13 files changed, 378 insertions, 102 deletions

diff --git a/Documentation/acpi/enumeration.txt b/Documentation/acpi/enumeration.txt
index 15dfce708ebf..b731b292e812 100644
--- a/Documentation/acpi/enumeration.txt
+++ b/Documentation/acpi/enumeration.txt
@@ -42,7 +42,7 @@ Adding ACPI support for an existing driver should be pretty
 straightforward. Here is the simplest example:
 
         #ifdef CONFIG_ACPI
-        static struct acpi_device_id mydrv_acpi_match[] = {
+        static const struct acpi_device_id mydrv_acpi_match[] = {
                 /* ACPI IDs here */
                 { }
         };
@@ -166,7 +166,7 @@ the platform device drivers. Below is an example where we add ACPI support
 to at25 SPI eeprom driver (this is meant for the above ACPI snippet):
 
         #ifdef CONFIG_ACPI
-        static struct acpi_device_id at25_acpi_match[] = {
+        static const struct acpi_device_id at25_acpi_match[] = {
                 { "AT25", 0 },
                 { },
         };
@@ -230,7 +230,7 @@ Below is an example of how to add ACPI support to the existing mpu3050
 input driver:
 
         #ifdef CONFIG_ACPI
-        static struct acpi_device_id mpu3050_acpi_match[] = {
+        static const struct acpi_device_id mpu3050_acpi_match[] = {
                 { "MPU3050", 0 },
                 { },
         };
@@ -359,3 +359,54 @@ the id should be set like:
 The ACPI id "XYZ0001" is then used to lookup an ACPI device directly under
 the MFD device and if found, that ACPI companion device is bound to the
 resulting child platform device.
+
+Device Tree namespace link device ID
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The Device Tree protocol uses device indentification based on the "compatible"
+property whose value is a string or an array of strings recognized as device
+identifiers by drivers and the driver core.  The set of all those strings may be
+regarded as a device indentification namespace analogous to the ACPI/PNP device
+ID namespace.  Consequently, in principle it should not be necessary to allocate
+a new (and arguably redundant) ACPI/PNP device ID for a devices with an existing
+identification string in the Device Tree (DT) namespace, especially if that ID
+is only needed to indicate that a given device is compatible with another one,
+presumably having a matching driver in the kernel already.
+
+In ACPI, the device identification object called _CID (Compatible ID) is used to
+list the IDs of devices the given one is compatible with, but those IDs must
+belong to one of the namespaces prescribed by the ACPI specification (see
+Section 6.1.2 of ACPI 6.0 for details) and the DT namespace is not one of them.
+Moreover, the specification mandates that either a _HID or an _ADR identificaion
+object be present for all ACPI objects representing devices (Section 6.1 of ACPI
+6.0).  For non-enumerable bus types that object must be _HID and its value must
+be a device ID from one of the namespaces prescribed by the specification too.
+
+The special DT namespace link device ID, PRP0001, provides a means to use the
+existing DT-compatible device identification in ACPI and to satisfy the above
+requirements following from the ACPI specification at the same time.  Namely,
+if PRP0001 is returned by _HID, the ACPI subsystem will look for the
+"compatible" property in the device object's _DSD and will use the value of that
+property to identify the corresponding device in analogy with the original DT
+device identification algorithm.  If the "compatible" property is not present
+or its value is not valid, the device will not be enumerated by the ACPI
+subsystem.  Otherwise, it will be enumerated automatically as a platform device
+(except when an I2C or SPI link from the device to its parent is present, in
+which case the ACPI core will leave the device enumeration to the parent's
+driver) and the identification strings from the "compatible" property value will
+be used to find a driver for the device along with the device IDs listed by _CID
+(if present).
+
+Analogously, if PRP0001 is present in the list of device IDs returned by _CID,
+the identification strings listed by the "compatible" property value (if present
+and valid) will be used to look for a driver matching the device, but in that
+case their relative priority with respect to the other device IDs listed by
+_HID and _CID depends on the position of PRP0001 in the _CID return package.
+Specifically, the device IDs returned by _HID and preceding PRP0001 in the _CID
+return package will be checked first.  Also in that case the bus type the device
+will be enumerated to depends on the device ID returned by _HID.
+
+It is valid to define device objects with a _HID returning PRP0001 and without
+the "compatible" property in the _DSD or a _CID as long as one of their
+ancestors provides a _DSD with a valid "compatible" property.  Such device
+objects are then simply regarded as additional "blocks" providing hierarchical
+configuration information to the driver of the composite ancestor device.
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 6726139bd289..10f879221821 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -179,11 +179,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
                         See also Documentation/power/runtime_pm.txt, pci=noacpi
 
-        acpi_rsdp=      [ACPI,EFI,KEXEC]
-                        Pass the RSDP address to the kernel, mostly used
-                        on machines running EFI runtime service to boot the
-                        second kernel for kdump.
-
         acpi_apic_instance=     [ACPI, IOAPIC]
                         Format: <int>
                         2: use 2nd APIC table, if available
@@ -197,6 +192,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         (e.g. thinkpad_acpi, sony_acpi, etc.) instead
                         of the ACPI video.ko driver.
 
+        acpica_no_return_repair [HW, ACPI]
+                        Disable AML predefined validation mechanism
+                        This mechanism can repair the evaluation result to make
+                        the return objects more ACPI specification compliant.
+                        This option is useful for developers to identify the
+                        root cause of an AML interpreter issue when the issue
+                        has something to do with the repair mechanism.
+
         acpi.debug_layer=       [HW,ACPI,ACPI_DEBUG]
         acpi.debug_level=       [HW,ACPI,ACPI_DEBUG]
                         Format: <int>
@@ -225,6 +228,22 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         unusable.  The "log_buf_len" parameter may be useful
                         if you need to capture more output.
 
+        acpi_enforce_resources= [ACPI]
+                        { strict | lax | no }
+                        Check for resource conflicts between native drivers
+                        and ACPI OperationRegions (SystemIO and SystemMemory
+                        only). IO ports and memory declared in ACPI might be
+                        used by the ACPI subsystem in arbitrary AML code and
+                        can interfere with legacy drivers.
+                        strict (default): access to resources claimed by ACPI
+                        is denied; legacy drivers trying to access reserved
+                        resources will fail to bind to device using them.
+                        lax: access to resources claimed by ACPI is allowed;
+                        legacy drivers trying to access reserved resources
+                        will bind successfully but a warning message is logged.
+                        no: ACPI OperationRegions are not marked as reserved,
+                        no further checks are performed.
+
         acpi_force_table_verification   [HW,ACPI]
                         Enable table checksum verification during early stage.
                         By default, this is disabled due to x86 early mapping
@@ -253,6 +272,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         This feature is enabled by default.
                         This option allows to turn off the feature.
 
+        acpi_no_memhotplug [ACPI] Disable memory hotplug.  Useful for kdump
+                           kernels.
+
         acpi_no_static_ssdt     [HW,ACPI]
                         Disable installation of static SSDTs at early boot time
                         By default, SSDTs contained in the RSDT/XSDT will be
@@ -263,13 +285,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         dynamic table installation which will install SSDT
                         tables to /sys/firmware/acpi/tables/dynamic.
 
-        acpica_no_return_repair [HW, ACPI]
-                        Disable AML predefined validation mechanism
-                        This mechanism can repair the evaluation result to make
-                        the return objects more ACPI specification compliant.
-                        This option is useful for developers to identify the
-                        root cause of an AML interpreter issue when the issue
-                        has something to do with the repair mechanism.
+        acpi_rsdp=      [ACPI,EFI,KEXEC]
+                        Pass the RSDP address to the kernel, mostly used
+                        on machines running EFI runtime service to boot the
+                        second kernel for kdump.
 
         acpi_os_name=   [HW,ACPI] Tell ACPI BIOS the name of the OS
                         Format: To spoof as Windows 98: ="Microsoft Windows"
@@ -365,25 +384,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         Use timer override. For some broken Nvidia NF5 boards
                         that require a timer override, but don't have HPET
 
-        acpi_enforce_resources= [ACPI]
-                        { strict | lax | no }
-                        Check for resource conflicts between native drivers
-                        and ACPI OperationRegions (SystemIO and SystemMemory
-                        only). IO ports and memory declared in ACPI might be
-                        used by the ACPI subsystem in arbitrary AML code and
-                        can interfere with legacy drivers.
-                        strict (default): access to resources claimed by ACPI
-                        is denied; legacy drivers trying to access reserved
-                        resources will fail to bind to device using them.
-                        lax: access to resources claimed by ACPI is allowed;
-                        legacy drivers trying to access reserved resources
-                        will bind successfully but a warning message is logged.
-                        no: ACPI OperationRegions are not marked as reserved,
-                        no further checks are performed.
-
-        acpi_no_memhotplug [ACPI] Disable memory hotplug.  Useful for kdump
-                           kernels.
-
         add_efi_memmap  [EFI; X86] Include EFI memory map in
                         kernel's map of available physical RAM.
 
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index ab2cbb51c6aa..16da18597def 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -62,7 +62,7 @@ config ACPI_SLEEP
 
 config ACPI_PROCFS_POWER
         bool "Deprecated power /proc/acpi directories"
-        depends on PROC_FS
+        depends on X86 && PROC_FS
         help
           For backwards compatibility, this option allows
           deprecated power /proc/acpi/ directories to exist, even when
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index c412fdb28d34..513e7230e3d0 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -470,6 +470,16 @@ static int __init acpi_bus_init_irq(void)
         return 0;
 }
 
+/**
+ * acpi_early_init - Initialize ACPICA and populate the ACPI namespace.
+ *
+ * The ACPI tables are accessible after this, but the handling of events has not
+ * been initialized and the global lock is not available yet, so AML should not
+ * be executed at this point.
+ *
+ * Doing this before switching the EFI runtime services to virtual mode allows
+ * the EfiBootServices memory to be freed slightly earlier on boot.
+ */
 void __init acpi_early_init(void)
 {
         acpi_status status;
@@ -533,26 +543,42 @@ void __init acpi_early_init(void)
                 acpi_gbl_FADT.sci_interrupt = acpi_sci_override_gsi;
         }
 #endif
+        return;
+
+ error0:
+        disable_acpi();
+}
+
+/**
+ * acpi_subsystem_init - Finalize the early initialization of ACPI.
+ *
+ * Switch over the platform to the ACPI mode (if possible), initialize the
+ * handling of ACPI events, install the interrupt and global lock handlers.
+ *
+ * Doing this too early is generally unsafe, but at the same time it needs to be
+ * done before all things that really depend on ACPI.  The right spot appears to
+ * be before finalizing the EFI initialization.
+ */
+void __init acpi_subsystem_init(void)
+{
+        acpi_status status;
+
+        if (acpi_disabled)
+                return;
 
         status = acpi_enable_subsystem(~ACPI_NO_ACPI_ENABLE);
         if (ACPI_FAILURE(status)) {
                 printk(KERN_ERR PREFIX "Unable to enable ACPI\n");
-                goto error0;
+                disable_acpi();
+        } else {
+                /*
+                 * If the system is using ACPI then we can be reasonably
+                 * confident that any regulators are managed by the firmware
+                 * so tell the regulator core it has everything it needs to
+                 * know.
+                 */
+                regulator_has_full_constraints();
         }
-
-        /*
-         * If the system is using ACPI then we can be reasonably
-         * confident that any regulators are managed by the firmware
-         * so tell the regulator core it has everything it needs to
-         * know.
-         */
-        regulator_has_full_constraints();
-
-        return;
-
-      error0:
-        disable_acpi();
-        return;
 }
 
 static int __init acpi_bus_init(void)
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index ba4a61e964be..d93628c65661 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -191,6 +191,8 @@ bool acpi_osi_is_win8(void);
 /*--------------------------------------------------------------------------
                                 Device properties
   -------------------------------------------------------------------------- */
+#define ACPI_DT_NAMESPACE_HID   "PRP0001"
+
 void acpi_init_properties(struct acpi_device *adev);
 void acpi_free_properties(struct acpi_device *adev);
 
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 7ccba395c9dd..5226a8b921ae 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -175,11 +175,7 @@ static void __init acpi_request_region (struct acpi_generic_address *gas,
         if (!addr || !length)
                 return;
 
-        /* Resources are never freed */
-        if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO)
-                request_region(addr, length, desc);
-        else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
-                request_mem_region(addr, length, desc);
+        acpi_reserve_region(addr, length, gas->space_id, 0, desc);
 }
 
 static void __init acpi_reserve_resources(void)
diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
index 0d083736e25b..7836e2e980f4 100644
--- a/drivers/acpi/property.c
+++ b/drivers/acpi/property.c
@@ -79,50 +79,51 @@ static bool acpi_properties_format_valid(const union acpi_object *properties)
 static void acpi_init_of_compatible(struct acpi_device *adev)
 {
         const union acpi_object *of_compatible;
-        struct acpi_hardware_id *hwid;
-        bool acpi_of = false;
         int ret;
 
-        /*
-         * Check if the special PRP0001 ACPI ID is present and in that
-         * case we fill in Device Tree compatible properties for this
-         * device.
-         */
-        list_for_each_entry(hwid, &adev->pnp.ids, list) {
-                if (!strcmp(hwid->id, "PRP0001")) {
-                        acpi_of = true;
-                        break;
-                }
-        }
-
-        if (!acpi_of)
-                return;
-
         ret = acpi_dev_get_property_array(adev, "compatible", ACPI_TYPE_STRING,
                                           &of_compatible);
         if (ret) {
                 ret = acpi_dev_get_property(adev, "compatible",
                                             ACPI_TYPE_STRING, &of_compatible);
                 if (ret) {
-                        acpi_handle_warn(adev->handle,
-                                         "PRP0001 requires compatible property\n");
+                        if (adev->parent
+                            && adev->parent->flags.of_compatible_ok)
+                                goto out;
+
                         return;
                 }
         }
         adev->data.of_compatible = of_compatible;
+
+ out:
+        adev->flags.of_compatible_ok = 1;
 }
 
 void acpi_init_properties(struct acpi_device *adev)
 {
         struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
+        bool acpi_of = false;
+        struct acpi_hardware_id *hwid;
         const union acpi_object *desc;
         acpi_status status;
         int i;
 
+        /*
+         * Check if ACPI_DT_NAMESPACE_HID is present and inthat case we fill in
+         * Device Tree compatible properties for this device.
+         */
+        list_for_each_entry(hwid, &adev->pnp.ids, list) {
+                if (!strcmp(hwid->id, ACPI_DT_NAMESPACE_HID)) {
+                        acpi_of = true;
+                        break;
+                }
+        }
+
         status = acpi_evaluate_object_typed(adev->handle, "_DSD", NULL, &buf,
                                             ACPI_TYPE_PACKAGE);
         if (ACPI_FAILURE(status))
-                return;
+                goto out;
 
         desc = buf.pointer;
         if (desc->package.count % 2)
@@ -156,13 +157,20 @@ void acpi_init_properties(struct acpi_device *adev)
                 adev->data.pointer = buf.pointer;
                 adev->data.properties = properties;
 
-                acpi_init_of_compatible(adev);
-                return;
+                if (acpi_of)
+                        acpi_init_of_compatible(adev);
+
+                goto out;
         }
 
  fail:
-        dev_warn(&adev->dev, "Returned _DSD data is not valid, skipping\n");
+        dev_dbg(&adev->dev, "Returned _DSD data is not valid, skipping\n");
         ACPI_FREE(buf.pointer);
+
+ out:
+        if (acpi_of && !adev->flags.of_compatible_ok)
+                acpi_handle_info(adev->handle,
+                         ACPI_DT_NAMESPACE_HID " requires 'compatible' property\n");
 }
 
 void acpi_free_properties(struct acpi_device *adev)
diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index 8244f013f210..fcb7807ea8b7 100644
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -26,6 +26,7 @@
 #include <linux/device.h>
 #include <linux/export.h>
 #include <linux/ioport.h>
+#include <linux/list.h>
 #include <linux/slab.h>
 
 #ifdef CONFIG_X86
@@ -621,3 +622,162 @@ int acpi_dev_filter_resource_type(struct acpi_resource *ares,
         return (type & types) ? 0 : 1;
 }
 EXPORT_SYMBOL_GPL(acpi_dev_filter_resource_type);
+
+struct reserved_region {
+        struct list_head node;
+        u64 start;
+        u64 end;
+};
+
+static LIST_HEAD(reserved_io_regions);
+static LIST_HEAD(reserved_mem_regions);
+
+static int request_range(u64 start, u64 end, u8 space_id, unsigned long flags,
+                         char *desc)
+{
+        unsigned int length = end - start + 1;
+        struct resource *res;
+
+        res = space_id == ACPI_ADR_SPACE_SYSTEM_IO ?
+                request_region(start, length, desc) :
+                request_mem_region(start, length, desc);
+        if (!res)
+                return -EIO;
+
+        res->flags &= ~flags;
+        return 0;
+}
+
+static int add_region_before(u64 start, u64 end, u8 space_id,
+                             unsigned long flags, char *desc,
+                             struct list_head *head)
+{
+        struct reserved_region *reg;
+        int error;
+
+        reg = kmalloc(sizeof(*reg), GFP_KERNEL);
+        if (!reg)
+                return -ENOMEM;
+
+        error = request_range(start, end, space_id, flags, desc);
+        if (error)
+                return error;
+
+        reg->start = start;
+        reg->end = end;
+        list_add_tail(&reg->node, head);
+        return 0;
+}
+
+/**
+ * acpi_reserve_region - Reserve an I/O or memory region as a system resource.
+ * @start: Starting address of the region.
+ * @length: Length of the region.
+ * @space_id: Identifier of address space to reserve the region from.
+ * @flags: Resource flags to clear for the region after requesting it.
+ * @desc: Region description (for messages).
+ *
+ * Reserve an I/O or memory region as a system resource to prevent others from
+ * using it.  If the new region overlaps with one of the regions (in the given
+ * address space) already reserved by this routine, only the non-overlapping
+ * parts of it will be reserved.
+ *
+ * Returned is either 0 (success) or a negative error code indicating a resource
+ * reservation problem.  It is the code of the first encountered error, but the
+ * routine doesn't abort until it has attempted to request all of the parts of
+ * the new region that don't overlap with other regions reserved previously.
+ *
+ * The resources requested by this routine are never released.
+ */
+int acpi_reserve_region(u64 start, unsigned int length, u8 space_id,
+                        unsigned long flags, char *desc)
+{
+        struct list_head *regions;
+        struct reserved_region *reg;
+        u64 end = start + length - 1;
+        int ret = 0, error = 0;
+
+        if (space_id == ACPI_ADR_SPACE_SYSTEM_IO)
+                regions = &reserved_io_regions;
+        else if (space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+                regions = &reserved_mem_regions;
+        else
+                return -EINVAL;
+
+        if (list_empty(regions))
+                return add_region_before(start, end, space_id, flags, desc, regions);
+
+        list_for_each_entry(reg, regions, node)
+                if (reg->start == end + 1) {
+                        /* The new region can be prepended to this one. */
+                        ret = request_range(start, end, space_id, flags, desc);
+                        if (!ret)
+                                reg->start = start;
+
+                        return ret;
+                } else if (reg->start > end) {
+                        /* No overlap.  Add the new region here and get out. */
+                        return add_region_before(start, end, space_id, flags,
+                                                 desc, &reg->node);
+                } else if (reg->end == start - 1) {
+                        goto combine;
+                } else if (reg->end >= start) {
+                        goto overlap;
+                }
+
+        /* The new region goes after the last existing one. */
+        return add_region_before(start, end, space_id, flags, desc, regions);
+
+ overlap:
+        /*
+         * The new region overlaps an existing one.
+         *
+         * The head part of the new region immediately preceding the existing
+         * overlapping one can be combined with it right away.
+         */
+        if (reg->start > start) {
+                error = request_range(start, reg->start - 1, space_id, flags, desc);
+                if (error)
+                        ret = error;
+                else
+                        reg->start = start;
+        }
+
+ combine:
+        /*
+         * The new region is adjacent to an existing one.  If it extends beyond
+         * that region all the way to the next one, it is possible to combine
+         * all three of them.
+         */
+        while (reg->end < end) {
+                struct reserved_region *next = NULL;
+                u64 a = reg->end + 1, b = end;
+
+                if (!list_is_last(&reg->node, regions)) {
+                        next = list_next_entry(reg, node);
+                        if (next->start <= end)
+                                b = next->start - 1;
+                }
+                error = request_range(a, b, space_id, flags, desc);
+                if (!error) {
+                        if (next && next->start == b + 1) {
+                                reg->end = next->end;
+                                list_del(&next->node);
+                                kfree(next);
+                        } else {
+                                reg->end = end;
+                                break;
+                        }
+                } else if (next) {
+                        if (!ret)
+                                ret = error;
+
+                        reg = next;
+                } else {
+                        break;
+                }
+        }
+
+        return ret ? ret : error;
+}
+EXPORT_SYMBOL_GPL(acpi_reserve_region);
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 03141aa4ea95..0a099917a006 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -135,12 +135,13 @@ static int create_pnp_modalias(struct acpi_device *acpi_dev, char *modalias,
         struct acpi_hardware_id *id;
 
         /*
-         * Since we skip PRP0001 from the modalias below, 0 should be returned
-         * if PRP0001 is the only ACPI/PNP ID in the device's list.
+         * Since we skip ACPI_DT_NAMESPACE_HID from the modalias below, 0 should
+         * be returned if ACPI_DT_NAMESPACE_HID is the only ACPI/PNP ID in the
+         * device's list.
          */
         count = 0;
         list_for_each_entry(id, &acpi_dev->pnp.ids, list)
-                if (strcmp(id->id, "PRP0001"))
+                if (strcmp(id->id, ACPI_DT_NAMESPACE_HID))
                         count++;
 
         if (!count)
@@ -153,7 +154,7 @@ static int create_pnp_modalias(struct acpi_device *acpi_dev, char *modalias,
         size -= len;
 
         list_for_each_entry(id, &acpi_dev->pnp.ids, list) {
-                if (!strcmp(id->id, "PRP0001"))
+                if (!strcmp(id->id, ACPI_DT_NAMESPACE_HID))
                         continue;
 
                 count = snprintf(&modalias[len], size, "%s:", id->id);
@@ -177,7 +178,8 @@ static int create_pnp_modalias(struct acpi_device *acpi_dev, char *modalias,
  * @size: Size of the buffer.
  *
  * Expose DT compatible modalias as of:NnameTCcompatible.  This function should
- * only be called for devices having PRP0001 in their list of ACPI/PNP IDs.
+ * only be called for devices having ACPI_DT_NAMESPACE_HID in their list of
+ * ACPI/PNP IDs.
  */
 static int create_of_modalias(struct acpi_device *acpi_dev, char *modalias,
                               int size)
@@ -980,9 +982,9 @@ static void acpi_device_remove_files(struct acpi_device *dev)
  * @adev: ACPI device object to match.
  * @of_match_table: List of device IDs to match against.
  *
- * If @dev has an ACPI companion which has the special PRP0001 device ID in its
- * list of identifiers and a _DSD object with the "compatible" property, use
- * that property to match against the given list of identifiers.
+ * If @dev has an ACPI companion which has ACPI_DT_NAMESPACE_HID in its list of
+ * identifiers and a _DSD object with the "compatible" property, use that
+ * property to match against the given list of identifiers.
  */
 static bool acpi_of_match_device(struct acpi_device *adev,
                                  const struct of_device_id *of_match_table)
@@ -1038,14 +1040,14 @@ static const struct acpi_device_id *__acpi_match_device(
                                 return id;
 
                 /*
-                 * Next, check the special "PRP0001" ID and try to match the
+                 * Next, check ACPI_DT_NAMESPACE_HID and try to match the
                  * "compatible" property if found.
                  *
                  * The id returned by the below is not valid, but the only
                  * caller passing non-NULL of_ids here is only interested in
                  * whether or not the return value is NULL.
                  */
-                if (!strcmp("PRP0001", hwid->id)
+                if (!strcmp(ACPI_DT_NAMESPACE_HID, hwid->id)
                     && acpi_of_match_device(device, of_ids))
                         return id;
         }
@@ -1671,7 +1673,7 @@ static int acpi_bus_extract_wakeup_device_power_package(acpi_handle handle,
 
 static void acpi_wakeup_gpe_init(struct acpi_device *device)
 {
-        struct acpi_device_id button_device_ids[] = {
+        static const struct acpi_device_id button_device_ids[] = {
                 {"PNP0C0C", 0},
                 {"PNP0C0D", 0},
                 {"PNP0C0E", 0},
@@ -2405,7 +2407,7 @@ static void acpi_default_enumeration(struct acpi_device *device)
 }
 
 static const struct acpi_device_id generic_device_ids[] = {
-        {"PRP0001", },
+        {ACPI_DT_NAMESPACE_HID, },
         {"", },
 };
 
@@ -2413,8 +2415,8 @@ static int acpi_generic_device_attach(struct acpi_device *adev,
                                       const struct acpi_device_id *not_used)
 {
         /*
-         * Since PRP0001 is the only ID handled here, the test below can be
-         * unconditional.
+         * Since ACPI_DT_NAMESPACE_HID is the only ID handled here, the test
+         * below can be unconditional.
          */
         if (adev->data.of_compatible)
                 acpi_default_enumeration(adev);
diff --git a/drivers/pnp/system.c b/drivers/pnp/system.c
index 49c1720df59a..515f33882ab8 100644
--- a/drivers/pnp/system.c
+++ b/drivers/pnp/system.c
@@ -7,6 +7,7 @@
  *      Bjorn Helgaas <bjorn.helgaas@hp.com>
  */
 
+#include <linux/acpi.h>
 #include <linux/pnp.h>
 #include <linux/device.h>
 #include <linux/init.h>
@@ -22,25 +23,41 @@ static const struct pnp_device_id pnp_dev_table[] = {
         {"", 0}
 };
 
+#ifdef CONFIG_ACPI
+static bool __reserve_range(u64 start, unsigned int length, bool io, char *desc)
+{
+        u8 space_id = io ? ACPI_ADR_SPACE_SYSTEM_IO : ACPI_ADR_SPACE_SYSTEM_MEMORY;
+        return !acpi_reserve_region(start, length, space_id, IORESOURCE_BUSY, desc);
+}
+#else
+static bool __reserve_range(u64 start, unsigned int length, bool io, char *desc)
+{
+        struct resource *res;
+
+        res = io ? request_region(start, length, desc) :
+                request_mem_region(start, length, desc);
+        if (res) {
+                res->flags &= ~IORESOURCE_BUSY;
+                return true;
+        }
+        return false;
+}
+#endif
+
 static void reserve_range(struct pnp_dev *dev, struct resource *r, int port)
 {
         char *regionid;
         const char *pnpid = dev_name(&dev->dev);
         resource_size_t start = r->start, end = r->end;
-        struct resource *res;
+        bool reserved;
 
         regionid = kmalloc(16, GFP_KERNEL);
         if (!regionid)
                 return;
 
         snprintf(regionid, 16, "pnp %s", pnpid);
-        if (port)
-                res = request_region(start, end - start + 1, regionid);
-        else
-                res = request_mem_region(start, end - start + 1, regionid);
-        if (res)
-                res->flags &= ~IORESOURCE_BUSY;
-        else
+        reserved = __reserve_range(start, end - start + 1, !!port, regionid);
+        if (!reserved)
                 kfree(regionid);
 
         /*
@@ -49,7 +66,7 @@ static void reserve_range(struct pnp_dev *dev, struct resource *r, int port)
          * have double reservations.
          */
         dev_info(&dev->dev, "%pR %s reserved\n", r,
-                 res ? "has been" : "could not be");
+                 reserved ? "has been" : "could not be");
 }
 
 static void reserve_resources_of_dev(struct pnp_dev *dev)
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 8de4fa90e8c4..da079976971f 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -208,7 +208,8 @@ struct acpi_device_flags {
         u32 visited:1;
         u32 hotplug_notify:1;
         u32 is_dock_station:1;
-        u32 reserved:23;
+        u32 of_compatible_ok:1;
+        u32 reserved:22;
 };
 
 /* File System */
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index e4da5e35e29c..5da2d2e9d38e 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -332,6 +332,9 @@ int acpi_check_region(resource_size_t start, resource_size_t n,
 
 int acpi_resources_are_enforced(void);
 
+int acpi_reserve_region(u64 start, unsigned int length, u8 space_id,
+                        unsigned long flags, char *desc);
+
 #ifdef CONFIG_HIBERNATION
 void __init acpi_no_s4_hw_signature(void);
 #endif
@@ -440,6 +443,7 @@ extern acpi_status acpi_pci_osc_control_set(acpi_handle handle,
 #define ACPI_OST_SC_INSERT_NOT_SUPPORTED        0x82
 
 extern void acpi_early_init(void);
+extern void acpi_subsystem_init(void);
 
 extern int acpi_nvs_register(__u64 start, __u64 size);
 
@@ -494,6 +498,7 @@ static inline const char *acpi_dev_name(struct acpi_device *adev)
 }
 
 static inline void acpi_early_init(void) { }
+static inline void acpi_subsystem_init(void) { }
 
 static inline int early_acpi_boot_init(void)
 {
@@ -525,6 +530,13 @@ static inline int acpi_check_region(resource_size_t start, resource_size_t n,
         return 0;
 }
 
+static inline int acpi_reserve_region(u64 start, unsigned int length,
+                                      u8 space_id, unsigned long flags,
+                                      char *desc)
+{
+        return -ENXIO;
+}
+
 struct acpi_table_header;
 static inline int acpi_table_parse(char *id,
                                 int (*handler)(struct acpi_table_header *))
diff --git a/init/main.c b/init/main.c
index 2115055faeac..2a89545e0a5d 100644
--- a/init/main.c
+++ b/init/main.c
@@ -664,6 +664,7 @@ asmlinkage __visible void __init start_kernel(void)
 
         check_bugs();
 
+        acpi_subsystem_init();
         sfi_init_late();
 
         if (efi_enabled(EFI_RUNTIME_SERVICES)) {