drm_fb_helper.c

   1/*
   2 * Copyright (c) 2006-2009 Red Hat Inc.
   3 * Copyright (c) 2006-2008 Intel Corporation
   4 * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
   5 *
   6 * DRM framebuffer helper functions
   7 *
   8 * Permission to use, copy, modify, distribute, and sell this software and its
   9 * documentation for any purpose is hereby granted without fee, provided that
  10 * the above copyright notice appear in all copies and that both that copyright
  11 * notice and this permission notice appear in supporting documentation, and
  12 * that the name of the copyright holders not be used in advertising or
  13 * publicity pertaining to distribution of the software without specific,
  14 * written prior permission.  The copyright holders make no representations
  15 * about the suitability of this software for any purpose.  It is provided "as
  16 * is" without express or implied warranty.
  17 *
  18 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  19 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  20 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  21 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  22 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  23 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  24 * OF THIS SOFTWARE.
  25 *
  26 * Authors:
  27 *      Dave Airlie <airlied@linux.ie>
  28 *      Jesse Barnes <jesse.barnes@intel.com>
  29 */
  30#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  31
  32#include <linux/console.h>
  33#include <linux/export.h>
  34
  35#include <drm/drm_atomic.h>
  36#include <drm/drm_drv.h>
  37#include <drm/drm_fb_helper.h>
  38#include <drm/drm_fourcc.h>
  39#include <drm/drm_framebuffer.h>
  40#include <drm/drm_modeset_helper_vtables.h>
  41#include <drm/drm_print.h>
  42#include <drm/drm_vblank.h>
  43
  44#include "drm_internal.h"
  45#include "drm_crtc_internal.h"
  46
  47static bool drm_fbdev_emulation = true;
  48module_param_named(fbdev_emulation, drm_fbdev_emulation, bool, 0600);
  49MODULE_PARM_DESC(fbdev_emulation,
  50		 "Enable legacy fbdev emulation [default=true]");
  51
  52static int drm_fbdev_overalloc = CONFIG_DRM_FBDEV_OVERALLOC;
  53module_param(drm_fbdev_overalloc, int, 0444);
  54MODULE_PARM_DESC(drm_fbdev_overalloc,
  55		 "Overallocation of the fbdev buffer (%) [default="
  56		 __MODULE_STRING(CONFIG_DRM_FBDEV_OVERALLOC) "]");
  57
  58/*
  59 * In order to keep user-space compatibility, we want in certain use-cases
  60 * to keep leaking the fbdev physical address to the user-space program
  61 * handling the fbdev buffer.
  62 *
  63 * This is a bad habit, essentially kept to support closed-source OpenGL
  64 * drivers that should really be moved into open-source upstream projects
  65 * instead of using legacy physical addresses in user space to communicate
  66 * with other out-of-tree kernel modules.
  67 *
  68 * This module_param *should* be removed as soon as possible and be
  69 * considered as a broken and legacy behaviour from a modern fbdev device.
  70 */
  71static bool drm_leak_fbdev_smem;
  72#if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM)
  73module_param_unsafe(drm_leak_fbdev_smem, bool, 0600);
  74MODULE_PARM_DESC(drm_leak_fbdev_smem,
  75		 "Allow unsafe leaking fbdev physical smem address [default=false]");
  76#endif
  77
  78static LIST_HEAD(kernel_fb_helper_list);
  79static DEFINE_MUTEX(kernel_fb_helper_lock);
  80
  81/**
  82 * DOC: fbdev helpers
  83 *
  84 * The fb helper functions are useful to provide an fbdev on top of a drm kernel
  85 * mode setting driver. They can be used mostly independently from the crtc
  86 * helper functions used by many drivers to implement the kernel mode setting
  87 * interfaces. Drivers that use one of the shared memory managers, TTM, SHMEM,
  88 * DMA, should instead use the corresponding fbdev emulation.
  89 *
  90 * For suspend/resume consider using drm_mode_config_helper_suspend() and
  91 * drm_mode_config_helper_resume() which takes care of fbdev as well.
  92 *
  93 * All other functions exported by the fb helper library can be used to
  94 * implement the fbdev driver interface by the driver.
  95 *
  96 * It is possible, though perhaps somewhat tricky, to implement race-free
  97 * hotplug detection using the fbdev helpers. The drm_fb_helper_prepare()
  98 * helper must be called first to initialize the minimum required to make
  99 * hotplug detection work. Drivers also need to make sure to properly set up
 100 * the &drm_mode_config.funcs member. After calling drm_kms_helper_poll_init()
 101 * it is safe to enable interrupts and start processing hotplug events. At the
 102 * same time, drivers should initialize all modeset objects such as CRTCs,
 103 * encoders and connectors. To finish up the fbdev helper initialization, the
 104 * drm_fb_helper_init() function is called. To probe for all attached displays
 105 * and set up an initial configuration using the detected hardware, drivers
 106 * should call drm_fb_helper_initial_config().
 107 *
 108 * If &drm_framebuffer_funcs.dirty is set, the
 109 * drm_fb_helper_{cfb,sys}_{write,fillrect,copyarea,imageblit} functions will
 110 * accumulate changes and schedule &drm_fb_helper.dirty_work to run right
 111 * away. This worker then calls the dirty() function ensuring that it will
 112 * always run in process context since the fb_*() function could be running in
 113 * atomic context. If drm_fb_helper_deferred_io() is used as the deferred_io
 114 * callback it will also schedule dirty_work with the damage collected from the
 115 * mmap page writes.
 116 */
 117
 118static void drm_fb_helper_restore_lut_atomic(struct drm_crtc *crtc)
 119{
 120	uint16_t *r_base, *g_base, *b_base;
 121
 122	if (crtc->funcs->gamma_set == NULL)
 123		return;
 124
 125	r_base = crtc->gamma_store;
 126	g_base = r_base + crtc->gamma_size;
 127	b_base = g_base + crtc->gamma_size;
 128
 129	crtc->funcs->gamma_set(crtc, r_base, g_base, b_base,
 130			       crtc->gamma_size, NULL);
 131}
 132
 133/**
 134 * drm_fb_helper_debug_enter - implementation for &fb_ops.fb_debug_enter
 135 * @info: fbdev registered by the helper
 136 */
 137int drm_fb_helper_debug_enter(struct fb_info *info)
 138{
 139	struct drm_fb_helper *helper = info->par;
 140	const struct drm_crtc_helper_funcs *funcs;
 141	struct drm_mode_set *mode_set;
 142
 143	list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
 144		mutex_lock(&helper->client.modeset_mutex);
 145		drm_client_for_each_modeset(mode_set, &helper->client) {
 146			if (!mode_set->crtc->enabled)
 147				continue;
 148
 149			funcs =	mode_set->crtc->helper_private;
 150			if (funcs->mode_set_base_atomic == NULL)
 151				continue;
 152
 153			if (drm_drv_uses_atomic_modeset(mode_set->crtc->dev))
 154				continue;
 155
 156			funcs->mode_set_base_atomic(mode_set->crtc,
 157						    mode_set->fb,
 158						    mode_set->x,
 159						    mode_set->y,
 160						    ENTER_ATOMIC_MODE_SET);
 161		}
 162		mutex_unlock(&helper->client.modeset_mutex);
 163	}
 164
 165	return 0;
 166}
 167EXPORT_SYMBOL(drm_fb_helper_debug_enter);
 168
 169/**
 170 * drm_fb_helper_debug_leave - implementation for &fb_ops.fb_debug_leave
 171 * @info: fbdev registered by the helper
 172 */
 173int drm_fb_helper_debug_leave(struct fb_info *info)
 174{
 175	struct drm_fb_helper *helper = info->par;
 176	struct drm_client_dev *client = &helper->client;
 177	struct drm_device *dev = helper->dev;
 178	struct drm_crtc *crtc;
 179	const struct drm_crtc_helper_funcs *funcs;
 180	struct drm_mode_set *mode_set;
 181	struct drm_framebuffer *fb;
 182
 183	mutex_lock(&client->modeset_mutex);
 184	drm_client_for_each_modeset(mode_set, client) {
 185		crtc = mode_set->crtc;
 186		if (drm_drv_uses_atomic_modeset(crtc->dev))
 187			continue;
 188
 189		funcs = crtc->helper_private;
 190		fb = crtc->primary->fb;
 191
 192		if (!crtc->enabled)
 193			continue;
 194
 195		if (!fb) {
 196			drm_err(dev, "no fb to restore?\n");
 197			continue;
 198		}
 199
 200		if (funcs->mode_set_base_atomic == NULL)
 201			continue;
 202
 203		drm_fb_helper_restore_lut_atomic(mode_set->crtc);
 204		funcs->mode_set_base_atomic(mode_set->crtc, fb, crtc->x,
 205					    crtc->y, LEAVE_ATOMIC_MODE_SET);
 206	}
 207	mutex_unlock(&client->modeset_mutex);
 208
 209	return 0;
 210}
 211EXPORT_SYMBOL(drm_fb_helper_debug_leave);
 212
 213static int
 214__drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper,
 215					    bool force)
 216{
 217	bool do_delayed;
 218	int ret;
 219
 220	if (!drm_fbdev_emulation || !fb_helper)
 221		return -ENODEV;
 222
 223	if (READ_ONCE(fb_helper->deferred_setup))
 224		return 0;
 225
 226	mutex_lock(&fb_helper->lock);
 227	if (force) {
 228		/*
 229		 * Yes this is the _locked version which expects the master lock
 230		 * to be held. But for forced restores we're intentionally
 231		 * racing here, see drm_fb_helper_set_par().
 232		 */
 233		ret = drm_client_modeset_commit_locked(&fb_helper->client);
 234	} else {
 235		ret = drm_client_modeset_commit(&fb_helper->client);
 236	}
 237
 238	do_delayed = fb_helper->delayed_hotplug;
 239	if (do_delayed)
 240		fb_helper->delayed_hotplug = false;
 241	mutex_unlock(&fb_helper->lock);
 242
 243	if (do_delayed)
 244		drm_fb_helper_hotplug_event(fb_helper);
 245
 246	if (fb_helper->funcs->fb_restore)
 247		fb_helper->funcs->fb_restore(fb_helper);
 248
 249	return ret;
 250}
 251
 252/**
 253 * drm_fb_helper_restore_fbdev_mode_unlocked - restore fbdev configuration
 254 * @fb_helper: driver-allocated fbdev helper, can be NULL
 255 * @force: ignore present DRM master
 256 *
 257 * This helper should be called from fbdev emulation's &drm_client_funcs.restore
 258 * callback. It ensures that the user isn't greeted with a black screen when the
 259 * userspace compositor releases the display device.
 260 *
 261 * Returns:
 262 * 0 on success, or a negative errno code otherwise.
 263 */
 264int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper, bool force)
 265{
 266	return __drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper, force);
 267}
 268EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode_unlocked);
 269
 270static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode)
 271{
 272	struct drm_fb_helper *fb_helper = info->par;
 273
 274	mutex_lock(&fb_helper->lock);
 275	drm_client_modeset_dpms(&fb_helper->client, dpms_mode);
 276	mutex_unlock(&fb_helper->lock);
 277}
 278
 279/**
 280 * drm_fb_helper_blank - implementation for &fb_ops.fb_blank
 281 * @blank: desired blanking state
 282 * @info: fbdev registered by the helper
 283 */
 284int drm_fb_helper_blank(int blank, struct fb_info *info)
 285{
 286	if (oops_in_progress)
 287		return -EBUSY;
 288
 289	switch (blank) {
 290	/* Display: On; HSync: On, VSync: On */
 291	case FB_BLANK_UNBLANK:
 292		drm_fb_helper_dpms(info, DRM_MODE_DPMS_ON);
 293		break;
 294	/* Display: Off; HSync: On, VSync: On */
 295	case FB_BLANK_NORMAL:
 296		drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
 297		break;
 298	/* Display: Off; HSync: Off, VSync: On */
 299	case FB_BLANK_HSYNC_SUSPEND:
 300		drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
 301		break;
 302	/* Display: Off; HSync: On, VSync: Off */
 303	case FB_BLANK_VSYNC_SUSPEND:
 304		drm_fb_helper_dpms(info, DRM_MODE_DPMS_SUSPEND);
 305		break;
 306	/* Display: Off; HSync: Off, VSync: Off */
 307	case FB_BLANK_POWERDOWN:
 308		drm_fb_helper_dpms(info, DRM_MODE_DPMS_OFF);
 309		break;
 310	}
 311	return 0;
 312}
 313EXPORT_SYMBOL(drm_fb_helper_blank);
 314
 315static void drm_fb_helper_resume_worker(struct work_struct *work)
 316{
 317	struct drm_fb_helper *helper = container_of(work, struct drm_fb_helper,
 318						    resume_work);
 319
 320	console_lock();
 321	fb_set_suspend(helper->info, 0);
 322	console_unlock();
 323}
 324
 325static void drm_fb_helper_fb_dirty(struct drm_fb_helper *helper)
 326{
 327	struct drm_device *dev = helper->dev;
 328	struct drm_clip_rect *clip = &helper->damage_clip;
 329	struct drm_clip_rect clip_copy;
 330	unsigned long flags;
 331	int ret;
 332
 333	mutex_lock(&helper->lock);
 334	drm_client_modeset_wait_for_vblank(&helper->client, 0);
 335	mutex_unlock(&helper->lock);
 336
 337	if (drm_WARN_ON_ONCE(dev, !helper->funcs->fb_dirty))
 338		return;
 339
 340	spin_lock_irqsave(&helper->damage_lock, flags);
 341	clip_copy = *clip;
 342	clip->x1 = clip->y1 = ~0;
 343	clip->x2 = clip->y2 = 0;
 344	spin_unlock_irqrestore(&helper->damage_lock, flags);
 345
 346	ret = helper->funcs->fb_dirty(helper, &clip_copy);
 347	if (ret)
 348		goto err;
 349
 350	return;
 351
 352err:
 353	/*
 354	 * Restore damage clip rectangle on errors. The next run
 355	 * of the damage worker will perform the update.
 356	 */
 357	spin_lock_irqsave(&helper->damage_lock, flags);
 358	clip->x1 = min_t(u32, clip->x1, clip_copy.x1);
 359	clip->y1 = min_t(u32, clip->y1, clip_copy.y1);
 360	clip->x2 = max_t(u32, clip->x2, clip_copy.x2);
 361	clip->y2 = max_t(u32, clip->y2, clip_copy.y2);
 362	spin_unlock_irqrestore(&helper->damage_lock, flags);
 363}
 364
 365static void drm_fb_helper_damage_work(struct work_struct *work)
 366{
 367	struct drm_fb_helper *helper = container_of(work, struct drm_fb_helper, damage_work);
 368
 369	if (helper->info->state != FBINFO_STATE_RUNNING)
 370		return;
 371
 372	drm_fb_helper_fb_dirty(helper);
 373}
 374
 375/**
 376 * drm_fb_helper_prepare - setup a drm_fb_helper structure
 377 * @dev: DRM device
 378 * @helper: driver-allocated fbdev helper structure to set up
 379 * @preferred_bpp: Preferred bits per pixel for the device.
 380 * @funcs: pointer to structure of functions associate with this helper
 381 *
 382 * Sets up the bare minimum to make the framebuffer helper usable. This is
 383 * useful to implement race-free initialization of the polling helpers.
 384 */
 385void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
 386			   unsigned int preferred_bpp,
 387			   const struct drm_fb_helper_funcs *funcs)
 388{
 389	/*
 390	 * Pick a preferred bpp of 32 if no value has been given. This
 391	 * will select XRGB8888 for the framebuffer formats. All drivers
 392	 * have to support XRGB8888 for backwards compatibility with legacy
 393	 * userspace, so it's the safe choice here.
 394	 *
 395	 * TODO: Replace struct drm_mode_config.preferred_depth and this
 396	 *       bpp value with a preferred format that is given as struct
 397	 *       drm_format_info. Then derive all other values from the
 398	 *       format.
 399	 */
 400	if (!preferred_bpp)
 401		preferred_bpp = 32;
 402
 403	INIT_LIST_HEAD(&helper->kernel_fb_list);
 404	spin_lock_init(&helper->damage_lock);
 405	INIT_WORK(&helper->resume_work, drm_fb_helper_resume_worker);
 406	INIT_WORK(&helper->damage_work, drm_fb_helper_damage_work);
 407	helper->damage_clip.x1 = helper->damage_clip.y1 = ~0;
 408	mutex_init(&helper->lock);
 409	helper->funcs = funcs;
 410	helper->dev = dev;
 411	helper->preferred_bpp = preferred_bpp;
 412}
 413EXPORT_SYMBOL(drm_fb_helper_prepare);
 414
 415/**
 416 * drm_fb_helper_unprepare - clean up a drm_fb_helper structure
 417 * @fb_helper: driver-allocated fbdev helper structure to set up
 418 *
 419 * Cleans up the framebuffer helper. Inverse of drm_fb_helper_prepare().
 420 */
 421void drm_fb_helper_unprepare(struct drm_fb_helper *fb_helper)
 422{
 423	mutex_destroy(&fb_helper->lock);
 424}
 425EXPORT_SYMBOL(drm_fb_helper_unprepare);
 426
 427/**
 428 * drm_fb_helper_init - initialize a &struct drm_fb_helper
 429 * @dev: drm device
 430 * @fb_helper: driver-allocated fbdev helper structure to initialize
 431 *
 432 * This allocates the structures for the fbdev helper with the given limits.
 433 * Note that this won't yet touch the hardware (through the driver interfaces)
 434 * nor register the fbdev. This is only done in drm_fb_helper_initial_config()
 435 * to allow driver writes more control over the exact init sequence.
 436 *
 437 * Drivers must call drm_fb_helper_prepare() before calling this function.
 438 *
 439 * RETURNS:
 440 * Zero if everything went ok, nonzero otherwise.
 441 */
 442int drm_fb_helper_init(struct drm_device *dev,
 443		       struct drm_fb_helper *fb_helper)
 444{
 445	int ret;
 446
 447	/*
 448	 * If this is not the generic fbdev client, initialize a drm_client
 449	 * without callbacks so we can use the modesets.
 450	 */
 451	if (!fb_helper->client.funcs) {
 452		ret = drm_client_init(dev, &fb_helper->client, "drm_fb_helper", NULL);
 453		if (ret)
 454			return ret;
 455	}
 456
 457	dev->fb_helper = fb_helper;
 458
 459	return 0;
 460}
 461EXPORT_SYMBOL(drm_fb_helper_init);
 462
 463static struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
 464{
 465	struct device *dev = fb_helper->dev->dev;
 466	struct fb_info *info;
 467	int ret;
 468
 469	info = framebuffer_alloc(0, dev);
 470	if (!info)
 471		return ERR_PTR(-ENOMEM);
 472
 473	if (!drm_leak_fbdev_smem)
 474		info->flags |= FBINFO_HIDE_SMEM_START;
 475
 476	ret = fb_alloc_cmap(&info->cmap, 256, 0);
 477	if (ret)
 478		goto err_release;
 479
 480	fb_helper->info = info;
 481	info->skip_vt_switch = true;
 482
 483	info->skip_panic = drm_panic_is_enabled(fb_helper->dev);
 484	return info;
 485
 486err_release:
 487	framebuffer_release(info);
 488	return ERR_PTR(ret);
 489}
 490
 491static void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
 492{
 493	struct fb_info *info = fb_helper->info;
 494
 495	if (!info)
 496		return;
 497
 498	fb_helper->info = NULL;
 499
 500	if (info->cmap.len)
 501		fb_dealloc_cmap(&info->cmap);
 502	framebuffer_release(info);
 503}
 504
 505/**
 506 * drm_fb_helper_unregister_info - unregister fb_info framebuffer device
 507 * @fb_helper: driver-allocated fbdev helper, must not be NULL
 508 *
 509 * A wrapper around unregister_framebuffer, to release the fb_info
 510 * framebuffer device. This must be called before releasing all resources for
 511 * @fb_helper by calling drm_fb_helper_fini().
 512 */
 513void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper)
 514{
 515	unregister_framebuffer(fb_helper->info);
 516}
 517EXPORT_SYMBOL(drm_fb_helper_unregister_info);
 518
 519/**
 520 * drm_fb_helper_fini - finialize a &struct drm_fb_helper
 521 * @fb_helper: driver-allocated fbdev helper, can be NULL
 522 *
 523 * This cleans up all remaining resources associated with @fb_helper.
 524 */
 525void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
 526{
 527	if (!fb_helper)
 528		return;
 529
 530	fb_helper->dev->fb_helper = NULL;
 531
 532	if (!drm_fbdev_emulation)
 533		return;
 534
 535	cancel_work_sync(&fb_helper->resume_work);
 536	cancel_work_sync(&fb_helper->damage_work);
 537
 538	drm_fb_helper_release_info(fb_helper);
 539
 540	mutex_lock(&kernel_fb_helper_lock);
 541	if (!list_empty(&fb_helper->kernel_fb_list))
 542		list_del(&fb_helper->kernel_fb_list);
 543	mutex_unlock(&kernel_fb_helper_lock);
 544
 545	if (!fb_helper->client.funcs)
 546		drm_client_release(&fb_helper->client);
 547}
 548EXPORT_SYMBOL(drm_fb_helper_fini);
 549
 550static void drm_fb_helper_add_damage_clip(struct drm_fb_helper *helper, u32 x, u32 y,
 551					  u32 width, u32 height)
 552{
 553	struct drm_clip_rect *clip = &helper->damage_clip;
 554	unsigned long flags;
 555
 556	spin_lock_irqsave(&helper->damage_lock, flags);
 557	clip->x1 = min_t(u32, clip->x1, x);
 558	clip->y1 = min_t(u32, clip->y1, y);
 559	clip->x2 = max_t(u32, clip->x2, x + width);
 560	clip->y2 = max_t(u32, clip->y2, y + height);
 561	spin_unlock_irqrestore(&helper->damage_lock, flags);
 562}
 563
 564static void drm_fb_helper_damage(struct drm_fb_helper *helper, u32 x, u32 y,
 565				 u32 width, u32 height)
 566{
 567	/*
 568	 * This function may be invoked by panic() to flush the frame
 569	 * buffer, where all CPUs except the panic CPU are stopped.
 570	 * During the following schedule_work(), the panic CPU needs
 571	 * the worker_pool lock, which might be held by a stopped CPU,
 572	 * causing schedule_work() and panic() to block. Return early on
 573	 * oops_in_progress to prevent this blocking.
 574	 */
 575	if (oops_in_progress)
 576		return;
 577
 578	drm_fb_helper_add_damage_clip(helper, x, y, width, height);
 579
 580	schedule_work(&helper->damage_work);
 581}
 582
 583/*
 584 * Convert memory region into area of scanlines and pixels per
 585 * scanline. The parameters off and len must not reach beyond
 586 * the end of the framebuffer.
 587 */
 588static void drm_fb_helper_memory_range_to_clip(struct fb_info *info, off_t off, size_t len,
 589					       struct drm_rect *clip)
 590{
 591	u32 line_length = info->fix.line_length;
 592	u32 fb_height = info->var.yres;
 593	off_t end = off + len;
 594	u32 x1 = 0;
 595	u32 y1 = off / line_length;
 596	u32 x2 = info->var.xres;
 597	u32 y2 = DIV_ROUND_UP(end, line_length);
 598
 599	/* Don't allow any of them beyond the bottom bound of display area */
 600	if (y1 > fb_height)
 601		y1 = fb_height;
 602	if (y2 > fb_height)
 603		y2 = fb_height;
 604
 605	if ((y2 - y1) == 1) {
 606		/*
 607		 * We've only written to a single scanline. Try to reduce
 608		 * the number of horizontal pixels that need an update.
 609		 */
 610		off_t bit_off = (off % line_length) * 8;
 611		off_t bit_end = (end % line_length) * 8;
 612
 613		x1 = bit_off / info->var.bits_per_pixel;
 614		x2 = DIV_ROUND_UP(bit_end, info->var.bits_per_pixel);
 615	}
 616
 617	drm_rect_init(clip, x1, y1, x2 - x1, y2 - y1);
 618}
 619
 620/* Don't use in new code. */
 621void drm_fb_helper_damage_range(struct fb_info *info, off_t off, size_t len)
 622{
 623	struct drm_fb_helper *fb_helper = info->par;
 624	struct drm_rect damage_area;
 625
 626	drm_fb_helper_memory_range_to_clip(info, off, len, &damage_area);
 627	drm_fb_helper_damage(fb_helper, damage_area.x1, damage_area.y1,
 628			     drm_rect_width(&damage_area),
 629			     drm_rect_height(&damage_area));
 630}
 631EXPORT_SYMBOL(drm_fb_helper_damage_range);
 632
 633/* Don't use in new code. */
 634void drm_fb_helper_damage_area(struct fb_info *info, u32 x, u32 y, u32 width, u32 height)
 635{
 636	struct drm_fb_helper *fb_helper = info->par;
 637
 638	drm_fb_helper_damage(fb_helper, x, y, width, height);
 639}
 640EXPORT_SYMBOL(drm_fb_helper_damage_area);
 641
 642#ifdef CONFIG_FB_DEFERRED_IO
 643/**
 644 * drm_fb_helper_deferred_io() - fbdev deferred_io callback function
 645 * @info: fb_info struct pointer
 646 * @pagereflist: list of mmap framebuffer pages that have to be flushed
 647 *
 648 * This function is used as the &fb_deferred_io.deferred_io
 649 * callback function for flushing the fbdev mmap writes.
 650 */
 651void drm_fb_helper_deferred_io(struct fb_info *info, struct list_head *pagereflist)
 652{
 653	struct drm_fb_helper *helper = info->par;
 654	unsigned long start, end, min_off, max_off, total_size;
 655	struct fb_deferred_io_pageref *pageref;
 656	struct drm_rect damage_area;
 657
 658	min_off = ULONG_MAX;
 659	max_off = 0;
 660	list_for_each_entry(pageref, pagereflist, list) {
 661		start = pageref->offset;
 662		end = start + PAGE_SIZE;
 663		min_off = min(min_off, start);
 664		max_off = max(max_off, end);
 665	}
 666
 667	/*
 668	 * As we can only track pages, we might reach beyond the end
 669	 * of the screen and account for non-existing scanlines. Hence,
 670	 * keep the covered memory area within the screen buffer.
 671	 */
 672	if (info->screen_size)
 673		total_size = info->screen_size;
 674	else
 675		total_size = info->fix.smem_len;
 676	max_off = min(max_off, total_size);
 677
 678	if (min_off < max_off) {
 679		drm_fb_helper_memory_range_to_clip(info, min_off, max_off - min_off, &damage_area);
 680		drm_fb_helper_damage(helper, damage_area.x1, damage_area.y1,
 681				     drm_rect_width(&damage_area),
 682				     drm_rect_height(&damage_area));
 683	}
 684}
 685EXPORT_SYMBOL(drm_fb_helper_deferred_io);
 686#endif
 687
 688/**
 689 * drm_fb_helper_set_suspend - wrapper around fb_set_suspend
 690 * @fb_helper: driver-allocated fbdev helper, can be NULL
 691 * @suspend: whether to suspend or resume
 692 *
 693 * A wrapper around fb_set_suspend implemented by fbdev core.
 694 * Use drm_fb_helper_set_suspend_unlocked() if you don't need to take
 695 * the lock yourself
 696 */
 697void drm_fb_helper_set_suspend(struct drm_fb_helper *fb_helper, bool suspend)
 698{
 699	if (!fb_helper || !fb_helper->info)
 700		return;
 701
 702	if (fb_helper->funcs->fb_set_suspend)
 703		fb_helper->funcs->fb_set_suspend(fb_helper, suspend);
 704	else
 705		fb_set_suspend(fb_helper->info, suspend);
 706}
 707EXPORT_SYMBOL(drm_fb_helper_set_suspend);
 708
 709/**
 710 * drm_fb_helper_set_suspend_unlocked - wrapper around fb_set_suspend that also
 711 *                                      takes the console lock
 712 * @fb_helper: driver-allocated fbdev helper, can be NULL
 713 * @suspend: whether to suspend or resume
 714 *
 715 * A wrapper around fb_set_suspend() that takes the console lock. If the lock
 716 * isn't available on resume, a worker is tasked with waiting for the lock
 717 * to become available. The console lock can be pretty contented on resume
 718 * due to all the printk activity.
 719 *
 720 * This function can be called multiple times with the same state since
 721 * &fb_info.state is checked to see if fbdev is running or not before locking.
 722 *
 723 * Use drm_fb_helper_set_suspend() if you need to take the lock yourself.
 724 */
 725void drm_fb_helper_set_suspend_unlocked(struct drm_fb_helper *fb_helper,
 726					bool suspend)
 727{
 728	if (!fb_helper || !fb_helper->info)
 729		return;
 730
 731	/* make sure there's no pending/ongoing resume */
 732	flush_work(&fb_helper->resume_work);
 733
 734	if (suspend) {
 735		if (fb_helper->info->state != FBINFO_STATE_RUNNING)
 736			return;
 737
 738		/*
 739		 * Cancel pending damage work. During GPU reset, VBlank
 740		 * interrupts are disabled and drm_fb_helper_fb_dirty()
 741		 * would wait for VBlank timeout otherwise.
 742		 */
 743		cancel_work_sync(&fb_helper->damage_work);
 744
 745		console_lock();
 746
 747	} else {
 748		if (fb_helper->info->state == FBINFO_STATE_RUNNING)
 749			return;
 750
 751		if (!console_trylock()) {
 752			schedule_work(&fb_helper->resume_work);
 753			return;
 754		}
 755	}
 756
 757	drm_fb_helper_set_suspend(fb_helper, suspend);
 758	console_unlock();
 759}
 760EXPORT_SYMBOL(drm_fb_helper_set_suspend_unlocked);
 761
 762static int setcmap_pseudo_palette(struct fb_cmap *cmap, struct fb_info *info)
 763{
 764	u32 *palette = (u32 *)info->pseudo_palette;
 765	int i;
 766
 767	if (cmap->start + cmap->len > 16)
 768		return -EINVAL;
 769
 770	for (i = 0; i < cmap->len; ++i) {
 771		u16 red = cmap->red[i];
 772		u16 green = cmap->green[i];
 773		u16 blue = cmap->blue[i];
 774		u32 value;
 775
 776		red >>= 16 - info->var.red.length;
 777		green >>= 16 - info->var.green.length;
 778		blue >>= 16 - info->var.blue.length;
 779		value = (red << info->var.red.offset) |
 780			(green << info->var.green.offset) |
 781			(blue << info->var.blue.offset);
 782		if (info->var.transp.length > 0) {
 783			u32 mask = (1 << info->var.transp.length) - 1;
 784
 785			mask <<= info->var.transp.offset;
 786			value |= mask;
 787		}
 788		palette[cmap->start + i] = value;
 789	}
 790
 791	return 0;
 792}
 793
 794static int setcmap_legacy(struct fb_cmap *cmap, struct fb_info *info)
 795{
 796	struct drm_fb_helper *fb_helper = info->par;
 797	struct drm_mode_set *modeset;
 798	struct drm_crtc *crtc;
 799	u16 *r, *g, *b;
 800	int ret = 0;
 801
 802	drm_modeset_lock_all(fb_helper->dev);
 803	drm_client_for_each_modeset(modeset, &fb_helper->client) {
 804		crtc = modeset->crtc;
 805		if (!crtc->funcs->gamma_set || !crtc->gamma_size) {
 806			ret = -EINVAL;
 807			goto out;
 808		}
 809
 810		if (cmap->start + cmap->len > crtc->gamma_size) {
 811			ret = -EINVAL;
 812			goto out;
 813		}
 814
 815		r = crtc->gamma_store;
 816		g = r + crtc->gamma_size;
 817		b = g + crtc->gamma_size;
 818
 819		memcpy(r + cmap->start, cmap->red, cmap->len * sizeof(*r));
 820		memcpy(g + cmap->start, cmap->green, cmap->len * sizeof(*g));
 821		memcpy(b + cmap->start, cmap->blue, cmap->len * sizeof(*b));
 822
 823		ret = crtc->funcs->gamma_set(crtc, r, g, b,
 824					     crtc->gamma_size, NULL);
 825		if (ret)
 826			goto out;
 827	}
 828out:
 829	drm_modeset_unlock_all(fb_helper->dev);
 830
 831	return ret;
 832}
 833
 834static struct drm_property_blob *setcmap_new_gamma_lut(struct drm_crtc *crtc,
 835						       struct fb_cmap *cmap)
 836{
 837	struct drm_device *dev = crtc->dev;
 838	struct drm_property_blob *gamma_lut;
 839	struct drm_color_lut *lut;
 840	int size = crtc->gamma_size;
 841	int i;
 842
 843	if (!size || cmap->start + cmap->len > size)
 844		return ERR_PTR(-EINVAL);
 845
 846	gamma_lut = drm_property_create_blob(dev, sizeof(*lut) * size, NULL);
 847	if (IS_ERR(gamma_lut))
 848		return gamma_lut;
 849
 850	lut = gamma_lut->data;
 851	if (cmap->start || cmap->len != size) {
 852		u16 *r = crtc->gamma_store;
 853		u16 *g = r + crtc->gamma_size;
 854		u16 *b = g + crtc->gamma_size;
 855
 856		for (i = 0; i < cmap->start; i++) {
 857			lut[i].red = r[i];
 858			lut[i].green = g[i];
 859			lut[i].blue = b[i];
 860		}
 861		for (i = cmap->start + cmap->len; i < size; i++) {
 862			lut[i].red = r[i];
 863			lut[i].green = g[i];
 864			lut[i].blue = b[i];
 865		}
 866	}
 867
 868	for (i = 0; i < cmap->len; i++) {
 869		lut[cmap->start + i].red = cmap->red[i];
 870		lut[cmap->start + i].green = cmap->green[i];
 871		lut[cmap->start + i].blue = cmap->blue[i];
 872	}
 873
 874	return gamma_lut;
 875}
 876
 877static int setcmap_atomic(struct fb_cmap *cmap, struct fb_info *info)
 878{
 879	struct drm_fb_helper *fb_helper = info->par;
 880	struct drm_device *dev = fb_helper->dev;
 881	struct drm_property_blob *gamma_lut = NULL;
 882	struct drm_modeset_acquire_ctx ctx;
 883	struct drm_crtc_state *crtc_state;
 884	struct drm_atomic_state *state;
 885	struct drm_mode_set *modeset;
 886	struct drm_crtc *crtc;
 887	u16 *r, *g, *b;
 888	bool replaced;
 889	int ret = 0;
 890
 891	drm_modeset_acquire_init(&ctx, 0);
 892
 893	state = drm_atomic_state_alloc(dev);
 894	if (!state) {
 895		ret = -ENOMEM;
 896		goto out_ctx;
 897	}
 898
 899	state->acquire_ctx = &ctx;
 900retry:
 901	drm_client_for_each_modeset(modeset, &fb_helper->client) {
 902		crtc = modeset->crtc;
 903
 904		if (!gamma_lut)
 905			gamma_lut = setcmap_new_gamma_lut(crtc, cmap);
 906		if (IS_ERR(gamma_lut)) {
 907			ret = PTR_ERR(gamma_lut);
 908			gamma_lut = NULL;
 909			goto out_state;
 910		}
 911
 912		crtc_state = drm_atomic_get_crtc_state(state, crtc);
 913		if (IS_ERR(crtc_state)) {
 914			ret = PTR_ERR(crtc_state);
 915			goto out_state;
 916		}
 917
 918		/*
 919		 * FIXME: This always uses gamma_lut. Some HW have only
 920		 * degamma_lut, in which case we should reset gamma_lut and set
 921		 * degamma_lut. See drm_crtc_legacy_gamma_set().
 922		 */
 923		replaced  = drm_property_replace_blob(&crtc_state->degamma_lut,
 924						      NULL);
 925		replaced |= drm_property_replace_blob(&crtc_state->ctm, NULL);
 926		replaced |= drm_property_replace_blob(&crtc_state->gamma_lut,
 927						      gamma_lut);
 928		crtc_state->color_mgmt_changed |= replaced;
 929	}
 930
 931	ret = drm_atomic_commit(state);
 932	if (ret)
 933		goto out_state;
 934
 935	drm_client_for_each_modeset(modeset, &fb_helper->client) {
 936		crtc = modeset->crtc;
 937
 938		r = crtc->gamma_store;
 939		g = r + crtc->gamma_size;
 940		b = g + crtc->gamma_size;
 941
 942		memcpy(r + cmap->start, cmap->red, cmap->len * sizeof(*r));
 943		memcpy(g + cmap->start, cmap->green, cmap->len * sizeof(*g));
 944		memcpy(b + cmap->start, cmap->blue, cmap->len * sizeof(*b));
 945	}
 946
 947out_state:
 948	if (ret == -EDEADLK)
 949		goto backoff;
 950
 951	drm_property_blob_put(gamma_lut);
 952	drm_atomic_state_put(state);
 953out_ctx:
 954	drm_modeset_drop_locks(&ctx);
 955	drm_modeset_acquire_fini(&ctx);
 956
 957	return ret;
 958
 959backoff:
 960	drm_atomic_state_clear(state);
 961	drm_modeset_backoff(&ctx);
 962	goto retry;
 963}
 964
 965/**
 966 * drm_fb_helper_setcmap - implementation for &fb_ops.fb_setcmap
 967 * @cmap: cmap to set
 968 * @info: fbdev registered by the helper
 969 */
 970int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
 971{
 972	struct drm_fb_helper *fb_helper = info->par;
 973	struct drm_device *dev = fb_helper->dev;
 974	int ret;
 975
 976	if (oops_in_progress)
 977		return -EBUSY;
 978
 979	mutex_lock(&fb_helper->lock);
 980
 981	if (!drm_master_internal_acquire(dev)) {
 982		ret = -EBUSY;
 983		goto unlock;
 984	}
 985
 986	mutex_lock(&fb_helper->client.modeset_mutex);
 987	if (info->fix.visual == FB_VISUAL_TRUECOLOR)
 988		ret = setcmap_pseudo_palette(cmap, info);
 989	else if (drm_drv_uses_atomic_modeset(fb_helper->dev))
 990		ret = setcmap_atomic(cmap, info);
 991	else
 992		ret = setcmap_legacy(cmap, info);
 993	mutex_unlock(&fb_helper->client.modeset_mutex);
 994
 995	drm_master_internal_release(dev);
 996unlock:
 997	mutex_unlock(&fb_helper->lock);
 998
 999	return ret;
1000}
1001EXPORT_SYMBOL(drm_fb_helper_setcmap);
1002
1003/**
1004 * drm_fb_helper_ioctl - legacy ioctl implementation
1005 * @info: fbdev registered by the helper
1006 * @cmd: ioctl command
1007 * @arg: ioctl argument
1008 *
1009 * A helper to implement the standard fbdev ioctl. Only
1010 * FBIO_WAITFORVSYNC is implemented for now.
1011 */
1012int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
1013			unsigned long arg)
1014{
1015	struct drm_fb_helper *fb_helper = info->par;
1016	int ret = 0;
1017
1018	guard(mutex)(&fb_helper->lock);
1019
1020	switch (cmd) {
1021	case FBIO_WAITFORVSYNC:
1022		/*
1023		 * Only consider the first CRTC.
1024		 *
1025		 * This ioctl is supposed to take the CRTC number as
1026		 * an argument, but in fbdev times, what that number
1027		 * was supposed to be was quite unclear, different
1028		 * drivers were passing that argument differently
1029		 * (some by reference, some by value), and most of the
1030		 * userspace applications were just hardcoding 0 as an
1031		 * argument.
1032		 *
1033		 * The first CRTC should be the integrated panel on
1034		 * most drivers, so this is the best choice we can
1035		 * make. If we're not smart enough here, one should
1036		 * just consider switch the userspace to KMS.
1037		 */
1038		ret = drm_client_modeset_wait_for_vblank(&fb_helper->client, 0);
1039		break;
1040	default:
1041		ret = -ENOTTY;
1042	}
1043
1044	return ret;
1045}
1046EXPORT_SYMBOL(drm_fb_helper_ioctl);
1047
1048static bool drm_fb_pixel_format_equal(const struct fb_var_screeninfo *var_1,
1049				      const struct fb_var_screeninfo *var_2)
1050{
1051	return var_1->bits_per_pixel == var_2->bits_per_pixel &&
1052	       var_1->grayscale == var_2->grayscale &&
1053	       var_1->red.offset == var_2->red.offset &&
1054	       var_1->red.length == var_2->red.length &&
1055	       var_1->red.msb_right == var_2->red.msb_right &&
1056	       var_1->green.offset == var_2->green.offset &&
1057	       var_1->green.length == var_2->green.length &&
1058	       var_1->green.msb_right == var_2->green.msb_right &&
1059	       var_1->blue.offset == var_2->blue.offset &&
1060	       var_1->blue.length == var_2->blue.length &&
1061	       var_1->blue.msb_right == var_2->blue.msb_right &&
1062	       var_1->transp.offset == var_2->transp.offset &&
1063	       var_1->transp.length == var_2->transp.length &&
1064	       var_1->transp.msb_right == var_2->transp.msb_right;
1065}
1066
1067static void drm_fb_helper_fill_pixel_fmt(struct fb_var_screeninfo *var,
1068					 const struct drm_format_info *format)
1069{
1070	u8 depth = format->depth;
1071
1072	if (format->is_color_indexed) {
1073		var->red.offset = 0;
1074		var->green.offset = 0;
1075		var->blue.offset = 0;
1076		var->red.length = depth;
1077		var->green.length = depth;
1078		var->blue.length = depth;
1079		var->transp.offset = 0;
1080		var->transp.length = 0;
1081		return;
1082	}
1083
1084	switch (depth) {
1085	case 15:
1086		var->red.offset = 10;
1087		var->green.offset = 5;
1088		var->blue.offset = 0;
1089		var->red.length = 5;
1090		var->green.length = 5;
1091		var->blue.length = 5;
1092		var->transp.offset = 15;
1093		var->transp.length = 1;
1094		break;
1095	case 16:
1096		var->red.offset = 11;
1097		var->green.offset = 5;
1098		var->blue.offset = 0;
1099		var->red.length = 5;
1100		var->green.length = 6;
1101		var->blue.length = 5;
1102		var->transp.offset = 0;
1103		break;
1104	case 24:
1105		var->red.offset = 16;
1106		var->green.offset = 8;
1107		var->blue.offset = 0;
1108		var->red.length = 8;
1109		var->green.length = 8;
1110		var->blue.length = 8;
1111		var->transp.offset = 0;
1112		var->transp.length = 0;
1113		break;
1114	case 32:
1115		var->red.offset = 16;
1116		var->green.offset = 8;
1117		var->blue.offset = 0;
1118		var->red.length = 8;
1119		var->green.length = 8;
1120		var->blue.length = 8;
1121		var->transp.offset = 24;
1122		var->transp.length = 8;
1123		break;
1124	default:
1125		break;
1126	}
1127}
1128
1129static void __fill_var(struct fb_var_screeninfo *var, struct fb_info *info,
1130		       struct drm_framebuffer *fb)
1131{
1132	int i;
1133
1134	var->xres_virtual = fb->width;
1135	var->yres_virtual = fb->height;
1136	var->accel_flags = 0;
1137	var->bits_per_pixel = drm_format_info_bpp(fb->format, 0);
1138
1139	var->height = info->var.height;
1140	var->width = info->var.width;
1141
1142	var->left_margin = var->right_margin = 0;
1143	var->upper_margin = var->lower_margin = 0;
1144	var->hsync_len = var->vsync_len = 0;
1145	var->sync = var->vmode = 0;
1146	var->rotate = 0;
1147	var->colorspace = 0;
1148	for (i = 0; i < 4; i++)
1149		var->reserved[i] = 0;
1150}
1151
1152/**
1153 * drm_fb_helper_check_var - implementation for &fb_ops.fb_check_var
1154 * @var: screeninfo to check
1155 * @info: fbdev registered by the helper
1156 */
1157int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
1158			    struct fb_info *info)
1159{
1160	struct drm_fb_helper *fb_helper = info->par;
1161	struct drm_framebuffer *fb = fb_helper->fb;
1162	const struct drm_format_info *format = fb->format;
1163	struct drm_device *dev = fb_helper->dev;
1164	unsigned int bpp;
1165
1166	if (in_dbg_master())
1167		return -EINVAL;
1168
1169	if (var->pixclock != 0) {
1170		drm_dbg_kms(dev, "fbdev emulation doesn't support changing the pixel clock, value of pixclock is ignored\n");
1171		var->pixclock = 0;
1172	}
1173
1174	switch (format->format) {
1175	case DRM_FORMAT_C1:
1176	case DRM_FORMAT_C2:
1177	case DRM_FORMAT_C4:
1178		/* supported format with sub-byte pixels */
1179		break;
1180
1181	default:
1182		if ((drm_format_info_block_width(format, 0) > 1) ||
1183		    (drm_format_info_block_height(format, 0) > 1))
1184			return -EINVAL;
1185		break;
1186	}
1187
1188	/*
1189	 * Changes struct fb_var_screeninfo are currently not pushed back
1190	 * to KMS, hence fail if different settings are requested.
1191	 */
1192	bpp = drm_format_info_bpp(format, 0);
1193	if (var->bits_per_pixel > bpp ||
1194	    var->xres > fb->width || var->yres > fb->height ||
1195	    var->xres_virtual > fb->width || var->yres_virtual > fb->height) {
1196		drm_dbg_kms(dev, "fb requested width/height/bpp can't fit in current fb "
1197			  "request %dx%d-%d (virtual %dx%d) > %dx%d-%d\n",
1198			  var->xres, var->yres, var->bits_per_pixel,
1199			  var->xres_virtual, var->yres_virtual,
1200			  fb->width, fb->height, bpp);
1201		return -EINVAL;
1202	}
1203
1204	__fill_var(var, info, fb);
1205
1206	/*
1207	 * fb_pan_display() validates this, but fb_set_par() doesn't and just
1208	 * falls over. Note that __fill_var above adjusts y/res_virtual.
1209	 */
1210	if (var->yoffset > var->yres_virtual - var->yres ||
1211	    var->xoffset > var->xres_virtual - var->xres)
1212		return -EINVAL;
1213
1214	/* We neither support grayscale nor FOURCC (also stored in here). */
1215	if (var->grayscale > 0)
1216		return -EINVAL;
1217
1218	if (var->nonstd)
1219		return -EINVAL;
1220
1221	/*
1222	 * Workaround for SDL 1.2, which is known to be setting all pixel format
1223	 * fields values to zero in some cases. We treat this situation as a
1224	 * kind of "use some reasonable autodetected values".
1225	 */
1226	if (!var->red.offset     && !var->green.offset    &&
1227	    !var->blue.offset    && !var->transp.offset   &&
1228	    !var->red.length     && !var->green.length    &&
1229	    !var->blue.length    && !var->transp.length   &&
1230	    !var->red.msb_right  && !var->green.msb_right &&
1231	    !var->blue.msb_right && !var->transp.msb_right) {
1232		drm_fb_helper_fill_pixel_fmt(var, format);
1233	}
1234
1235	/*
1236	 * drm fbdev emulation doesn't support changing the pixel format at all,
1237	 * so reject all pixel format changing requests.
1238	 */
1239	if (!drm_fb_pixel_format_equal(var, &info->var)) {
1240		drm_dbg_kms(dev, "fbdev emulation doesn't support changing the pixel format\n");
1241		return -EINVAL;
1242	}
1243
1244	return 0;
1245}
1246EXPORT_SYMBOL(drm_fb_helper_check_var);
1247
1248/**
1249 * drm_fb_helper_set_par - implementation for &fb_ops.fb_set_par
1250 * @info: fbdev registered by the helper
1251 *
1252 * This will let fbcon do the mode init and is called at initialization time by
1253 * the fbdev core when registering the driver, and later on through the hotplug
1254 * callback.
1255 */
1256int drm_fb_helper_set_par(struct fb_info *info)
1257{
1258	struct drm_fb_helper *fb_helper = info->par;
1259	struct fb_var_screeninfo *var = &info->var;
1260	bool force;
1261
1262	if (oops_in_progress)
1263		return -EBUSY;
1264
1265	/*
1266	 * Normally we want to make sure that a kms master takes precedence over
1267	 * fbdev, to avoid fbdev flickering and occasionally stealing the
1268	 * display status. But Xorg first sets the vt back to text mode using
1269	 * the KDSET IOCTL with KD_TEXT, and only after that drops the master
1270	 * status when exiting.
1271	 *
1272	 * In the past this was caught by drm_fb_helper_restore_fbdev_mode_unlocked(),
1273	 * but on modern systems where logind always keeps a drm fd open to
1274	 * orchestrate the vt switching, this doesn't work.
1275	 *
1276	 * To not break the userspace ABI we have this special case here, which
1277	 * is only used for the above case. Everything else uses the normal
1278	 * commit function, which ensures that we never steal the display from
1279	 * an active drm master.
1280	 */
1281	force = var->activate & FB_ACTIVATE_KD_TEXT;
1282
1283	__drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper, force);
1284
1285	return 0;
1286}
1287EXPORT_SYMBOL(drm_fb_helper_set_par);
1288
1289static void pan_set(struct drm_fb_helper *fb_helper, int dx, int dy)
1290{
1291	struct drm_mode_set *mode_set;
1292
1293	mutex_lock(&fb_helper->client.modeset_mutex);
1294	drm_client_for_each_modeset(mode_set, &fb_helper->client) {
1295		mode_set->x += dx;
1296		mode_set->y += dy;
1297	}
1298	mutex_unlock(&fb_helper->client.modeset_mutex);
1299}
1300
1301static int pan_display_atomic(struct fb_var_screeninfo *var,
1302			      struct fb_info *info)
1303{
1304	struct drm_fb_helper *fb_helper = info->par;
1305	int ret, dx, dy;
1306
1307	dx = var->xoffset - info->var.xoffset;
1308	dy = var->yoffset - info->var.yoffset;
1309	pan_set(fb_helper, dx, dy);
1310
1311	ret = drm_client_modeset_commit_locked(&fb_helper->client);
1312	if (!ret) {
1313		info->var.xoffset = var->xoffset;
1314		info->var.yoffset = var->yoffset;
1315	} else
1316		pan_set(fb_helper, -dx, -dy);
1317
1318	return ret;
1319}
1320
1321static int pan_display_legacy(struct fb_var_screeninfo *var,
1322			      struct fb_info *info)
1323{
1324	struct drm_fb_helper *fb_helper = info->par;
1325	struct drm_client_dev *client = &fb_helper->client;
1326	struct drm_mode_set *modeset;
1327	int ret = 0;
1328
1329	mutex_lock(&client->modeset_mutex);
1330	drm_modeset_lock_all(fb_helper->dev);
1331	drm_client_for_each_modeset(modeset, client) {
1332		modeset->x = var->xoffset;
1333		modeset->y = var->yoffset;
1334
1335		if (modeset->num_connectors) {
1336			ret = drm_mode_set_config_internal(modeset);
1337			if (!ret) {
1338				info->var.xoffset = var->xoffset;
1339				info->var.yoffset = var->yoffset;
1340			}
1341		}
1342	}
1343	drm_modeset_unlock_all(fb_helper->dev);
1344	mutex_unlock(&client->modeset_mutex);
1345
1346	return ret;
1347}
1348
1349/**
1350 * drm_fb_helper_pan_display - implementation for &fb_ops.fb_pan_display
1351 * @var: updated screen information
1352 * @info: fbdev registered by the helper
1353 */
1354int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
1355			      struct fb_info *info)
1356{
1357	struct drm_fb_helper *fb_helper = info->par;
1358	struct drm_device *dev = fb_helper->dev;
1359	int ret;
1360
1361	if (oops_in_progress)
1362		return -EBUSY;
1363
1364	mutex_lock(&fb_helper->lock);
1365	if (!drm_master_internal_acquire(dev)) {
1366		ret = -EBUSY;
1367		goto unlock;
1368	}
1369
1370	if (drm_drv_uses_atomic_modeset(dev))
1371		ret = pan_display_atomic(var, info);
1372	else
1373		ret = pan_display_legacy(var, info);
1374
1375	drm_master_internal_release(dev);
1376unlock:
1377	mutex_unlock(&fb_helper->lock);
1378
1379	return ret;
1380}
1381EXPORT_SYMBOL(drm_fb_helper_pan_display);
1382
1383static uint32_t drm_fb_helper_find_format(struct drm_fb_helper *fb_helper, const uint32_t *formats,
1384					  size_t format_count, unsigned int color_mode)
1385{
1386	struct drm_device *dev = fb_helper->dev;
1387	uint32_t format;
1388	size_t i;
1389
1390	format = drm_driver_color_mode_format(dev, color_mode);
1391	if (!format) {
1392		drm_info(dev, "unsupported color mode of %d\n", color_mode);
1393		return DRM_FORMAT_INVALID;
1394	}
1395
1396	for (i = 0; i < format_count; ++i) {
1397		if (formats[i] == format)
1398			return format;
1399	}
1400	drm_warn(dev, "format %p4cc not supported\n", &format);
1401
1402	return DRM_FORMAT_INVALID;
1403}
1404
1405static int __drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper,
1406				      struct drm_fb_helper_surface_size *sizes)
1407{
1408	struct drm_client_dev *client = &fb_helper->client;
1409	struct drm_device *dev = fb_helper->dev;
1410	int crtc_count = 0;
1411	struct drm_connector_list_iter conn_iter;
1412	struct drm_connector *connector;
1413	struct drm_mode_set *mode_set;
1414	uint32_t surface_format = DRM_FORMAT_INVALID;
1415	const struct drm_format_info *info;
1416
1417	memset(sizes, 0, sizeof(*sizes));
1418	sizes->fb_width = (u32)-1;
1419	sizes->fb_height = (u32)-1;
1420
1421	drm_client_for_each_modeset(mode_set, client) {
1422		struct drm_crtc *crtc = mode_set->crtc;
1423		struct drm_plane *plane = crtc->primary;
1424
1425		drm_dbg_kms(dev, "test CRTC %u primary plane\n", drm_crtc_index(crtc));
1426
1427		drm_connector_list_iter_begin(fb_helper->dev, &conn_iter);
1428		drm_client_for_each_connector_iter(connector, &conn_iter) {
1429			struct drm_cmdline_mode *cmdline_mode = &connector->cmdline_mode;
1430
1431			if (!cmdline_mode->bpp_specified)
1432				continue;
1433
1434			surface_format = drm_fb_helper_find_format(fb_helper,
1435								   plane->format_types,
1436								   plane->format_count,
1437								   cmdline_mode->bpp);
1438			if (surface_format != DRM_FORMAT_INVALID)
1439				break; /* found supported format */
1440		}
1441		drm_connector_list_iter_end(&conn_iter);
1442
1443		if (surface_format != DRM_FORMAT_INVALID)
1444			break; /* found supported format */
1445
1446		/* try preferred color mode */
1447		surface_format = drm_fb_helper_find_format(fb_helper,
1448							   plane->format_types,
1449							   plane->format_count,
1450							   fb_helper->preferred_bpp);
1451		if (surface_format != DRM_FORMAT_INVALID)
1452			break; /* found supported format */
1453	}
1454
1455	if (surface_format == DRM_FORMAT_INVALID) {
1456		/*
1457		 * If none of the given color modes works, fall back
1458		 * to XRGB8888. Drivers are expected to provide this
1459		 * format for compatibility with legacy applications.
1460		 */
1461		drm_warn(dev, "No compatible format found\n");
1462		surface_format = drm_driver_legacy_fb_format(dev, 32, 24);
1463	}
1464
1465	info = drm_format_info(surface_format);
1466	sizes->surface_bpp = drm_format_info_bpp(info, 0);
1467	sizes->surface_depth = info->depth;
1468
1469	/* first up get a count of crtcs now in use and new min/maxes width/heights */
1470	crtc_count = 0;
1471	drm_client_for_each_modeset(mode_set, client) {
1472		struct drm_display_mode *desired_mode;
1473		int x, y, j;
1474		/* in case of tile group, are we the last tile vert or horiz?
1475		 * If no tile group you are always the last one both vertically
1476		 * and horizontally
1477		 */
1478		bool lastv = true, lasth = true;
1479
1480		desired_mode = mode_set->mode;
1481
1482		if (!desired_mode)
1483			continue;
1484
1485		crtc_count++;
1486
1487		x = mode_set->x;
1488		y = mode_set->y;
1489
1490		sizes->surface_width  =
1491			max_t(u32, desired_mode->hdisplay + x, sizes->surface_width);
1492		sizes->surface_height =
1493			max_t(u32, desired_mode->vdisplay + y, sizes->surface_height);
1494
1495		for (j = 0; j < mode_set->num_connectors; j++) {
1496			struct drm_connector *connector = mode_set->connectors[j];
1497
1498			if (connector->has_tile &&
1499			    desired_mode->hdisplay == connector->tile_h_size &&
1500			    desired_mode->vdisplay == connector->tile_v_size) {
1501				lasth = (connector->tile_h_loc == (connector->num_h_tile - 1));
1502				lastv = (connector->tile_v_loc == (connector->num_v_tile - 1));
1503				/* cloning to multiple tiles is just crazy-talk, so: */
1504				break;
1505			}
1506		}
1507
1508		if (lasth)
1509			sizes->fb_width  = min_t(u32, desired_mode->hdisplay + x, sizes->fb_width);
1510		if (lastv)
1511			sizes->fb_height = min_t(u32, desired_mode->vdisplay + y, sizes->fb_height);
1512	}
1513
1514	if (crtc_count == 0 || sizes->fb_width == -1 || sizes->fb_height == -1) {
1515		drm_info(dev, "Cannot find any crtc or sizes\n");
1516		return -EAGAIN;
1517	}
1518
1519	return 0;
1520}
1521
1522static int drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper,
1523				    struct drm_fb_helper_surface_size *sizes)
1524{
1525	struct drm_client_dev *client = &fb_helper->client;
1526	struct drm_device *dev = fb_helper->dev;
1527	struct drm_mode_config *config = &dev->mode_config;
1528	int ret;
1529
1530	mutex_lock(&client->modeset_mutex);
1531	ret = __drm_fb_helper_find_sizes(fb_helper, sizes);
1532	mutex_unlock(&client->modeset_mutex);
1533
1534	if (ret)
1535		return ret;
1536
1537	/* Handle our overallocation */
1538	sizes->surface_height *= drm_fbdev_overalloc;
1539	sizes->surface_height /= 100;
1540	if (sizes->surface_height > config->max_height) {
1541		drm_dbg_kms(dev, "Fbdev over-allocation too large; clamping height to %d\n",
1542			    config->max_height);
1543		sizes->surface_height = config->max_height;
1544	}
1545
1546	return 0;
1547}
1548
1549/*
1550 * Allocates the backing storage and sets up the fbdev info structure through
1551 * the ->fbdev_probe callback.
1552 */
1553static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper)
1554{
1555	struct drm_client_dev *client = &fb_helper->client;
1556	struct drm_device *dev = fb_helper->dev;
1557	struct drm_fb_helper_surface_size sizes;
1558	int ret;
1559
1560	if (drm_WARN_ON(dev, !dev->driver->fbdev_probe))
1561		return -EINVAL;
1562
1563	ret = drm_fb_helper_find_sizes(fb_helper, &sizes);
1564	if (ret) {
1565		/* First time: disable all crtc's.. */
1566		if (!fb_helper->deferred_setup)
1567			drm_client_modeset_commit(client);
1568		return ret;
1569	}
1570
1571	/* push down into drivers */
1572	ret = dev->driver->fbdev_probe(fb_helper, &sizes);
1573	if (ret < 0)
1574		return ret;
1575
1576	strcpy(fb_helper->fb->comm, "[fbcon]");
1577
1578	return 0;
1579}
1580
1581static void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
1582				   bool is_color_indexed)
1583{
1584	info->fix.type = FB_TYPE_PACKED_PIXELS;
1585	info->fix.visual = is_color_indexed ? FB_VISUAL_PSEUDOCOLOR
1586					    : FB_VISUAL_TRUECOLOR;
1587	info->fix.mmio_start = 0;
1588	info->fix.mmio_len = 0;
1589	info->fix.type_aux = 0;
1590	info->fix.xpanstep = 1; /* doing it in hw */
1591	info->fix.ypanstep = 1; /* doing it in hw */
1592	info->fix.ywrapstep = 0;
1593	info->fix.accel = FB_ACCEL_NONE;
1594
1595	info->fix.line_length = pitch;
1596}
1597
1598static void drm_fb_helper_fill_var(struct fb_info *info,
1599				   struct drm_fb_helper *fb_helper,
1600				   uint32_t fb_width, uint32_t fb_height)
1601{
1602	struct drm_framebuffer *fb = fb_helper->fb;
1603	const struct drm_format_info *format = fb->format;
1604
1605	switch (format->format) {
1606	case DRM_FORMAT_C1:
1607	case DRM_FORMAT_C2:
1608	case DRM_FORMAT_C4:
1609		/* supported format with sub-byte pixels */
1610		break;
1611
1612	default:
1613		WARN_ON((drm_format_info_block_width(format, 0) > 1) ||
1614			(drm_format_info_block_height(format, 0) > 1));
1615		break;
1616	}
1617
1618	info->pseudo_palette = fb_helper->pseudo_palette;
1619	info->var.xoffset = 0;
1620	info->var.yoffset = 0;
1621	__fill_var(&info->var, info, fb);
1622	info->var.activate = FB_ACTIVATE_NOW;
1623
1624	drm_fb_helper_fill_pixel_fmt(&info->var, format);
1625
1626	info->var.xres = fb_width;
1627	info->var.yres = fb_height;
1628}
1629
1630/**
1631 * drm_fb_helper_fill_info - initializes fbdev information
1632 * @info: fbdev instance to set up
1633 * @fb_helper: fb helper instance to use as template
1634 * @sizes: describes fbdev size and scanout surface size
1635 *
1636 * Sets up the variable and fixed fbdev metainformation from the given fb helper
1637 * instance and the drm framebuffer allocated in &drm_fb_helper.fb.
1638 *
1639 * Drivers should call this (or their equivalent setup code) from their
1640 * &drm_driver.fbdev_probe callback after having allocated the fbdev
1641 * backing storage framebuffer.
1642 */
1643void drm_fb_helper_fill_info(struct fb_info *info,
1644			     struct drm_fb_helper *fb_helper,
1645			     struct drm_fb_helper_surface_size *sizes)
1646{
1647	struct drm_framebuffer *fb = fb_helper->fb;
1648
1649	drm_fb_helper_fill_fix(info, fb->pitches[0],
1650			       fb->format->is_color_indexed);
1651	drm_fb_helper_fill_var(info, fb_helper,
1652			       sizes->fb_width, sizes->fb_height);
1653
1654	info->par = fb_helper;
1655	/*
1656	 * The DRM drivers fbdev emulation device name can be confusing if the
1657	 * driver name also has a "drm" suffix on it. Leading to names such as
1658	 * "simpledrmdrmfb" in /proc/fb. Unfortunately, it's an uAPI and can't
1659	 * be changed due user-space tools (e.g: pm-utils) matching against it.
1660	 */
1661	snprintf(info->fix.id, sizeof(info->fix.id), "%sdrmfb",
1662		 fb_helper->dev->driver->name);
1663
1664}
1665EXPORT_SYMBOL(drm_fb_helper_fill_info);
1666
1667/*
1668 * This is a continuation of drm_setup_crtcs() that sets up anything related
1669 * to the framebuffer. During initialization, drm_setup_crtcs() is called before
1670 * the framebuffer has been allocated (fb_helper->fb and fb_helper->info).
1671 * So, any setup that touches those fields needs to be done here instead of in
1672 * drm_setup_crtcs().
1673 */
1674static void drm_setup_crtcs_fb(struct drm_fb_helper *fb_helper)
1675{
1676	struct drm_client_dev *client = &fb_helper->client;
1677	struct drm_connector_list_iter conn_iter;
1678	struct fb_info *info = fb_helper->info;
1679	unsigned int rotation, sw_rotations = 0;
1680	struct drm_connector *connector;
1681	struct drm_mode_set *modeset;
1682
1683	mutex_lock(&client->modeset_mutex);
1684	drm_client_for_each_modeset(modeset, client) {
1685		if (!modeset->num_connectors)
1686			continue;
1687
1688		modeset->fb = fb_helper->fb;
1689
1690		if (drm_client_rotation(modeset, &rotation))
1691			/* Rotating in hardware, fbcon should not rotate */
1692			sw_rotations |= DRM_MODE_ROTATE_0;
1693		else
1694			sw_rotations |= rotation;
1695	}
1696	mutex_unlock(&client->modeset_mutex);
1697
1698	drm_connector_list_iter_begin(fb_helper->dev, &conn_iter);
1699	drm_client_for_each_connector_iter(connector, &conn_iter) {
1700
1701		/* use first connected connector for the physical dimensions */
1702		if (connector->status == connector_status_connected) {
1703			info->var.width = connector->display_info.width_mm;
1704			info->var.height = connector->display_info.height_mm;
1705			break;
1706		}
1707	}
1708	drm_connector_list_iter_end(&conn_iter);
1709
1710	switch (sw_rotations) {
1711	case DRM_MODE_ROTATE_0:
1712		info->fbcon_rotate_hint = FB_ROTATE_UR;
1713		break;
1714	case DRM_MODE_ROTATE_90:
1715		info->fbcon_rotate_hint = FB_ROTATE_CCW;
1716		break;
1717	case DRM_MODE_ROTATE_180:
1718		info->fbcon_rotate_hint = FB_ROTATE_UD;
1719		break;
1720	case DRM_MODE_ROTATE_270:
1721		info->fbcon_rotate_hint = FB_ROTATE_CW;
1722		break;
1723	default:
1724		/*
1725		 * Multiple bits are set / multiple rotations requested
1726		 * fbcon cannot handle separate rotation settings per
1727		 * output, so fallback to unrotated.
1728		 */
1729		info->fbcon_rotate_hint = FB_ROTATE_UR;
1730	}
1731}
1732
1733/* Note: Drops fb_helper->lock before returning. */
1734static int
1735__drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper)
1736{
1737	struct drm_device *dev = fb_helper->dev;
1738	struct fb_info *info;
1739	unsigned int width, height;
1740	int ret;
1741
1742	width = dev->mode_config.max_width;
1743	height = dev->mode_config.max_height;
1744
1745	drm_client_modeset_probe(&fb_helper->client, width, height);
1746
1747	info = drm_fb_helper_alloc_info(fb_helper);
1748	if (IS_ERR(info))
1749		return PTR_ERR(info);
1750
1751	ret = drm_fb_helper_single_fb_probe(fb_helper);
1752	if (ret < 0) {
1753		if (ret == -EAGAIN) {
1754			fb_helper->deferred_setup = true;
1755			ret = 0;
1756		}
1757		mutex_unlock(&fb_helper->lock);
1758
1759		goto err_drm_fb_helper_release_info;
1760	}
1761	drm_setup_crtcs_fb(fb_helper);
1762
1763	fb_helper->deferred_setup = false;
1764
1765	info->var.pixclock = 0;
1766
1767	/* Need to drop locks to avoid recursive deadlock in
1768	 * register_framebuffer. This is ok because the only thing left to do is
1769	 * register the fbdev emulation instance in kernel_fb_helper_list. */
1770	mutex_unlock(&fb_helper->lock);
1771
1772	ret = register_framebuffer(info);
1773	if (ret < 0)
1774		return ret;
1775
1776	drm_info(dev, "fb%d: %s frame buffer device\n",
1777		 info->node, info->fix.id);
1778
1779	mutex_lock(&kernel_fb_helper_lock);
1780	list_add(&fb_helper->kernel_fb_list, &kernel_fb_helper_list);
1781	mutex_unlock(&kernel_fb_helper_lock);
1782
1783	return 0;
1784
1785err_drm_fb_helper_release_info:
1786	drm_fb_helper_release_info(fb_helper);
1787	return ret;
1788}
1789
1790/**
1791 * drm_fb_helper_initial_config - setup a sane initial connector configuration
1792 * @fb_helper: fb_helper device struct
1793 *
1794 * Scans the CRTCs and connectors and tries to put together an initial setup.
1795 * At the moment, this is a cloned configuration across all heads with
1796 * a new framebuffer object as the backing store.
1797 *
1798 * Note that this also registers the fbdev and so allows userspace to call into
1799 * the driver through the fbdev interfaces.
1800 *
1801 * This function will call down into the &drm_driver.fbdev_probe callback
1802 * to let the driver allocate and initialize the fbdev info structure and the
1803 * drm framebuffer used to back the fbdev. drm_fb_helper_fill_info() is provided
1804 * as a helper to setup simple default values for the fbdev info structure.
1805 *
1806 * HANG DEBUGGING:
1807 *
1808 * When you have fbcon support built-in or already loaded, this function will do
1809 * a full modeset to setup the fbdev console. Due to locking misdesign in the
1810 * VT/fbdev subsystem that entire modeset sequence has to be done while holding
1811 * console_lock. Until console_unlock is called no dmesg lines will be sent out
1812 * to consoles, not even serial console. This means when your driver crashes,
1813 * you will see absolutely nothing else but a system stuck in this function,
1814 * with no further output. Any kind of printk() you place within your own driver
1815 * or in the drm core modeset code will also never show up.
1816 *
1817 * Standard debug practice is to run the fbcon setup without taking the
1818 * console_lock as a hack, to be able to see backtraces and crashes on the
1819 * serial line. This can be done by setting the fb.lockless_register_fb=1 kernel
1820 * cmdline option.
1821 *
1822 * The other option is to just disable fbdev emulation since very likely the
1823 * first modeset from userspace will crash in the same way, and is even easier
1824 * to debug. This can be done by setting the drm_kms_helper.fbdev_emulation=0
1825 * kernel cmdline option.
1826 *
1827 * RETURNS:
1828 * Zero if everything went ok, nonzero otherwise.
1829 */
1830int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper)
1831{
1832	int ret;
1833
1834	if (!drm_fbdev_emulation)
1835		return 0;
1836
1837	mutex_lock(&fb_helper->lock);
1838	ret = __drm_fb_helper_initial_config_and_unlock(fb_helper);
1839
1840	return ret;
1841}
1842EXPORT_SYMBOL(drm_fb_helper_initial_config);
1843
1844/**
1845 * drm_fb_helper_hotplug_event - respond to a hotplug notification by
1846 *                               probing all the outputs attached to the fb
1847 * @fb_helper: driver-allocated fbdev helper, can be NULL
1848 *
1849 * Scan the connectors attached to the fb_helper and try to put together a
1850 * setup after notification of a change in output configuration.
1851 *
1852 * Called at runtime, takes the mode config locks to be able to check/change the
1853 * modeset configuration. Must be run from process context (which usually means
1854 * either the output polling work or a work item launched from the driver's
1855 * hotplug interrupt).
1856 *
1857 * Note that drivers may call this even before calling
1858 * drm_fb_helper_initial_config but only after drm_fb_helper_init. This allows
1859 * for a race-free fbcon setup and will make sure that the fbdev emulation will
1860 * not miss any hotplug events.
1861 *
1862 * RETURNS:
1863 * 0 on success and a non-zero error code otherwise.
1864 */
1865int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
1866{
1867	int err = 0;
1868
1869	if (!drm_fbdev_emulation || !fb_helper)
1870		return 0;
1871
1872	mutex_lock(&fb_helper->lock);
1873	if (fb_helper->deferred_setup) {
1874		err = __drm_fb_helper_initial_config_and_unlock(fb_helper);
1875		return err;
1876	}
1877
1878	if (!fb_helper->fb || !drm_master_internal_acquire(fb_helper->dev)) {
1879		fb_helper->delayed_hotplug = true;
1880		mutex_unlock(&fb_helper->lock);
1881		return err;
1882	}
1883
1884	drm_master_internal_release(fb_helper->dev);
1885
1886	drm_dbg_kms(fb_helper->dev, "\n");
1887
1888	drm_client_modeset_probe(&fb_helper->client, fb_helper->fb->width, fb_helper->fb->height);
1889	drm_setup_crtcs_fb(fb_helper);
1890	mutex_unlock(&fb_helper->lock);
1891
1892	drm_fb_helper_set_par(fb_helper->info);
1893
1894	return 0;
1895}
1896EXPORT_SYMBOL(drm_fb_helper_hotplug_event);