3 files changed, 70 insertions, 2 deletions

diff --git a/Documentation/ABI/testing/sysfs-devices-firmware_node b/Documentation/ABI/testing/sysfs-devices-firmware_node
new file mode 100644
index 000000000000..46badc9ea284
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices-firmware_node
@@ -0,0 +1,17 @@
+What:           /sys/devices/.../firmware_node/
+Date:           September 2012
+Contact:        <>
+Description:
+                The /sys/devices/.../firmware_node directory contains attributes
+                allowing the user space to check and modify some firmware
+                related properties of given device.
+
+What:           /sys/devices/.../firmware_node/description
+Date:           September 2012
+Contact:        Lance Ortiz <lance.ortiz@hp.com>
+Description:
+                The /sys/devices/.../firmware/description attribute contains a string
+                that describes the device as provided by the _STR method in the ACPI
+                namespace.  This attribute is read-only.  If the device does not have
+                an _STR method associated with it in the ACPI namespace, this
+                attribute is not present.
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index d1ecca2b641a..04302835723d 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -10,6 +10,7 @@
 #include <linux/signal.h>
 #include <linux/kthread.h>
 #include <linux/dmi.h>
+#include <linux/nls.h>
 
 #include <acpi/acpi_drivers.h>
 
@@ -232,8 +233,35 @@ end:
 }
 static DEVICE_ATTR(path, 0444, acpi_device_path_show, NULL);
 
+/* sysfs file that shows description text from the ACPI _STR method */
+static ssize_t description_show(struct device *dev,
+                                struct device_attribute *attr,
+                                char *buf) {
+        struct acpi_device *acpi_dev = to_acpi_device(dev);
+        int result;
+
+        if (acpi_dev->pnp.str_obj == NULL)
+                return 0;
+
+        /*
+         * The _STR object contains a Unicode identifier for a device.
+         * We need to convert to utf-8 so it can be displayed.
+         */
+        result = utf16s_to_utf8s(
+                (wchar_t *)acpi_dev->pnp.str_obj->buffer.pointer,
+                acpi_dev->pnp.str_obj->buffer.length,
+                UTF16_LITTLE_ENDIAN, buf,
+                PAGE_SIZE);
+
+        buf[result++] = '\n';
+
+        return result;
+}
+static DEVICE_ATTR(description, 0444, description_show, NULL);
+
 static int acpi_device_setup_files(struct acpi_device *dev)
 {
+        struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
         acpi_status status;
         acpi_handle temp;
         int result = 0;
@@ -257,6 +285,21 @@ static int acpi_device_setup_files(struct acpi_device *dev)
                         goto end;
         }
 
+        /*
+         * If device has _STR, 'description' file is created
+         */
+        status = acpi_get_handle(dev->handle, "_STR", &temp);
+        if (ACPI_SUCCESS(status)) {
+                status = acpi_evaluate_object(dev->handle, "_STR",
+                                        NULL, &buffer);
+                if (ACPI_FAILURE(status))
+                        buffer.pointer = NULL;
+                dev->pnp.str_obj = buffer.pointer;
+                result = device_create_file(&dev->dev, &dev_attr_description);
+                if (result)
+                        goto end;
+        }
+
         /*
          * If device has _EJ0, 'eject' file is created that is used to trigger
          * hot-removal function from userland.
@@ -274,8 +317,15 @@ static void acpi_device_remove_files(struct acpi_device *dev)
         acpi_handle temp;
 
         /*
-         * If device has _EJ0, 'eject' file is created that is used to trigger
-         * hot-removal function from userland.
+         * If device has _STR, remove 'description' file
+         */
+        status = acpi_get_handle(dev->handle, "_STR", &temp);
+        if (ACPI_SUCCESS(status)) {
+                kfree(dev->pnp.str_obj);
+                device_remove_file(&dev->dev, &dev_attr_description);
+        }
+        /*
+         * If device has _EJ0, remove 'eject' file.
          */
         status = acpi_get_handle(dev->handle, "_EJ0", &temp);
         if (ACPI_SUCCESS(status))
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index bde976ee068d..3eb9de318824 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -208,6 +208,7 @@ struct acpi_device_pnp {
         struct list_head ids;           /* _HID and _CIDs */
         acpi_device_name device_name;   /* Driver-determined */
         acpi_device_class device_class; /*        "          */
+        union acpi_object *str_obj;     /* unicode string for _STR method */
 };
 
 #define acpi_device_bid(d)      ((d)->pnp.bus_id)