linux/drivers/gpu/drm/drm_fb_cma_helper.c

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/*
* drm kms/fb cma (contiguous memory allocator) helper functions
*
* Copyright (C) 2012 Analog Device Inc.
* Author: Lars-Peter Clausen <lars@metafoo.de>
*
* Based on udl_fbdev.c
* Copyright (C) 2012 Red Hat
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <drm/drmP.h>
#include <drm/drm_crtc.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_fb_cma_helper.h>
#include <linux/dma-mapping.h>
#include <linux/module.h>
#define DEFAULT_FBDEFIO_DELAY_MS 50
struct drm_fb_cma {
struct drm_framebuffer fb;
struct drm_gem_cma_object *obj[4];
};
struct drm_fbdev_cma {
struct drm_fb_helper fb_helper;
struct drm_fb_cma *fb;
};
/**
* DOC: framebuffer cma helper functions
*
* Provides helper functions for creating a cma (contiguous memory allocator)
* backed framebuffer.
*
* drm_fb_cma_create() is used in the &drm_mode_config_funcs ->fb_create
* callback function to create a cma backed framebuffer.
*
* An fbdev framebuffer backed by cma is also available by calling
* drm_fbdev_cma_init(). drm_fbdev_cma_fini() tears it down.
* If the &drm_framebuffer_funcs ->dirty callback is set, fb_deferred_io
* will be set up automatically. dirty() is called by
* drm_fb_helper_deferred_io() in process context (struct delayed_work).
*
* Example fbdev deferred io code::
*
* static int driver_fbdev_fb_dirty(struct drm_framebuffer *fb,
* struct drm_file *file_priv,
* unsigned flags, unsigned color,
* struct drm_clip_rect *clips,
* unsigned num_clips)
* {
* struct drm_gem_cma_object *cma = drm_fb_cma_get_gem_obj(fb, 0);
* ... push changes ...
* return 0;
* }
*
* static struct drm_framebuffer_funcs driver_fbdev_fb_funcs = {
* .destroy = drm_fb_cma_destroy,
* .create_handle = drm_fb_cma_create_handle,
* .dirty = driver_fbdev_fb_dirty,
* };
*
* static int driver_fbdev_create(struct drm_fb_helper *helper,
* struct drm_fb_helper_surface_size *sizes)
* {
* return drm_fbdev_cma_create_with_funcs(helper, sizes,
* &driver_fbdev_fb_funcs);
* }
*
* static const struct drm_fb_helper_funcs driver_fb_helper_funcs = {
* .fb_probe = driver_fbdev_create,
* };
*
* Initialize:
* fbdev = drm_fbdev_cma_init_with_funcs(dev, 16,
* dev->mode_config.num_crtc,
* dev->mode_config.num_connector,
* &driver_fb_helper_funcs);
*
*/
static inline struct drm_fbdev_cma *to_fbdev_cma(struct drm_fb_helper *helper)
{
return container_of(helper, struct drm_fbdev_cma, fb_helper);
}
static inline struct drm_fb_cma *to_fb_cma(struct drm_framebuffer *fb)
{
return container_of(fb, struct drm_fb_cma, fb);
}
void drm_fb_cma_destroy(struct drm_framebuffer *fb)
{
struct drm_fb_cma *fb_cma = to_fb_cma(fb);
int i;
for (i = 0; i < 4; i++) {
if (fb_cma->obj[i])
drm_gem_object_unreference_unlocked(&fb_cma->obj[i]->base);
}
drm_framebuffer_cleanup(fb);
kfree(fb_cma);
}
EXPORT_SYMBOL(drm_fb_cma_destroy);
int drm_fb_cma_create_handle(struct drm_framebuffer *fb,
struct drm_file *file_priv, unsigned int *handle)
{
struct drm_fb_cma *fb_cma = to_fb_cma(fb);
return drm_gem_handle_create(file_priv,
&fb_cma->obj[0]->base, handle);
}
EXPORT_SYMBOL(drm_fb_cma_create_handle);
static struct drm_framebuffer_funcs drm_fb_cma_funcs = {
.destroy = drm_fb_cma_destroy,
.create_handle = drm_fb_cma_create_handle,
};
static struct drm_fb_cma *drm_fb_cma_alloc(struct drm_device *dev,
const struct drm_mode_fb_cmd2 *mode_cmd,
struct drm_gem_cma_object **obj,
unsigned int num_planes, const struct drm_framebuffer_funcs *funcs)
{
struct drm_fb_cma *fb_cma;
int ret;
int i;
fb_cma = kzalloc(sizeof(*fb_cma), GFP_KERNEL);
if (!fb_cma)
return ERR_PTR(-ENOMEM);
drm_helper_mode_fill_fb_struct(&fb_cma->fb, mode_cmd);
for (i = 0; i < num_planes; i++)
fb_cma->obj[i] = obj[i];
ret = drm_framebuffer_init(dev, &fb_cma->fb, funcs);
if (ret) {
dev_err(dev->dev, "Failed to initialize framebuffer: %d\n", ret);
kfree(fb_cma);
return ERR_PTR(ret);
}
return fb_cma;
}
/**
* drm_fb_cma_create_with_funcs() - helper function for the
* &drm_mode_config_funcs ->fb_create
* callback function
* @dev: DRM device
* @file_priv: drm file for the ioctl call
* @mode_cmd: metadata from the userspace fb creation request
* @funcs: vtable to be used for the new framebuffer object
*
* This can be used to set &drm_framebuffer_funcs for drivers that need the
* dirty() callback. Use drm_fb_cma_create() if you don't need to change
* &drm_framebuffer_funcs.
*/
struct drm_framebuffer *drm_fb_cma_create_with_funcs(struct drm_device *dev,
struct drm_file *file_priv, const struct drm_mode_fb_cmd2 *mode_cmd,
const struct drm_framebuffer_funcs *funcs)
{
struct drm_fb_cma *fb_cma;
struct drm_gem_cma_object *objs[4];
struct drm_gem_object *obj;
unsigned int hsub;
unsigned int vsub;
int ret;
int i;
hsub = drm_format_horz_chroma_subsampling(mode_cmd->pixel_format);
vsub = drm_format_vert_chroma_subsampling(mode_cmd->pixel_format);
for (i = 0; i < drm_format_num_planes(mode_cmd->pixel_format); i++) {
unsigned int width = mode_cmd->width / (i ? hsub : 1);
unsigned int height = mode_cmd->height / (i ? vsub : 1);
unsigned int min_size;
obj = drm_gem_object_lookup(file_priv, mode_cmd->handles[i]);
if (!obj) {
dev_err(dev->dev, "Failed to lookup GEM object\n");
ret = -ENXIO;
goto err_gem_object_unreference;
}
min_size = (height - 1) * mode_cmd->pitches[i]
+ width * drm_format_plane_cpp(mode_cmd->pixel_format, i)
+ mode_cmd->offsets[i];
if (obj->size < min_size) {
drm_gem_object_unreference_unlocked(obj);
ret = -EINVAL;
goto err_gem_object_unreference;
}
objs[i] = to_drm_gem_cma_obj(obj);
}
fb_cma = drm_fb_cma_alloc(dev, mode_cmd, objs, i, funcs);
if (IS_ERR(fb_cma)) {
ret = PTR_ERR(fb_cma);
goto err_gem_object_unreference;
}
return &fb_cma->fb;
err_gem_object_unreference:
for (i--; i >= 0; i--)
drm_gem_object_unreference_unlocked(&objs[i]->base);
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(drm_fb_cma_create_with_funcs);
/**
* drm_fb_cma_create() - &drm_mode_config_funcs ->fb_create callback function
* @dev: DRM device
* @file_priv: drm file for the ioctl call
* @mode_cmd: metadata from the userspace fb creation request
*
* If your hardware has special alignment or pitch requirements these should be
* checked before calling this function. Use drm_fb_cma_create_with_funcs() if
* you need to set &drm_framebuffer_funcs ->dirty.
*/
struct drm_framebuffer *drm_fb_cma_create(struct drm_device *dev,
struct drm_file *file_priv, const struct drm_mode_fb_cmd2 *mode_cmd)
{
return drm_fb_cma_create_with_funcs(dev, file_priv, mode_cmd,
&drm_fb_cma_funcs);
}
EXPORT_SYMBOL_GPL(drm_fb_cma_create);
/**
* drm_fb_cma_get_gem_obj() - Get CMA GEM object for framebuffer
* @fb: The framebuffer
* @plane: Which plane
*
* Return the CMA GEM object for given framebuffer.
*
* This function will usually be called from the CRTC callback functions.
*/
struct drm_gem_cma_object *drm_fb_cma_get_gem_obj(struct drm_framebuffer *fb,
unsigned int plane)
{
struct drm_fb_cma *fb_cma = to_fb_cma(fb);
if (plane >= 4)
return NULL;
return fb_cma->obj[plane];
}
EXPORT_SYMBOL_GPL(drm_fb_cma_get_gem_obj);
#ifdef CONFIG_DEBUG_FS
static void drm_fb_cma_describe(struct drm_framebuffer *fb, struct seq_file *m)
{
struct drm_fb_cma *fb_cma = to_fb_cma(fb);
int i, n = drm_format_num_planes(fb->pixel_format);
seq_printf(m, "fb: %dx%d@%4.4s\n", fb->width, fb->height,
(char *)&fb->pixel_format);
for (i = 0; i < n; i++) {
seq_printf(m, " %d: offset=%d pitch=%d, obj: ",
i, fb->offsets[i], fb->pitches[i]);
drm_gem_cma_describe(fb_cma->obj[i], m);
}
}
/**
* drm_fb_cma_debugfs_show() - Helper to list CMA framebuffer objects
* in debugfs.
* @m: output file
* @arg: private data for the callback
*/
int drm_fb_cma_debugfs_show(struct seq_file *m, void *arg)
{
struct drm_info_node *node = (struct drm_info_node *) m->private;
struct drm_device *dev = node->minor->dev;
struct drm_framebuffer *fb;
mutex_lock(&dev->mode_config.fb_lock);
drm_for_each_fb(fb, dev)
drm_fb_cma_describe(fb, m);
mutex_unlock(&dev->mode_config.fb_lock);
return 0;
}
EXPORT_SYMBOL_GPL(drm_fb_cma_debugfs_show);
#endif
static int drm_fb_cma_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
return dma_mmap_writecombine(info->device, vma, info->screen_base,
info->fix.smem_start, info->fix.smem_len);
}
static struct fb_ops drm_fbdev_cma_ops = {
.owner = THIS_MODULE,
.fb_fillrect = drm_fb_helper_sys_fillrect,
.fb_copyarea = drm_fb_helper_sys_copyarea,
.fb_imageblit = drm_fb_helper_sys_imageblit,
.fb_check_var = drm_fb_helper_check_var,
.fb_set_par = drm_fb_helper_set_par,
.fb_blank = drm_fb_helper_blank,
.fb_pan_display = drm_fb_helper_pan_display,
.fb_setcmap = drm_fb_helper_setcmap,
.fb_mmap = drm_fb_cma_mmap,
};
static int drm_fbdev_cma_deferred_io_mmap(struct fb_info *info,
struct vm_area_struct *vma)
{
fb_deferred_io_mmap(info, vma);
vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
return 0;
}
static int drm_fbdev_cma_defio_init(struct fb_info *fbi,
struct drm_gem_cma_object *cma_obj)
{
struct fb_deferred_io *fbdefio;
struct fb_ops *fbops;
/*
* Per device structures are needed because:
* fbops: fb_deferred_io_cleanup() clears fbops.fb_mmap
* fbdefio: individual delays
*/
fbdefio = kzalloc(sizeof(*fbdefio), GFP_KERNEL);
fbops = kzalloc(sizeof(*fbops), GFP_KERNEL);
if (!fbdefio || !fbops) {
kfree(fbdefio);
kfree(fbops);
return -ENOMEM;
}
/* can't be offset from vaddr since dirty() uses cma_obj */
fbi->screen_buffer = cma_obj->vaddr;
/* fb_deferred_io_fault() needs a physical address */
fbi->fix.smem_start = page_to_phys(virt_to_page(fbi->screen_buffer));
*fbops = *fbi->fbops;
fbi->fbops = fbops;
fbdefio->delay = msecs_to_jiffies(DEFAULT_FBDEFIO_DELAY_MS);
fbdefio->deferred_io = drm_fb_helper_deferred_io;
fbi->fbdefio = fbdefio;
fb_deferred_io_init(fbi);
fbi->fbops->fb_mmap = drm_fbdev_cma_deferred_io_mmap;
return 0;
}
static void drm_fbdev_cma_defio_fini(struct fb_info *fbi)
{
if (!fbi->fbdefio)
return;
fb_deferred_io_cleanup(fbi);
kfree(fbi->fbdefio);
kfree(fbi->fbops);
}
/*
* For use in a (struct drm_fb_helper_funcs *)->fb_probe callback function that
* needs custom struct drm_framebuffer_funcs, like dirty() for deferred_io use.
*/
int drm_fbdev_cma_create_with_funcs(struct drm_fb_helper *helper,
struct drm_fb_helper_surface_size *sizes,
const struct drm_framebuffer_funcs *funcs)
{
struct drm_fbdev_cma *fbdev_cma = to_fbdev_cma(helper);
struct drm_mode_fb_cmd2 mode_cmd = { 0 };
struct drm_device *dev = helper->dev;
struct drm_gem_cma_object *obj;
struct drm_framebuffer *fb;
unsigned int bytes_per_pixel;
unsigned long offset;
struct fb_info *fbi;
size_t size;
int ret;
DRM_DEBUG_KMS("surface width(%d), height(%d) and bpp(%d)\n",
sizes->surface_width, sizes->surface_height,
sizes->surface_bpp);
bytes_per_pixel = DIV_ROUND_UP(sizes->surface_bpp, 8);
mode_cmd.width = sizes->surface_width;
mode_cmd.height = sizes->surface_height;
mode_cmd.pitches[0] = sizes->surface_width * bytes_per_pixel;
mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
sizes->surface_depth);
size = mode_cmd.pitches[0] * mode_cmd.height;
obj = drm_gem_cma_create(dev, size);
if (IS_ERR(obj))
return -ENOMEM;
fbi = drm_fb_helper_alloc_fbi(helper);
if (IS_ERR(fbi)) {
ret = PTR_ERR(fbi);
goto err_gem_free_object;
}
fbdev_cma->fb = drm_fb_cma_alloc(dev, &mode_cmd, &obj, 1, funcs);
if (IS_ERR(fbdev_cma->fb)) {
dev_err(dev->dev, "Failed to allocate DRM framebuffer.\n");
ret = PTR_ERR(fbdev_cma->fb);
goto err_fb_info_destroy;
}
fb = &fbdev_cma->fb->fb;
helper->fb = fb;
fbi->par = helper;
fbi->flags = FBINFO_FLAG_DEFAULT;
fbi->fbops = &drm_fbdev_cma_ops;
drm_fb_helper_fill_fix(fbi, fb->pitches[0], fb->depth);
drm_fb_helper_fill_var(fbi, helper, sizes->fb_width, sizes->fb_height);
offset = fbi->var.xoffset * bytes_per_pixel;
offset += fbi->var.yoffset * fb->pitches[0];
dev->mode_config.fb_base = (resource_size_t)obj->paddr;
fbi->screen_base = obj->vaddr + offset;
fbi->fix.smem_start = (unsigned long)(obj->paddr + offset);
fbi->screen_size = size;
fbi->fix.smem_len = size;
if (funcs->dirty) {
ret = drm_fbdev_cma_defio_init(fbi, obj);
if (ret)
goto err_cma_destroy;
}
return 0;
err_cma_destroy:
drm_framebuffer_unregister_private(&fbdev_cma->fb->fb);
drm_fb_cma_destroy(&fbdev_cma->fb->fb);
err_fb_info_destroy:
drm_fb_helper_release_fbi(helper);
err_gem_free_object:
drm_gem_object_unreference_unlocked(&obj->base);
return ret;
}
EXPORT_SYMBOL(drm_fbdev_cma_create_with_funcs);
static int drm_fbdev_cma_create(struct drm_fb_helper *helper,
struct drm_fb_helper_surface_size *sizes)
{
return drm_fbdev_cma_create_with_funcs(helper, sizes, &drm_fb_cma_funcs);
}
static const struct drm_fb_helper_funcs drm_fb_cma_helper_funcs = {
.fb_probe = drm_fbdev_cma_create,
};
/**
* drm_fbdev_cma_init_with_funcs() - Allocate and initializes a drm_fbdev_cma struct
* @dev: DRM device
* @preferred_bpp: Preferred bits per pixel for the device
* @num_crtc: Number of CRTCs
* @max_conn_count: Maximum number of connectors
* @funcs: fb helper functions, in particular fb_probe()
*
* Returns a newly allocated drm_fbdev_cma struct or a ERR_PTR.
*/
struct drm_fbdev_cma *drm_fbdev_cma_init_with_funcs(struct drm_device *dev,
unsigned int preferred_bpp, unsigned int num_crtc,
unsigned int max_conn_count, const struct drm_fb_helper_funcs *funcs)
{
struct drm_fbdev_cma *fbdev_cma;
struct drm_fb_helper *helper;
int ret;
fbdev_cma = kzalloc(sizeof(*fbdev_cma), GFP_KERNEL);
if (!fbdev_cma) {
dev_err(dev->dev, "Failed to allocate drm fbdev.\n");
return ERR_PTR(-ENOMEM);
}
helper = &fbdev_cma->fb_helper;
drm_fb_helper_prepare(dev, helper, funcs);
ret = drm_fb_helper_init(dev, helper, num_crtc, max_conn_count);
if (ret < 0) {
dev_err(dev->dev, "Failed to initialize drm fb helper.\n");
goto err_free;
}
ret = drm_fb_helper_single_add_all_connectors(helper);
if (ret < 0) {
dev_err(dev->dev, "Failed to add connectors.\n");
goto err_drm_fb_helper_fini;
}
ret = drm_fb_helper_initial_config(helper, preferred_bpp);
if (ret < 0) {
dev_err(dev->dev, "Failed to set initial hw configuration.\n");
goto err_drm_fb_helper_fini;
}
return fbdev_cma;
err_drm_fb_helper_fini:
drm_fb_helper_fini(helper);
err_free:
kfree(fbdev_cma);
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(drm_fbdev_cma_init_with_funcs);
/**
* drm_fbdev_cma_init() - Allocate and initializes a drm_fbdev_cma struct
* @dev: DRM device
* @preferred_bpp: Preferred bits per pixel for the device
* @num_crtc: Number of CRTCs
* @max_conn_count: Maximum number of connectors
*
* Returns a newly allocated drm_fbdev_cma struct or a ERR_PTR.
*/
struct drm_fbdev_cma *drm_fbdev_cma_init(struct drm_device *dev,
unsigned int preferred_bpp, unsigned int num_crtc,
unsigned int max_conn_count)
{
return drm_fbdev_cma_init_with_funcs(dev, preferred_bpp, num_crtc,
max_conn_count, &drm_fb_cma_helper_funcs);
}
EXPORT_SYMBOL_GPL(drm_fbdev_cma_init);
/**
* drm_fbdev_cma_fini() - Free drm_fbdev_cma struct
* @fbdev_cma: The drm_fbdev_cma struct
*/
void drm_fbdev_cma_fini(struct drm_fbdev_cma *fbdev_cma)
{
drm_fb_helper_unregister_fbi(&fbdev_cma->fb_helper);
drm_fbdev_cma_defio_fini(fbdev_cma->fb_helper.fbdev);
drm_fb_helper_release_fbi(&fbdev_cma->fb_helper);
drm: revamp framebuffer cleanup interfaces We have two classes of framebuffer - Created by the driver (atm only for fbdev), and the driver holds onto the last reference count until destruction. - Created by userspace and associated with a given fd. These framebuffers will be reaped when their assoiciated fb is closed. Now these two cases are set up differently, the framebuffers are on different lists and hence destruction needs to clean up different things. Also, for userspace framebuffers we remove them from any current usage, whereas for internal framebuffers it is assumed that the driver has done this already. Long story short, we need two different ways to cleanup such drivers. Three functions are involved in total: - drm_framebuffer_remove: Convenience function which removes the fb from all active usage and then drops the passed-in reference. - drm_framebuffer_unregister_private: Will remove driver-private framebuffers from relevant lists and drop the corresponding references. Should be called for driver-private framebuffers before dropping the last reference (or like for a lot of the drivers where the fbdev is embedded someplace else, before doing the cleanup manually). - drm_framebuffer_cleanup: Final cleanup for both classes of fbs, should be called by the driver's ->destroy callback once the last reference is gone. This patch just rolls out the new interfaces and updates all drivers (by adding calls to drm_framebuffer_unregister_private at all the right places)- no functional changes yet. Follow-on patches will move drm core code around and update the lifetime management for framebuffers, so that we are no longer required to keep framebuffers alive by locking mode_config.mutex. I've also updated the kerneldoc already. vmwgfx seems to again be a bit special, at least I haven't figured out how the fbdev support in that driver works. It smells like it's external though. v2: The i915 driver creates another private framebuffer in the load-detect code. Adjust its cleanup code, too. Reviewed-by: Rob Clark <rob@ti.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-12-10 19:42:17 +00:00
if (fbdev_cma->fb) {
drm_framebuffer_unregister_private(&fbdev_cma->fb->fb);
drm_fb_cma_destroy(&fbdev_cma->fb->fb);
drm: revamp framebuffer cleanup interfaces We have two classes of framebuffer - Created by the driver (atm only for fbdev), and the driver holds onto the last reference count until destruction. - Created by userspace and associated with a given fd. These framebuffers will be reaped when their assoiciated fb is closed. Now these two cases are set up differently, the framebuffers are on different lists and hence destruction needs to clean up different things. Also, for userspace framebuffers we remove them from any current usage, whereas for internal framebuffers it is assumed that the driver has done this already. Long story short, we need two different ways to cleanup such drivers. Three functions are involved in total: - drm_framebuffer_remove: Convenience function which removes the fb from all active usage and then drops the passed-in reference. - drm_framebuffer_unregister_private: Will remove driver-private framebuffers from relevant lists and drop the corresponding references. Should be called for driver-private framebuffers before dropping the last reference (or like for a lot of the drivers where the fbdev is embedded someplace else, before doing the cleanup manually). - drm_framebuffer_cleanup: Final cleanup for both classes of fbs, should be called by the driver's ->destroy callback once the last reference is gone. This patch just rolls out the new interfaces and updates all drivers (by adding calls to drm_framebuffer_unregister_private at all the right places)- no functional changes yet. Follow-on patches will move drm core code around and update the lifetime management for framebuffers, so that we are no longer required to keep framebuffers alive by locking mode_config.mutex. I've also updated the kerneldoc already. vmwgfx seems to again be a bit special, at least I haven't figured out how the fbdev support in that driver works. It smells like it's external though. v2: The i915 driver creates another private framebuffer in the load-detect code. Adjust its cleanup code, too. Reviewed-by: Rob Clark <rob@ti.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2012-12-10 19:42:17 +00:00
}
drm_fb_helper_fini(&fbdev_cma->fb_helper);
kfree(fbdev_cma);
}
EXPORT_SYMBOL_GPL(drm_fbdev_cma_fini);
/**
* drm_fbdev_cma_restore_mode() - Restores initial framebuffer mode
* @fbdev_cma: The drm_fbdev_cma struct, may be NULL
*
* This function is usually called from the DRM drivers lastclose callback.
*/
void drm_fbdev_cma_restore_mode(struct drm_fbdev_cma *fbdev_cma)
{
if (fbdev_cma)
drm_fb_helper_restore_fbdev_mode_unlocked(&fbdev_cma->fb_helper);
}
EXPORT_SYMBOL_GPL(drm_fbdev_cma_restore_mode);
/**
* drm_fbdev_cma_hotplug_event() - Poll for hotpulug events
* @fbdev_cma: The drm_fbdev_cma struct, may be NULL
*
* This function is usually called from the DRM drivers output_poll_changed
* callback.
*/
void drm_fbdev_cma_hotplug_event(struct drm_fbdev_cma *fbdev_cma)
{
if (fbdev_cma)
drm_fb_helper_hotplug_event(&fbdev_cma->fb_helper);
}
EXPORT_SYMBOL_GPL(drm_fbdev_cma_hotplug_event);