drivers/gpu/drm/drm_stub.c - kernel/msm-4.9 - Gitiles

 /**
  * \file drm_stub.h
  * Stub support
  *
  * \author Rickard E. (Rik) Faith <faith@valinux.com>
  */

 /*
  * Created: Fri Jan 19 10:48:35 2001 by faith@acm.org
  *
  * Copyright 2001 VA Linux Systems, Inc., Sunnyvale, California.
  * All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice (including the next
  * paragraph) shall be included in all copies or substantial portions of the
  * Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  * DEALINGS IN THE SOFTWARE.
  */

 #include <linux/fs.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/mount.h>
 #include <linux/slab.h>
 #include <drm/drmP.h>
 #include <drm/drm_core.h>

 unsigned int drm_debug = 0;	/* 1 to enable debug output */
 EXPORT_SYMBOL(drm_debug);

 unsigned int drm_rnodes = 0;	/* 1 to enable experimental render nodes API */
 EXPORT_SYMBOL(drm_rnodes);

 /* 1 to allow user space to request universal planes (experimental) */
 unsigned int drm_universal_planes = 0;
 EXPORT_SYMBOL(drm_universal_planes);

 unsigned int drm_vblank_offdelay = 5000;    /* Default to 5000 msecs. */
 EXPORT_SYMBOL(drm_vblank_offdelay);

 unsigned int drm_timestamp_precision = 20;  /* Default to 20 usecs. */
 EXPORT_SYMBOL(drm_timestamp_precision);

 /*
  * Default to use monotonic timestamps for wait-for-vblank and page-flip
  * complete events.
  */
 unsigned int drm_timestamp_monotonic = 1;

 MODULE_AUTHOR(CORE_AUTHOR);
 MODULE_DESCRIPTION(CORE_DESC);
 MODULE_LICENSE("GPL and additional rights");
 MODULE_PARM_DESC(debug, "Enable debug output");
 MODULE_PARM_DESC(rnodes, "Enable experimental render nodes API");
 MODULE_PARM_DESC(vblankoffdelay, "Delay until vblank irq auto-disable [msecs]");
 MODULE_PARM_DESC(timestamp_precision_usec, "Max. error on timestamps [usecs]");
 MODULE_PARM_DESC(timestamp_monotonic, "Use monotonic timestamps");

 module_param_named(debug, drm_debug, int, 0600);
 module_param_named(rnodes, drm_rnodes, int, 0600);
 module_param_named(universal_planes, drm_universal_planes, int, 0600);
 module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600);
 module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600);
 module_param_named(timestamp_monotonic, drm_timestamp_monotonic, int, 0600);

 static DEFINE_SPINLOCK(drm_minor_lock);
 struct idr drm_minors_idr;

 struct class *drm_class;
 struct dentry *drm_debugfs_root;

 int drm_err(const char *func, const char *format, ...)
 {
 	struct va_format vaf;
 	va_list args;
 	int r;

 	va_start(args, format);

 	vaf.fmt = format;
 	vaf.va = &args;

 	r = printk(KERN_ERR "[" DRM_NAME ":%s] *ERROR* %pV", func, &vaf);

 	va_end(args);

 	return r;
 }
 EXPORT_SYMBOL(drm_err);

 void drm_ut_debug_printk(const char *function_name, const char *format, ...)
 {
 	struct va_format vaf;
 	va_list args;

 	va_start(args, format);
 	vaf.fmt = format;
 	vaf.va = &args;

 	printk(KERN_DEBUG "[" DRM_NAME ":%s] %pV", function_name, &vaf);

 	va_end(args);
 }
 EXPORT_SYMBOL(drm_ut_debug_printk);

 struct drm_master *drm_master_create(struct drm_minor *minor)
 {
 	struct drm_master *master;

 	master = kzalloc(sizeof(*master), GFP_KERNEL);
 	if (!master)
 		return NULL;

 	kref_init(&master->refcount);
 	spin_lock_init(&master->lock.spinlock);
 	init_waitqueue_head(&master->lock.lock_queue);
 	if (drm_ht_create(&master->magiclist, DRM_MAGIC_HASH_ORDER)) {
 		kfree(master);
 		return NULL;
 	}
 	INIT_LIST_HEAD(&master->magicfree);
 	master->minor = minor;

 	return master;
 }

 struct drm_master *drm_master_get(struct drm_master *master)
 {
 	kref_get(&master->refcount);
 	return master;
 }
 EXPORT_SYMBOL(drm_master_get);

 static void drm_master_destroy(struct kref *kref)
 {
 	struct drm_master *master = container_of(kref, struct drm_master, refcount);
 	struct drm_magic_entry *pt, *next;
 	struct drm_device *dev = master->minor->dev;
 	struct drm_map_list *r_list, *list_temp;

 	mutex_lock(&dev->struct_mutex);
 	if (dev->driver->master_destroy)
 		dev->driver->master_destroy(dev, master);

 	list_for_each_entry_safe(r_list, list_temp, &dev->maplist, head) {
 		if (r_list->master == master) {
 			drm_rmmap_locked(dev, r_list->map);
 			r_list = NULL;
 		}
 	}

 	if (master->unique) {
 		kfree(master->unique);
 		master->unique = NULL;
 		master->unique_len = 0;
 	}

 	list_for_each_entry_safe(pt, next, &master->magicfree, head) {
 		list_del(&pt->head);
 		drm_ht_remove_item(&master->magiclist, &pt->hash_item);
 		kfree(pt);
 	}

 	drm_ht_remove(&master->magiclist);

 	mutex_unlock(&dev->struct_mutex);
 	kfree(master);
 }

 void drm_master_put(struct drm_master **master)
 {
 	kref_put(&(*master)->refcount, drm_master_destroy);
 	*master = NULL;
 }
 EXPORT_SYMBOL(drm_master_put);

 int drm_setmaster_ioctl(struct drm_device *dev, void *data,
 			struct drm_file *file_priv)
 {
 	int ret = 0;

 	mutex_lock(&dev->master_mutex);
 	if (file_priv->is_master)
 		goto out_unlock;

 	if (file_priv->minor->master) {
 		ret = -EINVAL;
 		goto out_unlock;
 	}

 	if (!file_priv->master) {
 		ret = -EINVAL;
 		goto out_unlock;
 	}

 	file_priv->minor->master = drm_master_get(file_priv->master);
 	file_priv->is_master = 1;
 	if (dev->driver->master_set) {
 		ret = dev->driver->master_set(dev, file_priv, false);
 		if (unlikely(ret != 0)) {
 			file_priv->is_master = 0;
 			drm_master_put(&file_priv->minor->master);
 		}
 	}

 out_unlock:
 	mutex_unlock(&dev->master_mutex);
 	return ret;
 }

 int drm_dropmaster_ioctl(struct drm_device *dev, void *data,
 			 struct drm_file *file_priv)
 {
 	int ret = -EINVAL;

 	mutex_lock(&dev->master_mutex);
 	if (!file_priv->is_master)
 		goto out_unlock;

 	if (!file_priv->minor->master)
 		goto out_unlock;

 	ret = 0;
 	if (dev->driver->master_drop)
 		dev->driver->master_drop(dev, file_priv, false);
 	drm_master_put(&file_priv->minor->master);
 	file_priv->is_master = 0;

 out_unlock:
 	mutex_unlock(&dev->master_mutex);
 	return ret;
 }

 /*
  * DRM Minors
  * A DRM device can provide several char-dev interfaces on the DRM-Major. Each
  * of them is represented by a drm_minor object. Depending on the capabilities
  * of the device-driver, different interfaces are registered.
  *
  * Minors can be accessed via dev->$minor_name. This pointer is either
  * NULL or a valid drm_minor pointer and stays valid as long as the device is
  * valid. This means, DRM minors have the same life-time as the underlying
  * device. However, this doesn't mean that the minor is active. Minors are
  * registered and unregistered dynamically according to device-state.
  */

 static struct drm_minor **drm_minor_get_slot(struct drm_device *dev,
 					     unsigned int type)
 {
 	switch (type) {
 	case DRM_MINOR_LEGACY:
 		return &dev->primary;
 	case DRM_MINOR_RENDER:
 		return &dev->render;
 	case DRM_MINOR_CONTROL:
 		return &dev->control;
 	default:
 		return NULL;
 	}
 }

 static int drm_minor_alloc(struct drm_device *dev, unsigned int type)
 {
 	struct drm_minor *minor;

 	minor = kzalloc(sizeof(*minor), GFP_KERNEL);
 	if (!minor)
 		return -ENOMEM;

 	minor->type = type;
 	minor->dev = dev;

 	*drm_minor_get_slot(dev, type) = minor;
 	return 0;
 }

 static void drm_minor_free(struct drm_device *dev, unsigned int type)
 {
 	struct drm_minor **slot;

 	slot = drm_minor_get_slot(dev, type);
 	if (*slot) {
 		drm_mode_group_destroy(&(*slot)->mode_group);
 		kfree(*slot);
 		*slot = NULL;
 	}
 }

 static int drm_minor_register(struct drm_device *dev, unsigned int type)
 {
 	struct drm_minor *new_minor;
 	unsigned long flags;
 	int ret;
 	int minor_id;

 	DRM_DEBUG("\n");

 	new_minor = *drm_minor_get_slot(dev, type);
 	if (!new_minor)
 		return 0;

 	idr_preload(GFP_KERNEL);
 	spin_lock_irqsave(&drm_minor_lock, flags);
 	minor_id = idr_alloc(&drm_minors_idr,
 			     NULL,
 			     64 * type,
 			     64 * (type + 1),
 			     GFP_NOWAIT);
 	spin_unlock_irqrestore(&drm_minor_lock, flags);
 	idr_preload_end();

 	if (minor_id < 0)
 		return minor_id;

 	new_minor->index = minor_id;

 	ret = drm_debugfs_init(new_minor, minor_id, drm_debugfs_root);
 	if (ret) {
 		DRM_ERROR("DRM: Failed to initialize /sys/kernel/debug/dri.\n");
 		goto err_id;
 	}

 	ret = drm_sysfs_device_add(new_minor);
 	if (ret) {
 		DRM_ERROR("DRM: Error sysfs_device_add.\n");
 		goto err_debugfs;
 	}

 	/* replace NULL with @minor so lookups will succeed from now on */
 	spin_lock_irqsave(&drm_minor_lock, flags);
 	idr_replace(&drm_minors_idr, new_minor, new_minor->index);
 	spin_unlock_irqrestore(&drm_minor_lock, flags);

 	DRM_DEBUG("new minor assigned %d\n", minor_id);
 	return 0;

 err_debugfs:
 	drm_debugfs_cleanup(new_minor);
 err_id:
 	spin_lock_irqsave(&drm_minor_lock, flags);
 	idr_remove(&drm_minors_idr, minor_id);
 	spin_unlock_irqrestore(&drm_minor_lock, flags);
 	new_minor->index = 0;
 	return ret;
 }

 static void drm_minor_unregister(struct drm_device *dev, unsigned int type)
 {
 	struct drm_minor *minor;
 	unsigned long flags;

 	minor = *drm_minor_get_slot(dev, type);
 	if (!minor || !minor->kdev)
 		return;

 	spin_lock_irqsave(&drm_minor_lock, flags);
 	idr_remove(&drm_minors_idr, minor->index);
 	spin_unlock_irqrestore(&drm_minor_lock, flags);
 	minor->index = 0;

 	drm_debugfs_cleanup(minor);
 	drm_sysfs_device_remove(minor);
 }

 /**
  * drm_minor_acquire - Acquire a DRM minor
  * @minor_id: Minor ID of the DRM-minor
  *
  * Looks up the given minor-ID and returns the respective DRM-minor object. The
  * refence-count of the underlying device is increased so you must release this
  * object with drm_minor_release().
  *
  * As long as you hold this minor, it is guaranteed that the object and the
  * minor->dev pointer will stay valid! However, the device may get unplugged and
  * unregistered while you hold the minor.
  *
  * Returns:
  * Pointer to minor-object with increased device-refcount, or PTR_ERR on
  * failure.
  */
 struct drm_minor *drm_minor_acquire(unsigned int minor_id)
 {
 	struct drm_minor *minor;
 	unsigned long flags;

 	spin_lock_irqsave(&drm_minor_lock, flags);
 	minor = idr_find(&drm_minors_idr, minor_id);
 	if (minor)
 		drm_dev_ref(minor->dev);
 	spin_unlock_irqrestore(&drm_minor_lock, flags);

 	if (!minor) {
 		return ERR_PTR(-ENODEV);
 	} else if (drm_device_is_unplugged(minor->dev)) {
 		drm_dev_unref(minor->dev);
 		return ERR_PTR(-ENODEV);
 	}

 	return minor;
 }

 /**
  * drm_minor_release - Release DRM minor
  * @minor: Pointer to DRM minor object
  *
  * Release a minor that was previously acquired via drm_minor_acquire().
  */
 void drm_minor_release(struct drm_minor *minor)
 {
 	drm_dev_unref(minor->dev);
 }

 /**
  * Called via drm_exit() at module unload time or when pci device is
  * unplugged.
  *
  * Cleans up all DRM device, calling drm_lastclose().
  *
  */
 void drm_put_dev(struct drm_device *dev)
 {
 	DRM_DEBUG("\n");

 	if (!dev) {
 		DRM_ERROR("cleanup called no dev\n");
 		return;
 	}

 	drm_dev_unregister(dev);
 	drm_dev_unref(dev);
 }
 EXPORT_SYMBOL(drm_put_dev);

 void drm_unplug_dev(struct drm_device *dev)
 {
 	/* for a USB device */
 	drm_minor_unregister(dev, DRM_MINOR_LEGACY);
 	drm_minor_unregister(dev, DRM_MINOR_RENDER);
 	drm_minor_unregister(dev, DRM_MINOR_CONTROL);

 	mutex_lock(&drm_global_mutex);

 	drm_device_set_unplugged(dev);

 	if (dev->open_count == 0) {
 		drm_put_dev(dev);
 	}
 	mutex_unlock(&drm_global_mutex);
 }
 EXPORT_SYMBOL(drm_unplug_dev);

 /*
  * DRM internal mount
  * We want to be able to allocate our own "struct address_space" to control
  * memory-mappings in VRAM (or stolen RAM, ...). However, core MM does not allow
  * stand-alone address_space objects, so we need an underlying inode. As there
  * is no way to allocate an independent inode easily, we need a fake internal
  * VFS mount-point.
  *
  * The drm_fs_inode_new() function allocates a new inode, drm_fs_inode_free()
  * frees it again. You are allowed to use iget() and iput() to get references to
  * the inode. But each drm_fs_inode_new() call must be paired with exactly one
  * drm_fs_inode_free() call (which does not have to be the last iput()).
  * We use drm_fs_inode_*() to manage our internal VFS mount-point and share it
  * between multiple inode-users. You could, technically, call
  * iget() + drm_fs_inode_free() directly after alloc and sometime later do an
  * iput(), but this way you'd end up with a new vfsmount for each inode.
  */

 static int drm_fs_cnt;
 static struct vfsmount *drm_fs_mnt;

 static const struct dentry_operations drm_fs_dops = {
 	.d_dname	= simple_dname,
 };

 static const struct super_operations drm_fs_sops = {
 	.statfs		= simple_statfs,
 };

 static struct dentry *drm_fs_mount(struct file_system_type *fs_type, int flags,
 				   const char *dev_name, void *data)
 {
 	return mount_pseudo(fs_type,
 			    "drm:",
 			    &drm_fs_sops,
 			    &drm_fs_dops,
 			    0x010203ff);
 }

 static struct file_system_type drm_fs_type = {
 	.name		= "drm",
 	.owner		= THIS_MODULE,
 	.mount		= drm_fs_mount,
 	.kill_sb	= kill_anon_super,
 };

 static struct inode *drm_fs_inode_new(void)
 {
 	struct inode *inode;
 	int r;

 	r = simple_pin_fs(&drm_fs_type, &drm_fs_mnt, &drm_fs_cnt);
 	if (r < 0) {
 		DRM_ERROR("Cannot mount pseudo fs: %d\n", r);
 		return ERR_PTR(r);
 	}

 	inode = alloc_anon_inode(drm_fs_mnt->mnt_sb);
 	if (IS_ERR(inode))
 		simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);

 	return inode;
 }

 static void drm_fs_inode_free(struct inode *inode)
 {
 	if (inode) {
 		iput(inode);
 		simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);
 	}
 }

 /**
  * drm_dev_alloc - Allocate new drm device
  * @driver: DRM driver to allocate device for
  * @parent: Parent device object
  *
  * Allocate and initialize a new DRM device. No device registration is done.
  * Call drm_dev_register() to advertice the device to user space and register it
  * with other core subsystems.
  *
  * The initial ref-count of the object is 1. Use drm_dev_ref() and
  * drm_dev_unref() to take and drop further ref-counts.
  *
  * RETURNS:
  * Pointer to new DRM device, or NULL if out of memory.
  */
 struct drm_device *drm_dev_alloc(struct drm_driver *driver,
 				 struct device *parent)
 {
 	struct drm_device *dev;
 	int ret;

 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 	if (!dev)
 		return NULL;

 	kref_init(&dev->ref);
 	dev->dev = parent;
 	dev->driver = driver;

 	INIT_LIST_HEAD(&dev->filelist);
 	INIT_LIST_HEAD(&dev->ctxlist);
 	INIT_LIST_HEAD(&dev->vmalist);
 	INIT_LIST_HEAD(&dev->maplist);
 	INIT_LIST_HEAD(&dev->vblank_event_list);

 	spin_lock_init(&dev->buf_lock);
 	spin_lock_init(&dev->event_lock);
 	mutex_init(&dev->struct_mutex);
 	mutex_init(&dev->ctxlist_mutex);
 	mutex_init(&dev->master_mutex);

 	dev->anon_inode = drm_fs_inode_new();
 	if (IS_ERR(dev->anon_inode)) {
 		ret = PTR_ERR(dev->anon_inode);
 		DRM_ERROR("Cannot allocate anonymous inode: %d\n", ret);
 		goto err_free;
 	}

 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
 		ret = drm_minor_alloc(dev, DRM_MINOR_CONTROL);
 		if (ret)
 			goto err_minors;
 	}

 	if (drm_core_check_feature(dev, DRIVER_RENDER) && drm_rnodes) {
 		ret = drm_minor_alloc(dev, DRM_MINOR_RENDER);
 		if (ret)
 			goto err_minors;
 	}

 	ret = drm_minor_alloc(dev, DRM_MINOR_LEGACY);
 	if (ret)
 		goto err_minors;

 	if (drm_ht_create(&dev->map_hash, 12))
 		goto err_minors;

 	ret = drm_ctxbitmap_init(dev);
 	if (ret) {
 		DRM_ERROR("Cannot allocate memory for context bitmap.\n");
 		goto err_ht;
 	}

 	if (driver->driver_features & DRIVER_GEM) {
 		ret = drm_gem_init(dev);
 		if (ret) {
 			DRM_ERROR("Cannot initialize graphics execution manager (GEM)\n");
 			goto err_ctxbitmap;
 		}
 	}

 	return dev;

 err_ctxbitmap:
 	drm_ctxbitmap_cleanup(dev);
 err_ht:
 	drm_ht_remove(&dev->map_hash);
 err_minors:
 	drm_minor_free(dev, DRM_MINOR_LEGACY);
 	drm_minor_free(dev, DRM_MINOR_RENDER);
 	drm_minor_free(dev, DRM_MINOR_CONTROL);
 	drm_fs_inode_free(dev->anon_inode);
 err_free:
 	mutex_destroy(&dev->master_mutex);
 	kfree(dev);
 	return NULL;
 }
 EXPORT_SYMBOL(drm_dev_alloc);

 static void drm_dev_release(struct kref *ref)
 {
 	struct drm_device *dev = container_of(ref, struct drm_device, ref);

 	if (dev->driver->driver_features & DRIVER_GEM)
 		drm_gem_destroy(dev);

 	drm_ctxbitmap_cleanup(dev);
 	drm_ht_remove(&dev->map_hash);
 	drm_fs_inode_free(dev->anon_inode);

 	drm_minor_free(dev, DRM_MINOR_LEGACY);
 	drm_minor_free(dev, DRM_MINOR_RENDER);
 	drm_minor_free(dev, DRM_MINOR_CONTROL);

 	mutex_destroy(&dev->master_mutex);
 	kfree(dev);
 }

 /**
  * drm_dev_ref - Take reference of a DRM device
  * @dev: device to take reference of or NULL
  *
  * This increases the ref-count of @dev by one. You *must* already own a
  * reference when calling this. Use drm_dev_unref() to drop this reference
  * again.
  *
  * This function never fails. However, this function does not provide *any*
  * guarantee whether the device is alive or running. It only provides a
  * reference to the object and the memory associated with it.
  */
 void drm_dev_ref(struct drm_device *dev)
 {
 	if (dev)
 		kref_get(&dev->ref);
 }
 EXPORT_SYMBOL(drm_dev_ref);

 /**
  * drm_dev_unref - Drop reference of a DRM device
  * @dev: device to drop reference of or NULL
  *
  * This decreases the ref-count of @dev by one. The device is destroyed if the
  * ref-count drops to zero.
  */
 void drm_dev_unref(struct drm_device *dev)
 {
 	if (dev)
 		kref_put(&dev->ref, drm_dev_release);
 }
 EXPORT_SYMBOL(drm_dev_unref);

 /**
  * drm_dev_register - Register DRM device
  * @dev: Device to register
  *
  * Register the DRM device @dev with the system, advertise device to user-space
  * and start normal device operation. @dev must be allocated via drm_dev_alloc()
  * previously.
  *
  * Never call this twice on any device!
  *
  * RETURNS:
  * 0 on success, negative error code on failure.
  */
 int drm_dev_register(struct drm_device *dev, unsigned long flags)
 {
 	int ret;

 	mutex_lock(&drm_global_mutex);

 	ret = drm_minor_register(dev, DRM_MINOR_CONTROL);
 	if (ret)
 		goto err_minors;

 	ret = drm_minor_register(dev, DRM_MINOR_RENDER);
 	if (ret)
 		goto err_minors;

 	ret = drm_minor_register(dev, DRM_MINOR_LEGACY);
 	if (ret)
 		goto err_minors;

 	if (dev->driver->load) {
 		ret = dev->driver->load(dev, flags);
 		if (ret)
 			goto err_minors;
 	}

 	/* setup grouping for legacy outputs */
 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
 		ret = drm_mode_group_init_legacy_group(dev,
 				&dev->primary->mode_group);
 		if (ret)
 			goto err_unload;
 	}

 	ret = 0;
 	goto out_unlock;

 err_unload:
 	if (dev->driver->unload)
 		dev->driver->unload(dev);
 err_minors:
 	drm_minor_unregister(dev, DRM_MINOR_LEGACY);
 	drm_minor_unregister(dev, DRM_MINOR_RENDER);
 	drm_minor_unregister(dev, DRM_MINOR_CONTROL);
 out_unlock:
 	mutex_unlock(&drm_global_mutex);
 	return ret;
 }
 EXPORT_SYMBOL(drm_dev_register);

 /**
  * drm_dev_unregister - Unregister DRM device
  * @dev: Device to unregister
  *
  * Unregister the DRM device from the system. This does the reverse of
  * drm_dev_register() but does not deallocate the device. The caller must call
  * drm_dev_unref() to drop their final reference.
  */
 void drm_dev_unregister(struct drm_device *dev)
 {
 	struct drm_map_list *r_list, *list_temp;

 	drm_lastclose(dev);

 	if (dev->driver->unload)
 		dev->driver->unload(dev);

 	if (dev->agp)
 		drm_pci_agp_destroy(dev);

 	drm_vblank_cleanup(dev);

 	list_for_each_entry_safe(r_list, list_temp, &dev->maplist, head)
 		drm_rmmap(dev, r_list->map);

 	drm_minor_unregister(dev, DRM_MINOR_LEGACY);
 	drm_minor_unregister(dev, DRM_MINOR_RENDER);
 	drm_minor_unregister(dev, DRM_MINOR_CONTROL);
 }
 EXPORT_SYMBOL(drm_dev_unregister);
	/**
	* \file drm_stub.h
	* Stub support
	*
	* \author Rickard E. (Rik) Faith <faith@valinux.com>
	*/

	/*
	* Created: Fri Jan 19 10:48:35 2001 by faith@acm.org
	*
	* Copyright 2001 VA Linux Systems, Inc., Sunnyvale, California.
	* All Rights Reserved.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice (including the next
	* paragraph) shall be included in all copies or substantial portions of the
	* Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
	* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
	* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
	* DEALINGS IN THE SOFTWARE.
	*/

	#include <linux/fs.h>
	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/mount.h>
	#include <linux/slab.h>
	#include <drm/drmP.h>
	#include <drm/drm_core.h>

	unsigned int drm_debug = 0; /* 1 to enable debug output */
	EXPORT_SYMBOL(drm_debug);

	unsigned int drm_rnodes = 0; /* 1 to enable experimental render nodes API */
	EXPORT_SYMBOL(drm_rnodes);

	/* 1 to allow user space to request universal planes (experimental) */
	unsigned int drm_universal_planes = 0;
	EXPORT_SYMBOL(drm_universal_planes);

	unsigned int drm_vblank_offdelay = 5000; /* Default to 5000 msecs. */
	EXPORT_SYMBOL(drm_vblank_offdelay);

	unsigned int drm_timestamp_precision = 20; /* Default to 20 usecs. */
	EXPORT_SYMBOL(drm_timestamp_precision);

	/*
	* Default to use monotonic timestamps for wait-for-vblank and page-flip
	* complete events.
	*/
	unsigned int drm_timestamp_monotonic = 1;

	MODULE_AUTHOR(CORE_AUTHOR);
	MODULE_DESCRIPTION(CORE_DESC);
	MODULE_LICENSE("GPL and additional rights");
	MODULE_PARM_DESC(debug, "Enable debug output");
	MODULE_PARM_DESC(rnodes, "Enable experimental render nodes API");
	MODULE_PARM_DESC(vblankoffdelay, "Delay until vblank irq auto-disable [msecs]");
	MODULE_PARM_DESC(timestamp_precision_usec, "Max. error on timestamps [usecs]");
	MODULE_PARM_DESC(timestamp_monotonic, "Use monotonic timestamps");

	module_param_named(debug, drm_debug, int, 0600);
	module_param_named(rnodes, drm_rnodes, int, 0600);
	module_param_named(universal_planes, drm_universal_planes, int, 0600);
	module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600);
	module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600);
	module_param_named(timestamp_monotonic, drm_timestamp_monotonic, int, 0600);

	static DEFINE_SPINLOCK(drm_minor_lock);
	struct idr drm_minors_idr;

	struct class *drm_class;
	struct dentry *drm_debugfs_root;

	int drm_err(const char func, const char format, ...)
	{
	struct va_format vaf;
	va_list args;
	int r;

	va_start(args, format);

	vaf.fmt = format;
	vaf.va = &args;

	r = printk(KERN_ERR "[" DRM_NAME ":%s] ERROR %pV", func, &vaf);

	va_end(args);

	return r;
	}
	EXPORT_SYMBOL(drm_err);

	void drm_ut_debug_printk(const char function_name, const char format, ...)
	{
	struct va_format vaf;
	va_list args;

	va_start(args, format);
	vaf.fmt = format;
	vaf.va = &args;

	printk(KERN_DEBUG "[" DRM_NAME ":%s] %pV", function_name, &vaf);

	va_end(args);
	}
	EXPORT_SYMBOL(drm_ut_debug_printk);

	struct drm_master drm_master_create(struct drm_minor minor)
	{
	struct drm_master *master;

	master = kzalloc(sizeof(*master), GFP_KERNEL);
	if (!master)
	return NULL;

	kref_init(&master->refcount);
	spin_lock_init(&master->lock.spinlock);
	init_waitqueue_head(&master->lock.lock_queue);
	if (drm_ht_create(&master->magiclist, DRM_MAGIC_HASH_ORDER)) {
	kfree(master);
	return NULL;
	}
	INIT_LIST_HEAD(&master->magicfree);
	master->minor = minor;

	return master;
	}

	struct drm_master drm_master_get(struct drm_master master)
	{
	kref_get(&master->refcount);
	return master;
	}
	EXPORT_SYMBOL(drm_master_get);

	static void drm_master_destroy(struct kref *kref)
	{
	struct drm_master *master = container_of(kref, struct drm_master, refcount);
	struct drm_magic_entry pt, next;
	struct drm_device *dev = master->minor->dev;
	struct drm_map_list r_list, list_temp;

	mutex_lock(&dev->struct_mutex);
	if (dev->driver->master_destroy)
	dev->driver->master_destroy(dev, master);

	list_for_each_entry_safe(r_list, list_temp, &dev->maplist, head) {
	if (r_list->master == master) {
	drm_rmmap_locked(dev, r_list->map);
	r_list = NULL;
	}
	}

	if (master->unique) {
	kfree(master->unique);
	master->unique = NULL;
	master->unique_len = 0;
	}

	list_for_each_entry_safe(pt, next, &master->magicfree, head) {
	list_del(&pt->head);
	drm_ht_remove_item(&master->magiclist, &pt->hash_item);
	kfree(pt);
	}

	drm_ht_remove(&master->magiclist);

	mutex_unlock(&dev->struct_mutex);
	kfree(master);
	}

	void drm_master_put(struct drm_master **master)
	{
	kref_put(&(*master)->refcount, drm_master_destroy);
	*master = NULL;
	}
	EXPORT_SYMBOL(drm_master_put);

	int drm_setmaster_ioctl(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	int ret = 0;

	mutex_lock(&dev->master_mutex);
	if (file_priv->is_master)
	goto out_unlock;

	if (file_priv->minor->master) {
	ret = -EINVAL;
	goto out_unlock;
	}

	if (!file_priv->master) {
	ret = -EINVAL;
	goto out_unlock;
	}

	file_priv->minor->master = drm_master_get(file_priv->master);
	file_priv->is_master = 1;
	if (dev->driver->master_set) {
	ret = dev->driver->master_set(dev, file_priv, false);
	if (unlikely(ret != 0)) {
	file_priv->is_master = 0;
	drm_master_put(&file_priv->minor->master);
	}
	}

	out_unlock:
	mutex_unlock(&dev->master_mutex);
	return ret;
	}

	int drm_dropmaster_ioctl(struct drm_device dev, void data,
	struct drm_file *file_priv)
	{
	int ret = -EINVAL;

	mutex_lock(&dev->master_mutex);
	if (!file_priv->is_master)
	goto out_unlock;

	if (!file_priv->minor->master)
	goto out_unlock;

	ret = 0;
	if (dev->driver->master_drop)
	dev->driver->master_drop(dev, file_priv, false);
	drm_master_put(&file_priv->minor->master);
	file_priv->is_master = 0;

	out_unlock:
	mutex_unlock(&dev->master_mutex);
	return ret;
	}

	/*
	* DRM Minors
	* A DRM device can provide several char-dev interfaces on the DRM-Major. Each
	* of them is represented by a drm_minor object. Depending on the capabilities
	* of the device-driver, different interfaces are registered.
	*
	* Minors can be accessed via dev->$minor_name. This pointer is either
	* NULL or a valid drm_minor pointer and stays valid as long as the device is
	* valid. This means, DRM minors have the same life-time as the underlying
	* device. However, this doesn't mean that the minor is active. Minors are
	* registered and unregistered dynamically according to device-state.
	*/

	static struct drm_minor *drm_minor_get_slot(struct drm_device dev,
	unsigned int type)
	{
	switch (type) {
	case DRM_MINOR_LEGACY:
	return &dev->primary;
	case DRM_MINOR_RENDER:
	return &dev->render;
	case DRM_MINOR_CONTROL:
	return &dev->control;
	default:
	return NULL;
	}
	}

	static int drm_minor_alloc(struct drm_device *dev, unsigned int type)
	{
	struct drm_minor *minor;

	minor = kzalloc(sizeof(*minor), GFP_KERNEL);
	if (!minor)
	return -ENOMEM;

	minor->type = type;
	minor->dev = dev;

	*drm_minor_get_slot(dev, type) = minor;
	return 0;
	}

	static void drm_minor_free(struct drm_device *dev, unsigned int type)
	{
	struct drm_minor **slot;

	slot = drm_minor_get_slot(dev, type);
	if (*slot) {
	drm_mode_group_destroy(&(*slot)->mode_group);
	kfree(*slot);
	*slot = NULL;
	}
	}

	static int drm_minor_register(struct drm_device *dev, unsigned int type)
	{
	struct drm_minor *new_minor;
	unsigned long flags;
	int ret;
	int minor_id;

	DRM_DEBUG("\n");

	new_minor = *drm_minor_get_slot(dev, type);
	if (!new_minor)
	return 0;

	idr_preload(GFP_KERNEL);
	spin_lock_irqsave(&drm_minor_lock, flags);
	minor_id = idr_alloc(&drm_minors_idr,
	NULL,
	64 * type,
	64 * (type + 1),
	GFP_NOWAIT);
	spin_unlock_irqrestore(&drm_minor_lock, flags);
	idr_preload_end();

	if (minor_id < 0)
	return minor_id;

	new_minor->index = minor_id;

	ret = drm_debugfs_init(new_minor, minor_id, drm_debugfs_root);
	if (ret) {
	DRM_ERROR("DRM: Failed to initialize /sys/kernel/debug/dri.\n");
	goto err_id;
	}

	ret = drm_sysfs_device_add(new_minor);
	if (ret) {
	DRM_ERROR("DRM: Error sysfs_device_add.\n");
	goto err_debugfs;
	}

	/* replace NULL with @minor so lookups will succeed from now on */
	spin_lock_irqsave(&drm_minor_lock, flags);
	idr_replace(&drm_minors_idr, new_minor, new_minor->index);
	spin_unlock_irqrestore(&drm_minor_lock, flags);

	DRM_DEBUG("new minor assigned %d\n", minor_id);
	return 0;

	err_debugfs:
	drm_debugfs_cleanup(new_minor);
	err_id:
	spin_lock_irqsave(&drm_minor_lock, flags);
	idr_remove(&drm_minors_idr, minor_id);
	spin_unlock_irqrestore(&drm_minor_lock, flags);
	new_minor->index = 0;
	return ret;
	}

	static void drm_minor_unregister(struct drm_device *dev, unsigned int type)
	{
	struct drm_minor *minor;
	unsigned long flags;

	minor = *drm_minor_get_slot(dev, type);
	if (!minor \|\| !minor->kdev)
	return;

	spin_lock_irqsave(&drm_minor_lock, flags);
	idr_remove(&drm_minors_idr, minor->index);
	spin_unlock_irqrestore(&drm_minor_lock, flags);
	minor->index = 0;

	drm_debugfs_cleanup(minor);
	drm_sysfs_device_remove(minor);
	}

	/**
	* drm_minor_acquire - Acquire a DRM minor
	* @minor_id: Minor ID of the DRM-minor
	*
	* Looks up the given minor-ID and returns the respective DRM-minor object. The
	* refence-count of the underlying device is increased so you must release this
	* object with drm_minor_release().
	*
	* As long as you hold this minor, it is guaranteed that the object and the
	* minor->dev pointer will stay valid! However, the device may get unplugged and
	* unregistered while you hold the minor.
	*
	* Returns:
	* Pointer to minor-object with increased device-refcount, or PTR_ERR on
	* failure.
	*/
	struct drm_minor *drm_minor_acquire(unsigned int minor_id)
	{
	struct drm_minor *minor;
	unsigned long flags;

	spin_lock_irqsave(&drm_minor_lock, flags);
	minor = idr_find(&drm_minors_idr, minor_id);
	if (minor)
	drm_dev_ref(minor->dev);
	spin_unlock_irqrestore(&drm_minor_lock, flags);

	if (!minor) {
	return ERR_PTR(-ENODEV);
	} else if (drm_device_is_unplugged(minor->dev)) {
	drm_dev_unref(minor->dev);
	return ERR_PTR(-ENODEV);
	}

	return minor;
	}

	/**
	* drm_minor_release - Release DRM minor
	* @minor: Pointer to DRM minor object
	*
	* Release a minor that was previously acquired via drm_minor_acquire().
	*/
	void drm_minor_release(struct drm_minor *minor)
	{
	drm_dev_unref(minor->dev);
	}

	/**
	* Called via drm_exit() at module unload time or when pci device is
	* unplugged.
	*
	* Cleans up all DRM device, calling drm_lastclose().
	*
	*/
	void drm_put_dev(struct drm_device *dev)
	{
	DRM_DEBUG("\n");

	if (!dev) {
	DRM_ERROR("cleanup called no dev\n");
	return;
	}

	drm_dev_unregister(dev);
	drm_dev_unref(dev);
	}
	EXPORT_SYMBOL(drm_put_dev);

	void drm_unplug_dev(struct drm_device *dev)
	{
	/* for a USB device */
	drm_minor_unregister(dev, DRM_MINOR_LEGACY);
	drm_minor_unregister(dev, DRM_MINOR_RENDER);
	drm_minor_unregister(dev, DRM_MINOR_CONTROL);

	mutex_lock(&drm_global_mutex);

	drm_device_set_unplugged(dev);

	if (dev->open_count == 0) {
	drm_put_dev(dev);
	}
	mutex_unlock(&drm_global_mutex);
	}
	EXPORT_SYMBOL(drm_unplug_dev);

	/*
	* DRM internal mount
	* We want to be able to allocate our own "struct address_space" to control
	* memory-mappings in VRAM (or stolen RAM, ...). However, core MM does not allow
	* stand-alone address_space objects, so we need an underlying inode. As there
	* is no way to allocate an independent inode easily, we need a fake internal
	* VFS mount-point.
	*
	* The drm_fs_inode_new() function allocates a new inode, drm_fs_inode_free()
	* frees it again. You are allowed to use iget() and iput() to get references to
	* the inode. But each drm_fs_inode_new() call must be paired with exactly one
	* drm_fs_inode_free() call (which does not have to be the last iput()).
	* We use drm_fs_inode_*() to manage our internal VFS mount-point and share it
	* between multiple inode-users. You could, technically, call
	* iget() + drm_fs_inode_free() directly after alloc and sometime later do an
	* iput(), but this way you'd end up with a new vfsmount for each inode.
	*/

	static int drm_fs_cnt;
	static struct vfsmount *drm_fs_mnt;

	static const struct dentry_operations drm_fs_dops = {
	.d_dname = simple_dname,
	};

	static const struct super_operations drm_fs_sops = {
	.statfs = simple_statfs,
	};

	static struct dentry drm_fs_mount(struct file_system_type fs_type, int flags,
	const char dev_name, void data)
	{
	return mount_pseudo(fs_type,
	"drm:",
	&drm_fs_sops,
	&drm_fs_dops,
	0x010203ff);
	}

	static struct file_system_type drm_fs_type = {
	.name = "drm",
	.owner = THIS_MODULE,
	.mount = drm_fs_mount,
	.kill_sb = kill_anon_super,
	};

	static struct inode *drm_fs_inode_new(void)
	{
	struct inode *inode;
	int r;

	r = simple_pin_fs(&drm_fs_type, &drm_fs_mnt, &drm_fs_cnt);
	if (r < 0) {
	DRM_ERROR("Cannot mount pseudo fs: %d\n", r);
	return ERR_PTR(r);
	}

	inode = alloc_anon_inode(drm_fs_mnt->mnt_sb);
	if (IS_ERR(inode))
	simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);

	return inode;
	}

	static void drm_fs_inode_free(struct inode *inode)
	{
	if (inode) {
	iput(inode);
	simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);
	}
	}

	/**
	* drm_dev_alloc - Allocate new drm device
	* @driver: DRM driver to allocate device for
	* @parent: Parent device object
	*
	* Allocate and initialize a new DRM device. No device registration is done.
	* Call drm_dev_register() to advertice the device to user space and register it
	* with other core subsystems.
	*
	* The initial ref-count of the object is 1. Use drm_dev_ref() and
	* drm_dev_unref() to take and drop further ref-counts.
	*
	* RETURNS:
	* Pointer to new DRM device, or NULL if out of memory.
	*/
	struct drm_device drm_dev_alloc(struct drm_driver driver,
	struct device *parent)
	{
	struct drm_device *dev;
	int ret;

	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (!dev)
	return NULL;

	kref_init(&dev->ref);
	dev->dev = parent;
	dev->driver = driver;

	INIT_LIST_HEAD(&dev->filelist);
	INIT_LIST_HEAD(&dev->ctxlist);
	INIT_LIST_HEAD(&dev->vmalist);
	INIT_LIST_HEAD(&dev->maplist);
	INIT_LIST_HEAD(&dev->vblank_event_list);

	spin_lock_init(&dev->buf_lock);
	spin_lock_init(&dev->event_lock);
	mutex_init(&dev->struct_mutex);
	mutex_init(&dev->ctxlist_mutex);
	mutex_init(&dev->master_mutex);

	dev->anon_inode = drm_fs_inode_new();
	if (IS_ERR(dev->anon_inode)) {
	ret = PTR_ERR(dev->anon_inode);
	DRM_ERROR("Cannot allocate anonymous inode: %d\n", ret);
	goto err_free;
	}

	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
	ret = drm_minor_alloc(dev, DRM_MINOR_CONTROL);
	if (ret)
	goto err_minors;
	}

	if (drm_core_check_feature(dev, DRIVER_RENDER) && drm_rnodes) {
	ret = drm_minor_alloc(dev, DRM_MINOR_RENDER);
	if (ret)
	goto err_minors;
	}

	ret = drm_minor_alloc(dev, DRM_MINOR_LEGACY);
	if (ret)
	goto err_minors;

	if (drm_ht_create(&dev->map_hash, 12))
	goto err_minors;

	ret = drm_ctxbitmap_init(dev);
	if (ret) {
	DRM_ERROR("Cannot allocate memory for context bitmap.\n");
	goto err_ht;
	}

	if (driver->driver_features & DRIVER_GEM) {
	ret = drm_gem_init(dev);
	if (ret) {
	DRM_ERROR("Cannot initialize graphics execution manager (GEM)\n");
	goto err_ctxbitmap;
	}
	}

	return dev;

	err_ctxbitmap:
	drm_ctxbitmap_cleanup(dev);
	err_ht:
	drm_ht_remove(&dev->map_hash);
	err_minors:
	drm_minor_free(dev, DRM_MINOR_LEGACY);
	drm_minor_free(dev, DRM_MINOR_RENDER);
	drm_minor_free(dev, DRM_MINOR_CONTROL);
	drm_fs_inode_free(dev->anon_inode);
	err_free:
	mutex_destroy(&dev->master_mutex);
	kfree(dev);
	return NULL;
	}
	EXPORT_SYMBOL(drm_dev_alloc);

	static void drm_dev_release(struct kref *ref)
	{
	struct drm_device *dev = container_of(ref, struct drm_device, ref);

	if (dev->driver->driver_features & DRIVER_GEM)
	drm_gem_destroy(dev);

	drm_ctxbitmap_cleanup(dev);
	drm_ht_remove(&dev->map_hash);
	drm_fs_inode_free(dev->anon_inode);

	drm_minor_free(dev, DRM_MINOR_LEGACY);
	drm_minor_free(dev, DRM_MINOR_RENDER);
	drm_minor_free(dev, DRM_MINOR_CONTROL);

	mutex_destroy(&dev->master_mutex);
	kfree(dev);
	}

	/**
	* drm_dev_ref - Take reference of a DRM device
	* @dev: device to take reference of or NULL
	*
	* This increases the ref-count of @dev by one. You must already own a
	* reference when calling this. Use drm_dev_unref() to drop this reference
	* again.
	*
	* This function never fails. However, this function does not provide any
	* guarantee whether the device is alive or running. It only provides a
	* reference to the object and the memory associated with it.
	*/
	void drm_dev_ref(struct drm_device *dev)
	{
	if (dev)
	kref_get(&dev->ref);
	}
	EXPORT_SYMBOL(drm_dev_ref);

	/**
	* drm_dev_unref - Drop reference of a DRM device
	* @dev: device to drop reference of or NULL
	*
	* This decreases the ref-count of @dev by one. The device is destroyed if the
	* ref-count drops to zero.
	*/
	void drm_dev_unref(struct drm_device *dev)
	{
	if (dev)
	kref_put(&dev->ref, drm_dev_release);
	}
	EXPORT_SYMBOL(drm_dev_unref);

	/**
	* drm_dev_register - Register DRM device
	* @dev: Device to register
	*
	* Register the DRM device @dev with the system, advertise device to user-space
	* and start normal device operation. @dev must be allocated via drm_dev_alloc()
	* previously.
	*
	* Never call this twice on any device!
	*
	* RETURNS:
	* 0 on success, negative error code on failure.
	*/
	int drm_dev_register(struct drm_device *dev, unsigned long flags)
	{
	int ret;

	mutex_lock(&drm_global_mutex);

	ret = drm_minor_register(dev, DRM_MINOR_CONTROL);
	if (ret)
	goto err_minors;

	ret = drm_minor_register(dev, DRM_MINOR_RENDER);
	if (ret)
	goto err_minors;

	ret = drm_minor_register(dev, DRM_MINOR_LEGACY);
	if (ret)
	goto err_minors;

	if (dev->driver->load) {
	ret = dev->driver->load(dev, flags);
	if (ret)
	goto err_minors;
	}

	/* setup grouping for legacy outputs */
	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
	ret = drm_mode_group_init_legacy_group(dev,
	&dev->primary->mode_group);
	if (ret)
	goto err_unload;
	}

	ret = 0;
	goto out_unlock;

	err_unload:
	if (dev->driver->unload)
	dev->driver->unload(dev);
	err_minors:
	drm_minor_unregister(dev, DRM_MINOR_LEGACY);
	drm_minor_unregister(dev, DRM_MINOR_RENDER);
	drm_minor_unregister(dev, DRM_MINOR_CONTROL);
	out_unlock:
	mutex_unlock(&drm_global_mutex);
	return ret;
	}
	EXPORT_SYMBOL(drm_dev_register);

	/**
	* drm_dev_unregister - Unregister DRM device
	* @dev: Device to unregister
	*
	* Unregister the DRM device from the system. This does the reverse of
	* drm_dev_register() but does not deallocate the device. The caller must call
	* drm_dev_unref() to drop their final reference.
	*/
	void drm_dev_unregister(struct drm_device *dev)
	{
	struct drm_map_list r_list, list_temp;

	drm_lastclose(dev);

	if (dev->driver->unload)
	dev->driver->unload(dev);

	if (dev->agp)
	drm_pci_agp_destroy(dev);

	drm_vblank_cleanup(dev);

	list_for_each_entry_safe(r_list, list_temp, &dev->maplist, head)
	drm_rmmap(dev, r_list->map);

	drm_minor_unregister(dev, DRM_MINOR_LEGACY);
	drm_minor_unregister(dev, DRM_MINOR_RENDER);
	drm_minor_unregister(dev, DRM_MINOR_CONTROL);
	}
	EXPORT_SYMBOL(drm_dev_unregister);