diff options
Diffstat (limited to 'drivers/gpu/drm/drm_framebuffer.c')
| -rw-r--r-- | drivers/gpu/drm/drm_framebuffer.c | 792 |
1 files changed, 792 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c new file mode 100644 index 000000000000..cbf0c893f426 --- /dev/null +++ b/drivers/gpu/drm/drm_framebuffer.c @@ -0,0 +1,792 @@ +/* + * 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); |