diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index f9961034e557..82e508677b91 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -162,8 +162,6 @@ static int __init acpi_sleep_setup(char *str)
 #endif
 		if (strncmp(str, "old_ordering", 12) == 0)
 			acpi_old_suspend_ordering();
-		if (strncmp(str, "sci_force_enable", 16) == 0)
-			acpi_set_sci_en_on_resume();
 		str = strchr(str, ',');
 		if (str != NULL)
 			str += strspn(str, ", \t");
diff --git a/drivers/acpi/acpica/evxfevnt.c b/drivers/acpi/acpica/evxfevnt.c
index 5ff32c78ea2d..bfbe291d572e 100644
--- a/drivers/acpi/acpica/evxfevnt.c
+++ b/drivers/acpi/acpica/evxfevnt.c
@@ -69,7 +69,7 @@ acpi_ev_get_gpe_device(struct acpi_gpe_xrupt_info *gpe_xrupt_info,
 
 acpi_status acpi_enable(void)
 {
-	acpi_status status = AE_OK;
+	acpi_status status;
 
 	ACPI_FUNCTION_TRACE(acpi_enable);
 
@@ -84,21 +84,30 @@ acpi_status acpi_enable(void)
 	if (acpi_hw_get_mode() == ACPI_SYS_MODE_ACPI) {
 		ACPI_DEBUG_PRINT((ACPI_DB_INIT,
 				  "System is already in ACPI mode\n"));
-	} else {
-		/* Transition to ACPI mode */
-
-		status = acpi_hw_set_mode(ACPI_SYS_MODE_ACPI);
-		if (ACPI_FAILURE(status)) {
-			ACPI_ERROR((AE_INFO,
-				    "Could not transition to ACPI mode"));
-			return_ACPI_STATUS(status);
-		}
-
-		ACPI_DEBUG_PRINT((ACPI_DB_INIT,
-				  "Transition to ACPI mode successful\n"));
+		return_ACPI_STATUS(AE_OK);
 	}
 
-	return_ACPI_STATUS(status);
+	/* Transition to ACPI mode */
+
+	status = acpi_hw_set_mode(ACPI_SYS_MODE_ACPI);
+	if (ACPI_FAILURE(status)) {
+		ACPI_ERROR((AE_INFO,
+			    "Could not transition to ACPI mode"));
+		return_ACPI_STATUS(status);
+	}
+
+	/* Sanity check that transition succeeded */
+
+	if (acpi_hw_get_mode() != ACPI_SYS_MODE_ACPI) {
+		ACPI_ERROR((AE_INFO,
+			    "Hardware did not enter ACPI mode"));
+		return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
+	}
+
+	ACPI_DEBUG_PRINT((ACPI_DB_INIT,
+			  "Transition to ACPI mode successful\n"));
+
+	return_ACPI_STATUS(AE_OK);
 }
 
 ACPI_EXPORT_SYMBOL(acpi_enable)
diff --git a/drivers/acpi/acpica/hwacpi.c b/drivers/acpi/acpica/hwacpi.c
index 679a112a7d26..b44274a0b62c 100644
--- a/drivers/acpi/acpica/hwacpi.c
+++ b/drivers/acpi/acpica/hwacpi.c
@@ -63,7 +63,6 @@ acpi_status acpi_hw_set_mode(u32 mode)
 {
 
 	acpi_status status;
-	u32 retry;
 
 	ACPI_FUNCTION_TRACE(hw_set_mode);
 
@@ -125,24 +124,7 @@ acpi_status acpi_hw_set_mode(u32 mode)
 		return_ACPI_STATUS(status);
 	}
 
-	/*
-	 * Some hardware takes a LONG time to switch modes. Give them 3 sec to
-	 * do so, but allow faster systems to proceed more quickly.
-	 */
-	retry = 3000;
-	while (retry) {
-		if (acpi_hw_get_mode() == mode) {
-			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-					  "Mode %X successfully enabled\n",
-					  mode));
-			return_ACPI_STATUS(AE_OK);
-		}
-		acpi_os_stall(1000);
-		retry--;
-	}
-
-	ACPI_ERROR((AE_INFO, "Hardware did not change modes"));
-	return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
+	return_ACPI_STATUS(AE_OK);
 }
 
 /*******************************************************************************
diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index baa76bbf244a..4ab2275b4461 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -80,22 +80,6 @@ static int acpi_sleep_prepare(u32 acpi_state)
 
 #ifdef CONFIG_ACPI_SLEEP
 static u32 acpi_target_sleep_state = ACPI_STATE_S0;
-/*
- * According to the ACPI specification the BIOS should make sure that ACPI is
- * enabled and SCI_EN bit is set on wake-up from S1 - S3 sleep states.  Still,
- * some BIOSes don't do that and therefore we use acpi_enable() to enable ACPI
- * on such systems during resume.  Unfortunately that doesn't help in
- * particularly pathological cases in which SCI_EN has to be set directly on
- * resume, although the specification states very clearly that this flag is
- * owned by the hardware.  The set_sci_en_on_resume variable will be set in such
- * cases.
- */
-static bool set_sci_en_on_resume;
-
-void __init acpi_set_sci_en_on_resume(void)
-{
-	set_sci_en_on_resume = true;
-}
 
 /*
  * ACPI 1.0 wants us to execute _PTS before suspending devices, so we allow the
@@ -253,11 +237,8 @@ static int acpi_suspend_enter(suspend_state_t pm_state)
 		break;
 	}
 
-	/* If ACPI is not enabled by the BIOS, we need to enable it here. */
-	if (set_sci_en_on_resume)
-		acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);
-	else
-		acpi_enable();
+	/* This violates the spec but is required for bug compatibility. */
+	acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);
 
 	/* Reprogram control registers and execute _BFS */
 	acpi_leave_sleep_state_prep(acpi_state);
@@ -346,12 +327,6 @@ static int __init init_old_suspend_ordering(const struct dmi_system_id *d)
 	return 0;
 }
 
-static int __init init_set_sci_en_on_resume(const struct dmi_system_id *d)
-{
-	set_sci_en_on_resume = true;
-	return 0;
-}
-
 static struct dmi_system_id __initdata acpisleep_dmi_table[] = {
 	{
 	.callback = init_old_suspend_ordering,
@@ -370,22 +345,6 @@ static struct dmi_system_id __initdata acpisleep_dmi_table[] = {
 		},
 	},
 	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Apple MacBook 1,1",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Apple Computer, Inc."),
-		DMI_MATCH(DMI_PRODUCT_NAME, "MacBook1,1"),
-		},
-	},
-	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Apple MacMini 1,1",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Apple Computer, Inc."),
-		DMI_MATCH(DMI_PRODUCT_NAME, "Macmini1,1"),
-		},
-	},
-	{
 	.callback = init_old_suspend_ordering,
 	.ident = "Asus Pundit P1-AH2 (M2N8L motherboard)",
 	.matches = {
@@ -394,94 +353,6 @@ static struct dmi_system_id __initdata acpisleep_dmi_table[] = {
 		},
 	},
 	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Toshiba Satellite L300",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "Satellite L300"),
-		},
-	},
-	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Hewlett-Packard HP G7000 Notebook PC",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "HP G7000 Notebook PC"),
-		},
-	},
-	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Hewlett-Packard HP Pavilion dv3 Notebook PC",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion dv3 Notebook PC"),
-		},
-	},
-	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Hewlett-Packard Pavilion dv4",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion dv4"),
-		},
-	},
-	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Hewlett-Packard Pavilion dv7",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion dv7"),
-		},
-	},
-	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Hewlett-Packard Compaq Presario C700 Notebook PC",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "Compaq Presario C700 Notebook PC"),
-		},
-	},
-	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Hewlett-Packard Compaq Presario CQ40 Notebook PC",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
-		DMI_MATCH(DMI_PRODUCT_NAME, "Compaq Presario CQ40 Notebook PC"),
-		},
-	},
-	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Lenovo ThinkPad T410",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T410"),
-		},
-	},
-	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Lenovo ThinkPad T510",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T510"),
-		},
-	},
-	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Lenovo ThinkPad W510",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad W510"),
-		},
-	},
-	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Lenovo ThinkPad X201[s]",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
-		DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X201"),
-		},
-	},
-	{
 	.callback = init_old_suspend_ordering,
 	.ident = "Panasonic CF51-2L",
 	.matches = {
@@ -490,30 +361,6 @@ static struct dmi_system_id __initdata acpisleep_dmi_table[] = {
 		DMI_MATCH(DMI_BOARD_NAME, "CF51-2L"),
 		},
 	},
-	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Dell Studio 1558",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
-		DMI_MATCH(DMI_PRODUCT_NAME, "Studio 1558"),
-		},
-	},
-	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Dell Studio 1557",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
-		DMI_MATCH(DMI_PRODUCT_NAME, "Studio 1557"),
-		},
-	},
-	{
-	.callback = init_set_sci_en_on_resume,
-	.ident = "Dell Studio 1555",
-	.matches = {
-		DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
-		DMI_MATCH(DMI_PRODUCT_NAME, "Studio 1555"),
-		},
-	},
 	{},
 };
 #endif /* CONFIG_SUSPEND */
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index b926afe8c03e..87ca4913294c 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -251,7 +251,6 @@ int acpi_check_mem_region(resource_size_t start, resource_size_t n,
 void __init acpi_no_s4_hw_signature(void);
 void __init acpi_old_suspend_ordering(void);
 void __init acpi_s4_no_nvs(void);
-void __init acpi_set_sci_en_on_resume(void);
 #endif /* CONFIG_PM_SLEEP */
 
 struct acpi_osc_context {