bits if requested */
+
+        if (acpi_gbl_truncate_io_addresses) {
+                address &= ACPI_UINT16_MAX;
+        }
+
         /* Validate the entire request and perform the I/O */
 
         status = acpi_hw_validate_io_request(address, width);
@@ -279,6 +285,12 @@ acpi_status acpi_hw_write_port(acpi_io_address address, u32 value, u32 width)
         acpi_status status;
         u32 i;
 
+        /* Truncate address to 16 bits if requested */
+
+        if (acpi_gbl_truncate_io_addresses) {
+                address &= ACPI_UINT16_MAX;
+        }
+
         /* Validate the entire request and perform the I/O */
 
         status = acpi_hw_validate_io_request(address, width);
diff --git a/drivers/acpi/acpica/nsinit.c b/drivers/acpi/acpica/nsinit.c
index 9bd6f050f299..4e5272c313e0 100644
--- a/drivers/acpi/acpica/nsinit.c
+++ b/drivers/acpi/acpica/nsinit.c
@@ -193,6 +193,15 @@ acpi_status acpi_ns_initialize_devices(void)
                                         acpi_ns_init_one_device, NULL, &info,
                                         NULL);
 
+        /*
+         * Any _OSI requests should be completed by now. If the BIOS has
+         * requested any Windows OSI strings, we will always truncate
+         * I/O addresses to 16 bits -- for Windows compatibility.
+         */
+        if (acpi_gbl_osi_data >= ACPI_OSI_WIN_2000) {
+                acpi_gbl_truncate_io_addresses = TRUE;
+        }
+
         ACPI_FREE(info.evaluate_info);
         if (ACPI_FAILURE(status)) {
                 goto error_exit;