/*
* Copyright (c) 2016 Intel Corporation
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that copyright
* notice and this permission notice appear in supporting documentation, and
* that the name of the copyright holders not be used in advertising or
* publicity pertaining to distribution of the software without specific,
* written prior permission. The copyright holders make no representations
* about the suitability of this software for any purpose. It is provided "as
* is" without express or implied warranty.
*
* THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
* OF THIS SOFTWARE.
*/
#include <linux/export.h>
#include <drm/drmP.h>
#include <drm/drm_auth.h>
#include <drm/drm_framebuffer.h>
#include "drm_crtc_internal.h"
/**
* DOC: overview
*
* Frame buffers are abstract memory objects that provide a source of pixels to
* scanout to a CRTC. Applications explicitly request the creation of frame
* buffers through the DRM_IOCTL_MODE_ADDFB(2) ioctls and receive an opaque
* handle that can be passed to the KMS CRTC control, plane configuration and
* page flip functions.
*
* Frame buffers rely on the underlying memory manager for allocating backing
* storage. When creating a frame buffer applications pass a memory handle
* (or a list of memory handles for multi-planar formats) through the
* struct &drm_mode_fb_cmd2 argument. For drivers using GEM as their userspace
* buffer management interface this would be a GEM handle. Drivers are however
* free to use their own backing storage object handles, e.g. vmwgfx directly
* exposes special TTM handles to userspace and so expects TTM handles in the
* create ioctl and not GEM handles.
*
* Framebuffers are tracked with struct &drm_framebuffer. They are published
* using drm_framebuffer_init() - after calling that function userspace can use
* and access the framebuffer object. The helper function
* drm_helper_mode_fill_fb_struct() can be used to pre-fill the required
* metadata fields.
*
* The lifetime of a drm framebuffer is controlled with a reference count,
* drivers can grab additional references with drm_framebuffer_reference() and
* drop them again with drm_framebuffer_unreference(). For driver-private
* framebuffers for which the last reference is never dropped (e.g. for the
* fbdev framebuffer when the struct struct &drm_framebuffer is embedded into
* the fbdev helper struct) drivers can manually clean up a framebuffer at
* module unload time with drm_framebuffer_unregister_private(). But doing this
* is not recommended, and it's better to have a normal free-standing struct
* &drm_framebuffer.
*/
int drm_framebuffer_check_src_coords(uint32_t src_x, uint32_t src_y,
uint32_t src_w, uint32_t src_h,
const struct drm_framebuffer *fb)
{
unsigned int fb_width, fb_height;
fb_width = fb->width << 16;
fb_height = fb->height << 16;
/* Make sure source coordinates are inside the fb. */
if (src_w > fb_width ||
src_x > fb_width - src_w ||
src_h > fb_height ||
src_y > fb_height - src_h) {
DRM_DEBUG_KMS("Invalid source coordinates "
"%u.%06ux%u.%06u+%u.%06u+%u.%06u\n",
src_w >> 16, ((src_w & 0xffff) * 15625) >> 10,
src_h >> 16, ((src_h & 0xffff) * 15625) >> 10,
src_x >> 16, ((src_x & 0xffff) * 15625) >> 10,
src_y >> 16, ((src_y & 0xffff) * 15625) >> 10);
return -ENOSPC;
}
return 0;
}
/**
* drm_mode_addfb - add an FB to the graphics configuration
* @dev: drm device for the ioctl
* @data: data pointer for the ioctl
* @file_priv: drm file for the ioctl call
*
* Add a new FB to the specified CRTC, given a user request. This is the
* original addfb ioctl which only supported RGB formats.
*
* Called by the user via ioctl.
*
* Returns:
* Zero on success, negative errno on failure.
*/
int drm_mode_addfb(struct drm_device *dev,
void *data, struct drm_file *file_priv)
{
struct drm_mode_fb_cmd *or = data;
struct drm_mode_fb_cmd2 r = {};
int ret;
/* convert to new format and call new ioctl */
r.fb_id = or->fb_id;
r.width = or->width;
r.height = or->height;
r.pitches[0] = or->pitch;
r.pixel_format = drm_mode_legacy_fb_format(or->bpp, or->depth);
r.handles[0] = or->handle;
ret = drm_mode_addfb2(dev, &r, file_priv);
if (ret)
return ret;
or->fb_id = r.fb_id;
return 0;
}
static int framebuffer_check(const struct drm_mode_fb_cmd2 *r)
{
const struct drm_format_info *info;
int i;
info = __drm_format_info(r->pixel_format & ~DRM_FORMAT_BIG_ENDIAN);
if (!info) {
struct drm_format_name_buf format_name;
DRM_DEBUG_KMS("bad framebuffer format %s\n",
drm_get_format_name(r->pixel_format,
&format_name));
return -EINVAL;
}
if (r->width == 0 || r->width % info->hsub) {
DRM_DEBUG_KMS("bad framebuffer width %u\n", r->width);
return -EINVAL;
}
if (r->height == 0 || r->height % info->vsub) {
DRM_DEBUG_KMS("bad framebuffer height %u\n", r->height);
return -EINVAL;
}
for (i = 0; i < info->num_planes; i++) {
unsigned int width = r->width / (i != 0 ? info->hsub : 1);
unsigned int height = r->height / (i != 0 ? info->vsub : 1);
unsigned int cpp = info->cpp[i];
if (!r->handles[i]) {
DRM_DEBUG_KMS("no buffer object handle for plane %d\n", i);
return -EINVAL;
}
if ((uint64_t) width * cpp > UINT_MAX)
return -ERANGE;
if ((uint64_t) height * r->pitches[i] + r->offsets[i] > UINT_MAX)
return -ERANGE;
if (r->pitches[i] < width * cpp) {
DRM_DEBUG_KMS("bad pitch %u for plane %d\n", r->pitches[i], i);
return -EINVAL;
}
if (r->modifier[i] && !(r->flags & DRM_MODE_FB_MODIFIERS)) {
DRM_DEBUG_KMS("bad fb modifier %llu for plane %d\n",
r->modifier[i], i);
return -EINVAL;
}
if (r->flags & DRM_MODE_FB_MODIFIERS &&
r->modifier[i] != r->modifier[0]) {
DRM_DEBUG_KMS("bad fb modifier %llu for plane %d\n",
r->modifier[i], i);
return -EINVAL;
}
/* modifier specific checks: */
switch (r->modifier[i]) {
case DRM_FORMAT_MOD_SAMSUNG_64_32_TILE:
/* NOTE: the pitch restriction may be lifted later if it turns
* out that no hw has this restriction:
*/
if (r->pixel_format != DRM_FORMAT_NV12 ||
width % 128 || height % 32 ||
r->pitches[i] % 128) {
DRM_DEBUG_KMS("bad modifier data for plane %d\n", i);
return -EINVAL;
}
break;
default:
break;
}
}
for (i = info->num_planes; i < 4; i++) {
if (r->modifier[i]) {
DRM_DEBUG_KMS("non-zero modifier for unused plane %d\n", i);
return -EINVAL;
}
/* Pre-FB_MODIFIERS userspace didn't clear the structs properly. */
if (!(r->flags & DRM_MODE_FB_MODIFIERS))
continue;
if (r->handles[i]) {
DRM_DEBUG_KMS("buffer object handle for unused plane %d\n", i);
return -EINVAL;
}
if (r->pitches[i]) {
DRM_DEBUG_KMS("non-zero pitch for unused plane %d\n", i);
return -EINVAL;
}
if (r->offsets[i]) {
DRM_DEBUG_KMS("non-zero offset for unused plane %d\n", i);
return -EINVAL;
}
}
return 0;
}
struct drm_framebuffer *
drm_internal_framebuffer_create(struct drm_device *dev,
const struct drm_mode_fb_cmd2 *r,
struct drm_file *file_priv)
{
struct drm_mode_config *config = &dev->mode_config;
struct drm_framebuffer *fb;
int ret;
if (r->flags & ~(DRM_MODE_FB_INTERLACED | DRM_MODE_FB_MODIFIERS)) {
DRM_DEBUG_KMS("bad framebuffer flags 0x%08x\n", r->flags);
return ERR_PTR(-EINVAL);
}
if ((config->min_width > r->width) || (r->width > config->max_width)) {
DRM_DEBUG_KMS("bad framebuffer width %d, should be >= %d && <= %d\n",
r->width, config->min_width, config->max_width);
return ERR_PTR(-EINVAL);
}
if ((config->min_height > r->height) || (r->height > config->max_height)) {
DRM_DEBUG_KMS("bad framebuffer height %d, should be >= %d && <= %d\n",
r->height, config->min_height, config->max_height);
return ERR_PTR(-EINVAL);
}
if (r->flags & DRM_MODE_FB_MODIFIERS &&
!dev->mode_config.allow_fb_modifiers) {
DRM_DEBUG_KMS("driver does not support fb modifiers\n");
return ERR_PTR(-EINVAL);
}
ret = framebuffer_check(r);
if (ret)
return ERR_PTR(ret);
fb = dev->mode_config.funcs->fb_create(dev, file_priv, r);
if (IS_ERR(fb)) {
DRM_DEBUG_KMS("could not create framebuffer\n");
return fb;
}
return fb;
}
/**
* drm_mode_addfb2 - add an FB to the graphics configuration
* @dev: drm device for the ioctl
* @data: data pointer for the ioctl
* @file_priv: drm file for the ioctl call
*
* Add a new FB to the specified CRTC, given a user request with format. This is
* the 2nd version of the addfb ioctl, which supports multi-planar framebuffers
* and uses fourcc codes as pixel format specifiers.
*
* Called by the user via ioctl.
*
* Returns:
* Zero on success, negative errno on failure.
*/
int drm_mode_addfb2(struct drm_device *dev,
void *data, struct drm_file *file_priv)
{
struct drm_mode_fb_cmd2 *r = data;
struct drm_framebuffer *fb;
if (!drm_core_check_feature(dev, DRIVER_MODESET))
return -EINVAL;
fb = drm_internal_framebuffer_create(dev, r, file_priv);
if (IS_ERR(fb))
return PTR_ERR(fb);
DRM_DEBUG_KMS("[FB:%d]\n", fb->base.id);
r->fb_id = fb->base.id;
/* Transfer ownership to the filp for reaping on close */
mutex_lock(&file_priv->fbs_lock);
list_add(&fb->filp_head, &file_priv->fbs);
mutex_unlock(&file_priv->fbs_lock);
return 0;
}
struct drm_mode_rmfb_work {
struct work_struct work;
struct list_head fbs;
};
static void drm_mode_rmfb_work_fn(struct work_struct *w)
{
struct drm_mode_rmfb_work *arg = container_of(w, typeof(*arg), work);
while (!list_empty(&arg->fbs)) {
struct drm_framebuffer *fb =
list_first_entry(&arg->fbs, typeof(*fb), filp_head);
list_del_init(&fb->filp_head);
drm_framebuffer_remove(fb);
}
}
/**
* drm_mode_rmfb - remove an FB from the configuration
* @dev: drm device for the ioctl
* @data: data pointer for the ioctl
* @file_priv: drm file for the ioctl call
*
* Remove the FB specified by the user.
*
* Called by the user via ioctl.
*
* Returns:
* Zero on success, negative errno on failure.
*/
int drm_mode_rmfb(struct drm_device *dev,
void *data, struct drm_file *file_priv)
{
struct drm_framebuffer *fb = NULL;
struct drm_framebuffer *fbl = NULL;
uint32_t *id = data;
int found = 0;
if (!drm_core_check_feature(dev, DRIVER_MODESET))
return -EINVAL;
fb = drm_framebuffer_lookup(dev, *id);
if (!fb)
return -ENOENT;
mutex_lock(&file_priv->fbs_lock);
list_for_each_entry(fbl, &file_priv->fbs, filp_head)
if (fb == fbl)
found = 1;
if (!found) {
mutex_unlock(&file_priv->fbs_lock);
goto fail_unref;
}
list_del_init(&fb->filp_head);
mutex_unlock(&file_priv->fbs_lock);
/* drop the reference we picked up in framebuffer lookup */
drm_framebuffer_unreference(fb);
/*
* we now own the reference that was stored in the fbs list
*
* drm_framebuffer_remove may fail with -EINTR on pending signals,
* so run this in a separate stack as there's no way to correctly
* handle this after the fb is already removed from the lookup table.
*/
if (drm_framebuffer_read_refcount(fb) > 1) {
struct drm_mode_rmfb_work arg;
INIT_WORK_ONSTACK(&arg.work, drm_mode_rmfb_work_fn);
INIT_LIST_HEAD(&arg.fbs);
list_add_tail(&fb->filp_head, &arg.fbs);
schedule_work(&arg.work);
flush_work(&arg.work);
destroy_work_on_stack(&arg.work);
} else
drm_framebuffer_unreference(fb);
return 0;
fail_unref:
drm_framebuffer_unreference(fb);
return -ENOENT;
}
/**
* drm_mode_getfb - get FB info
* @dev: drm device for the ioctl
* @data: data pointer for the ioctl
* @file_priv: drm file for the ioctl call
*
* Lookup the FB given its ID and return info about it.
*
* Called by the user via ioctl.
*
* Returns:
* Zero on success, negative errno on failure.
*/
int drm_mode_getfb(struct drm_device *dev,
void *data, struct drm_file *file_priv)
{
struct drm_mode_fb_cmd *r = data;
struct drm_framebuffer *fb;
int ret;
if (!drm_core_check_feature(dev, DRIVER_MODESET))
return -EINVAL;
fb = drm_framebuffer_lookup(dev, r->fb_id);
if (!fb)
return -ENOENT;
r->height = fb->height;
r->width = fb->width;
r->depth = fb->depth;
r->bpp = fb->bits_per_pixel;
r->pitch = fb->pitches[0];
if (fb->funcs->create_handle) {
if (drm_is_current_master(file_priv) || capable(CAP_SYS_ADMIN) ||
drm_is_control_client(file_priv)) {
ret = fb->funcs->create_handle(fb, file_priv,
&r->handle);
} else {
/* GET_FB() is an unprivileged ioctl so we must not
* return a buffer-handle to non-master processes! For
* backwards-compatibility reasons, we cannot make
* GET_FB() privileged, so just return an invalid handle
* for non-masters. */
r->handle = 0;
ret = 0;
}
} else {
ret = -ENODEV;
}
drm_framebuffer_unreference(fb);
return ret;
}
/**
* drm_mode_dirtyfb_ioctl - flush frontbuffer rendering on an FB
* @dev: drm device for the ioctl
* @data: data pointer for the ioctl
* @file_priv: drm file for the ioctl call
*
* Lookup the FB and flush out the damaged area supplied by userspace as a clip
* rectangle list. Generic userspace which does frontbuffer rendering must call
* this ioctl to flush out the changes on manual-update display outputs, e.g.
* usb display-link, mipi manual update panels or edp panel self refresh modes.
*
* Modesetting drivers which always update the frontbuffer do not need to
* implement the corresponding ->dirty framebuffer callback.
*
* Called by the user via ioctl.
*
* Returns:
* Zero on success, negative errno on failure.
*/
int drm_mode_dirtyfb_ioctl(struct drm_device *dev,
void *data, struct drm_file *file_priv)
{
struct drm_clip_rect __user *clips_ptr;
struct drm_clip_rect *clips = NULL;
struct drm_mode_fb_dirty_cmd *r = data;
struct drm_framebuffer *fb;
unsigned flags;
int num_clips;
int ret;
if (!drm_core_check_feature(dev, DRIVER_MODESET))
return -EINVAL;
fb = drm_framebuffer_lookup(dev, r->fb_id);
if (!fb)
return -ENOENT;
num_clips = r->num_clips;
clips_ptr = (struct drm_clip_rect __user *)(unsigned long)r->clips_ptr;
if (!num_clips != !clips_ptr) {
ret = -EINVAL;
goto out_err1;
}
flags = DRM_MODE_FB_DIRTY_FLAGS & r->flags;
/* If userspace annotates copy, clips must come in pairs */
if (flags & DRM_MODE_FB_DIRTY_ANNOTATE_COPY && (num_clips % 2)) {
ret = -EINVAL;
goto out_err1;
}
if (num_clips && clips_ptr) {
if (num_clips < 0 || num_clips > DRM_MODE_FB_DIRTY_MAX_CLIPS) {
ret = -EINVAL;
goto out_err1;
}
clips = kcalloc(num_clips, sizeof(*clips), GFP_KERNEL);
if (!clips) {
ret = -ENOMEM;
goto out_err1;
}
ret = copy_from_user(clips, clips_ptr,
num_clips * sizeof(*clips));
if (ret) {
ret = -EFAULT;
goto out_err2;
}
}
if (fb->funcs->dirty) {
ret = fb->funcs->dirty(fb, file_priv, flags, r->color,
clips, num_clips);
} else {
ret = -ENOSYS;
}
out_err2:
kfree(clips);
out_err1:
drm_framebuffer_unreference(fb);
return ret;
}
/**
* drm_fb_release - remove and free the FBs on this file
* @priv: drm file for the ioctl
*
* Destroy all the FBs associated with @filp.
*
* Called by the user via ioctl.
*
* Returns:
* Zero on success, negative errno on failure.
*/
void drm_fb_release(struct drm_file *priv)
{
struct drm_framebuffer *fb, *tfb;
struct drm_mode_rmfb_work arg;
INIT_LIST_HEAD(&arg.fbs);
/*
* When the file gets released that means no one else can access the fb
* list any more, so no need to grab fpriv->fbs_lock. And we need to
* avoid upsetting lockdep since the universal cursor code adds a
* framebuffer while holding mutex locks.
*
* Note that a real deadlock between fpriv->fbs_lock and the modeset
* locks is impossible here since no one else but this function can get
* at it any more.
*/
list_for_each_entry_safe(fb, tfb, &priv->fbs, filp_head) {
if (drm_framebuffer_read_refcount(fb) > 1) {
list_move_tail(&fb->filp_head, &arg.fbs);
} else {
list_del_init(&fb->filp_head);
/* This drops the fpriv->fbs reference. */
drm_framebuffer_unreference(fb);
}
}
if (!list_empty(&arg.fbs)) {
INIT_WORK_ONSTACK(&arg.work, drm_mode_rmfb_work_fn);
schedule_work(&arg.work);
flush_work(&arg.work);
destroy_work_on_stack(&arg.work);
}
}
void drm_framebuffer_free(struct kref *kref)
{
struct drm_framebuffer *fb =
container_of(kref, struct drm_framebuffer, base.refcount);
struct drm_device *dev = fb->dev;
/*
* The lookup idr holds a weak reference, which has not necessarily been
* removed at this point. Check for that.
*/
drm_mode_object_unregister(dev, &fb->base);
fb->funcs->destroy(fb);
}
/**
* drm_framebuffer_init - initialize a framebuffer
* @dev: DRM device
* @fb: framebuffer to be initialized
* @funcs: ... with these functions
*
* Allocates an ID for the framebuffer's parent mode object, sets its mode
* functions & device file and adds it to the master fd list.
*
* IMPORTANT:
* This functions publishes the fb and makes it available for concurrent access
* by other users. Which means by this point the fb _must_ be fully set up -
* since all the fb attributes are invariant over its lifetime, no further
* locking but only correct reference counting is required.
*
* Returns:
* Zero on success, error code on failure.
*/
int drm_framebuffer_init(struct drm_device *dev, struct drm_framebuffer *fb,
const struct drm_framebuffer_funcs *funcs)
{
int ret;
INIT_LIST_HEAD(&fb->filp_head);
fb->dev = dev;
fb->funcs = funcs;
ret = drm_mode_object_get_reg(dev, &fb->base, DRM_MODE_OBJECT_FB,
false, drm_framebuffer_free);
if (ret)
goto out;
mutex_lock(&dev->mode_config.fb_lock);
dev->mode_config.num_fb++;
list_add(&fb->head, &dev->mode_config.fb_list);
mutex_unlock(&dev->mode_config.fb_lock);
drm_mode_object_register(dev, &fb->base);
out:
return ret;
}
EXPORT_SYMBOL(drm_framebuffer_init);
/**
* drm_framebuffer_lookup - look up a drm framebuffer and grab a reference
* @dev: drm device
* @id: id of the fb object
*
* If successful, this grabs an additional reference to the framebuffer -
* callers need to make sure to eventually unreference the returned framebuffer
* again, using @drm_framebuffer_unreference.
*/
struct drm_framebuffer *drm_framebuffer_lookup(struct drm_device *dev,
uint32_t id)
{
struct drm_mode_object *obj;
struct drm_framebuffer *fb = NULL;
obj = __drm_mode_object_find(dev, id, DRM_MODE_OBJECT_FB);
if (obj)
fb = obj_to_fb(obj);
return fb;
}
EXPORT_SYMBOL(drm_framebuffer_lookup);
/**
* drm_framebuffer_unregister_private - unregister a private fb from the lookup idr
* @fb: fb to unregister
*
* Drivers need to call this when cleaning up driver-private framebuffers, e.g.
* those used for fbdev. Note that the caller must hold a reference of it's own,
* i.e. the object may not be destroyed through this call (since it'll lead to a
* locking inversion).
*
* NOTE: This function is deprecated. For driver-private framebuffers it is not
* recommended to embed a framebuffer struct info fbdev struct, instead, a
* framebuffer pointer is preferred and drm_framebuffer_unreference() should be
* called when the framebuffer is to be cleaned up.
*/
void drm_framebuffer_unregister_private(struct drm_framebuffer *fb)
{
struct drm_device *dev;
if (!fb)
return;
dev = fb->dev;
/* Mark fb as reaped and drop idr ref. */
drm_mode_object_unregister(dev, &fb->base);
}
EXPORT_SYMBOL(drm_framebuffer_unregister_private);
/**
* drm_framebuffer_cleanup - remove a framebuffer object
* @fb: framebuffer to remove
*
* Cleanup framebuffer. This function is intended to be used from the drivers
* ->destroy callback. It can also be used to clean up driver private
* framebuffers embedded into a larger structure.
*
* Note that this function does not remove the fb from active usuage - if it is
* still used anywhere, hilarity can ensue since userspace could call getfb on
* the id and get back -EINVAL. Obviously no concern at driver unload time.
*
* Also, the framebuffer will not be removed from the lookup idr - for
* user-created framebuffers this will happen in in the rmfb ioctl. For
* driver-private objects (e.g. for fbdev) drivers need to explicitly call
* drm_framebuffer_unregister_private.
*/
void drm_framebuffer_cleanup(struct drm_framebuffer *fb)
{
struct drm_device *dev = fb->dev;
mutex_lock(&dev->mode_config.fb_lock);
list_del(&fb->head);
dev->mode_config.num_fb--;
mutex_unlock(&dev->mode_config.fb_lock);
}
EXPORT_SYMBOL(drm_framebuffer_cleanup);
/**
* drm_framebuffer_remove - remove and unreference a framebuffer object
* @fb: framebuffer to remove
*
* Scans all the CRTCs and planes in @dev's mode_config. If they're
* using @fb, removes it, setting it to NULL. Then drops the reference to the
* passed-in framebuffer. Might take the modeset locks.
*
* Note that this function optimizes the cleanup away if the caller holds the
* last reference to the framebuffer. It is also guaranteed to not take the
* modeset locks in this case.
*/
void drm_framebuffer_remove(struct drm_framebuffer *fb)
{
struct drm_device *dev;
struct drm_crtc *crtc;
struct drm_plane *plane;
if (!fb)
return;
dev = fb->dev;
WARN_ON(!list_empty(&fb->filp_head));
/*
* drm ABI mandates that we remove any deleted framebuffers from active
* useage. But since most sane clients only remove framebuffers they no
* longer need, try to optimize this away.
*
* Since we're holding a reference ourselves, observing a refcount of 1
* means that we're the last holder and can skip it. Also, the refcount
* can never increase from 1 again, so we don't need any barriers or
* locks.
*
* Note that userspace could try to race with use and instate a new
* usage _after_ we've cleared all current ones. End result will be an
* in-use fb with fb-id == 0. Userspace is allowed to shoot its own foot
* in this manner.
*/
if (drm_framebuffer_read_refcount(fb) > 1) {
drm_modeset_lock_all(dev);
/* remove from any CRTC */
drm_for_each_crtc(crtc, dev) {
if (crtc->primary->fb == fb) {
/* should turn off the crtc */
if (drm_crtc_force_disable(crtc))
DRM_ERROR("failed to reset crtc %p when fb was deleted\n", crtc);
}
}
drm_for_each_plane(plane, dev) {
if (plane->fb == fb)
drm_plane_force_disable(plane);
}
drm_modeset_unlock_all(dev);
}
drm_framebuffer_unreference(fb);
}
EXPORT_SYMBOL(drm_framebuffer_remove);