[PATCH] Driver Core: remove driver model detach_state

The driver model has a "detach_state" mechanism that:

 - Has never been used by any in-kernel drive;
 - Is superfluous, since driver remove() methods can do the same thing;
 - Became buggy when the suspend() parameter changed semantics and type;
 - Could self-deadlock when called from certain suspend contexts;
 - Is effectively wasted documentation, object code, and headspace.

This removes that "detach_state" mechanism; net code shrink, as well
as a per-device saving in the driver model and sysfs.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

10 files changed, 5 insertions, 113 deletions

diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt
index e97d024eae77..988a62fae11f 100644
--- a/Documentation/filesystems/sysfs-pci.txt
+++ b/Documentation/filesystems/sysfs-pci.txt
@@ -7,7 +7,6 @@ that support it.  For example, a given bus might look like this:
      |-- 0000:17:00.0
      |   |-- class
      |   |-- config
-     |   |-- detach_state
      |   |-- device
      |   |-- irq
      |   |-- local_cpus
@@ -19,7 +18,7 @@ that support it.  For example, a given bus might look like this:
      |   |-- subsystem_device
      |   |-- subsystem_vendor
      |   `-- vendor
-     `-- detach_state
+     `-- ...
 
 The topmost element describes the PCI domain and bus number.  In this case,
 the domain number is 0000 and the bus number is 17 (both values are in hex).
@@ -31,7 +30,6 @@ files, each with their own function.
        ----                --------
        class               PCI class (ascii, ro)
        config              PCI config space (binary, rw)
-       detach_state        connection status (bool, rw)
        device              PCI device (ascii, ro)
        irq                 IRQ number (ascii, ro)
        local_cpus          nearby CPU mask (cpumask, ro)
@@ -85,4 +83,4 @@ useful return codes should be provided.
 
 Legacy resources are protected by the HAVE_PCI_LEGACY define.  Platforms
 wishing to support legacy functionality should define it and provide
-pci_legacy_read, pci_legacy_write and pci_mmap_legacy_page_range functions.
\ No newline at end of file
+pci_legacy_read, pci_legacy_write and pci_mmap_legacy_page_range functions.
diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt
index 5d4ae9a39f1d..f987afe43e28 100644
--- a/Documentation/power/devices.txt
+++ b/Documentation/power/devices.txt
@@ -207,27 +207,6 @@ SYSTEM_SHUTDOWN, I do not understand this one too much. probably event
 #READY_AFTER_RESUME
 #
 
-Driver Detach Power Management
-
-The kernel now supports the ability to place a device in a low-power
-state when it is detached from its driver, which happens when its
-module is removed. 
-
-Each device contains a 'detach_state' file in its sysfs directory
-which can be used to control this state. Reading from this file
-displays what the current detach state is set to. This is 0 (On) by
-default. A user may write a positive integer value to this file in the
-range of 1-4 inclusive. 
-
-A value of 1-3 will indicate the device should be placed in that
-low-power state, which will cause ->suspend() to be called for that
-device. A value of 4 indicates that the device should be shutdown, so
-->shutdown() will be called for that device. 
-
-The driver is responsible for reinitializing the device when the
-module is re-inserted during it's ->probe() (or equivalent) method. 
-The driver core will not call any extra functions when binding the
-device to the driver. 
 
 pm_message_t meaning
 
diff --git a/Documentation/powerpc/hvcs.txt b/Documentation/powerpc/hvcs.txt
index c0a62e116e6e..dca75cbda6f8 100644
--- a/Documentation/powerpc/hvcs.txt
+++ b/Documentation/powerpc/hvcs.txt
@@ -347,8 +347,8 @@ address that is created by firmware.  An example vty-server sysfs entry
 looks like the following:
 
         Pow5:/sys/bus/vio/drivers/hvcs/30000004 # ls
-        .   current_vty   devspec  name          partner_vtys
-        ..  detach_state  index    partner_clcs  vterm_state
+        .   current_vty   devspec       name          partner_vtys
+        ..  index         partner_clcs  vterm_state
 
 Each entry is provided, by default with a "name" attribute.  Reading the
 "name" attribute will reveal the device type as shown in the following
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 6662b545e0a9..a47928a2e575 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -1,6 +1,6 @@
 # Makefile for the Linux device tree
 
-obj-y                   := core.o sys.o interface.o bus.o \
+obj-y                   := core.o sys.o bus.o \
                            driver.o class.o class_simple.o platform.o \
                            cpu.o firmware.o init.o map.o dmapool.o \
                            attribute_container.o transport_class.o
diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 2b3902c867da..3cb04bb04c2b 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -390,7 +390,6 @@ void device_release_driver(struct device * dev)
                 sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
                 sysfs_remove_link(&dev->kobj, "driver");
                 list_del_init(&dev->driver_list);
-                device_detach_shutdown(dev);
                 if (drv->remove)
                         drv->remove(dev);
                 dev->driver = NULL;
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 268a9c8d168b..d21eb7744496 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -31,8 +31,6 @@ int (*platform_notify_remove)(struct device * dev) = NULL;
 #define to_dev(obj) container_of(obj, struct device, kobj)
 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
 
-extern struct attribute * dev_default_attrs[];
-
 static ssize_t
 dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
 {
@@ -89,7 +87,6 @@ static void device_release(struct kobject * kobj)
 static struct kobj_type ktype_device = {
         .release        = device_release,
         .sysfs_ops      = &dev_sysfs_ops,
-        .default_attrs  = dev_default_attrs,
 };
 
 
diff --git a/drivers/base/interface.c b/drivers/base/interface.c
deleted file mode 100644
index bd515843a0cb..000000000000
--- a/drivers/base/interface.c
+++ /dev/null
@@ -1,51 +0,0 @@
-/*
- * drivers/base/interface.c - common driverfs interface that's exported to
- *      the world for all devices.
- *
- * Copyright (c) 2002-3 Patrick Mochel
- * Copyright (c) 2002-3 Open Source Development Labs
- *
- * This file is released under the GPLv2
- *
- */
-
-#include <linux/device.h>
-#include <linux/err.h>
-#include <linux/stat.h>
-#include <linux/string.h>
-
-/**
- *      detach_state - control the default power state for the device.
- *
- *      This is the state the device enters when it's driver module is
- *      unloaded. The value is an unsigned integer, in the range of 0-4.
- *      '0' indicates 'On', so no action will be taken when the driver is
- *      unloaded. This is the default behavior.
- *      '4' indicates 'Off', meaning the driver core will call the driver's
- *      shutdown method to quiesce the device.
- *      1-3 indicate a low-power state for the device to enter via the
- *      driver's suspend method.
- */
-
-static ssize_t detach_show(struct device * dev, char * buf)
-{
-        return sprintf(buf, "%u\n", dev->detach_state);
-}
-
-static ssize_t detach_store(struct device * dev, const char * buf, size_t n)
-{
-        u32 state;
-        state = simple_strtoul(buf, NULL, 10);
-        if (state > 4)
-                return -EINVAL;
-        dev->detach_state = state;
-        return n;
-}
-
-static DEVICE_ATTR(detach_state, 0644, detach_show, detach_store);
-
-
-struct attribute * dev_default_attrs[] = {
-        &dev_attr_detach_state.attr,
-        NULL,
-};
diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index e5eda746f2a6..2e700d795cf1 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -1,18 +1,7 @@
-
-
-enum {
-        DEVICE_PM_ON,
-        DEVICE_PM1,
-        DEVICE_PM2,
-        DEVICE_PM3,
-        DEVICE_PM_OFF,
-};
-
 /*
  * shutdown.c
  */
 
-extern int device_detach_shutdown(struct device *);
 extern void device_shutdown(void);
 
 
diff --git a/drivers/base/power/shutdown.c b/drivers/base/power/shutdown.c
index 97979901c149..f50a08be424b 100644
--- a/drivers/base/power/shutdown.c
+++ b/drivers/base/power/shutdown.c
@@ -19,22 +19,6 @@
 extern struct subsystem devices_subsys;
 
 
-int device_detach_shutdown(struct device * dev)
-{
-        if (!dev->detach_state)
-                return 0;
-
-        if (dev->detach_state == DEVICE_PM_OFF) {
-                if (dev->driver && dev->driver->shutdown) {
-                        dev_dbg(dev, "shutdown\n");
-                        dev->driver->shutdown(dev);
-                }
-                return 0;
-        }
-        return dpm_runtime_suspend(dev, dev->detach_state);
-}
-
-
 /**
  * We handle system devices differently - we suspend and shut them
  * down last and resume them first. That way, we don't do anything stupid like
diff --git a/include/linux/device.h b/include/linux/device.h
index cf470459fa69..df94c0de53f2 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -273,9 +273,6 @@ struct device {
                                            BIOS data relevant to device) */
         struct dev_pm_info      power;
 
-        u32             detach_state;   /* State to enter when device is
-                                           detached from its driver. */
-
         u64             *dma_mask;      /* dma mask (if dma'able device) */
         u64             coherent_dma_mask;/* Like dma_mask, but for
                                              alloc_coherent mappings as