Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

Conflicts:
	include/linux/serial_sci.h

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

12 files changed, 182 insertions, 158 deletions

diff --git a/drivers/acpi/acpica/acconfig.h b/drivers/acpi/acpica/acconfig.h
index 33181ad350d..b17d8de9f6f 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 64d1e5c2d4a..c3f43daa8be 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 9070f1fe8f1..899d68afc3c 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 5900f135dc6..32391588e16 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 a221ad40416..7c2c336006a 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 7c28f2d9fd3..341a38ce8aa 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 cc825023012..4a531cdf794 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 d5a5efc043b..d97b8dce166 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 6d32e09327f..675aaa91a77 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 bd72319a38f..3450309c278 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 c10d587c164..e1d9c777b21 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 9bd6f050f29..4e5272c313e 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;