xref: /linux/drivers/gpu/drm/drm_fb_helper.c (revision 3d0fe49454652117522f60bfbefb978ba0e5300b)
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/pci.h>
34 #include <linux/sysrq.h>
35 #include <linux/vga_switcheroo.h>
36 
37 #include <drm/drm_atomic.h>
38 #include <drm/drm_drv.h>
39 #include <drm/drm_fb_helper.h>
40 #include <drm/drm_fourcc.h>
41 #include <drm/drm_framebuffer.h>
42 #include <drm/drm_modeset_helper_vtables.h>
43 #include <drm/drm_print.h>
44 #include <drm/drm_vblank.h>
45 
46 #include "drm_internal.h"
47 
48 static bool drm_fbdev_emulation = true;
49 module_param_named(fbdev_emulation, drm_fbdev_emulation, bool, 0600);
50 MODULE_PARM_DESC(fbdev_emulation,
51 		 "Enable legacy fbdev emulation [default=true]");
52 
53 static int drm_fbdev_overalloc = CONFIG_DRM_FBDEV_OVERALLOC;
54 module_param(drm_fbdev_overalloc, int, 0444);
55 MODULE_PARM_DESC(drm_fbdev_overalloc,
56 		 "Overallocation of the fbdev buffer (%) [default="
57 		 __MODULE_STRING(CONFIG_DRM_FBDEV_OVERALLOC) "]");
58 
59 /*
60  * In order to keep user-space compatibility, we want in certain use-cases
61  * to keep leaking the fbdev physical address to the user-space program
62  * handling the fbdev buffer.
63  *
64  * This is a bad habit, essentially kept to support closed-source OpenGL
65  * drivers that should really be moved into open-source upstream projects
66  * instead of using legacy physical addresses in user space to communicate
67  * with other out-of-tree kernel modules.
68  *
69  * This module_param *should* be removed as soon as possible and be
70  * considered as a broken and legacy behaviour from a modern fbdev device.
71  */
72 static bool drm_leak_fbdev_smem;
73 #if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM)
74 module_param_unsafe(drm_leak_fbdev_smem, bool, 0600);
75 MODULE_PARM_DESC(drm_leak_fbdev_smem,
76 		 "Allow unsafe leaking fbdev physical smem address [default=false]");
77 #endif
78 
79 static LIST_HEAD(kernel_fb_helper_list);
80 static DEFINE_MUTEX(kernel_fb_helper_lock);
81 
82 /**
83  * DOC: fbdev helpers
84  *
85  * The fb helper functions are useful to provide an fbdev on top of a drm kernel
86  * mode setting driver. They can be used mostly independently from the crtc
87  * helper functions used by many drivers to implement the kernel mode setting
88  * interfaces.
89  *
90  * Drivers that support a dumb buffer with a virtual address and mmap support,
91  * should try out the generic fbdev emulation using drm_fbdev_generic_setup().
92  * It will automatically set up deferred I/O if the driver requires a shadow
93  * buffer.
94  *
95  * Existing fbdev implementations should restore the fbdev console by using
96  * drm_fb_helper_lastclose() as their &drm_driver.lastclose callback.
97  * They should also notify the fb helper code from updates to the output
98  * configuration by using drm_fb_helper_output_poll_changed() as their
99  * &drm_mode_config_funcs.output_poll_changed callback. New implementations
100  * of fbdev should be build on top of struct &drm_client_funcs, which handles
101  * this automatically. Setting the old callbacks should be avoided.
102  *
103  * For suspend/resume consider using drm_mode_config_helper_suspend() and
104  * drm_mode_config_helper_resume() which takes care of fbdev as well.
105  *
106  * All other functions exported by the fb helper library can be used to
107  * implement the fbdev driver interface by the driver.
108  *
109  * It is possible, though perhaps somewhat tricky, to implement race-free
110  * hotplug detection using the fbdev helpers. The drm_fb_helper_prepare()
111  * helper must be called first to initialize the minimum required to make
112  * hotplug detection work. Drivers also need to make sure to properly set up
113  * the &drm_mode_config.funcs member. After calling drm_kms_helper_poll_init()
114  * it is safe to enable interrupts and start processing hotplug events. At the
115  * same time, drivers should initialize all modeset objects such as CRTCs,
116  * encoders and connectors. To finish up the fbdev helper initialization, the
117  * drm_fb_helper_init() function is called. To probe for all attached displays
118  * and set up an initial configuration using the detected hardware, drivers
119  * should call drm_fb_helper_initial_config().
120  *
121  * If &drm_framebuffer_funcs.dirty is set, the
122  * drm_fb_helper_{cfb,sys}_{write,fillrect,copyarea,imageblit} functions will
123  * accumulate changes and schedule &drm_fb_helper.dirty_work to run right
124  * away. This worker then calls the dirty() function ensuring that it will
125  * always run in process context since the fb_*() function could be running in
126  * atomic context. If drm_fb_helper_deferred_io() is used as the deferred_io
127  * callback it will also schedule dirty_work with the damage collected from the
128  * mmap page writes.
129  *
130  * Deferred I/O is not compatible with SHMEM. Such drivers should request an
131  * fbdev shadow buffer and call drm_fbdev_generic_setup() instead.
132  */
133 
134 static void drm_fb_helper_restore_lut_atomic(struct drm_crtc *crtc)
135 {
136 	uint16_t *r_base, *g_base, *b_base;
137 
138 	if (crtc->funcs->gamma_set == NULL)
139 		return;
140 
141 	r_base = crtc->gamma_store;
142 	g_base = r_base + crtc->gamma_size;
143 	b_base = g_base + crtc->gamma_size;
144 
145 	crtc->funcs->gamma_set(crtc, r_base, g_base, b_base,
146 			       crtc->gamma_size, NULL);
147 }
148 
149 /**
150  * drm_fb_helper_debug_enter - implementation for &fb_ops.fb_debug_enter
151  * @info: fbdev registered by the helper
152  */
153 int drm_fb_helper_debug_enter(struct fb_info *info)
154 {
155 	struct drm_fb_helper *helper = info->par;
156 	const struct drm_crtc_helper_funcs *funcs;
157 	struct drm_mode_set *mode_set;
158 
159 	list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
160 		mutex_lock(&helper->client.modeset_mutex);
161 		drm_client_for_each_modeset(mode_set, &helper->client) {
162 			if (!mode_set->crtc->enabled)
163 				continue;
164 
165 			funcs =	mode_set->crtc->helper_private;
166 			if (funcs->mode_set_base_atomic == NULL)
167 				continue;
168 
169 			if (drm_drv_uses_atomic_modeset(mode_set->crtc->dev))
170 				continue;
171 
172 			funcs->mode_set_base_atomic(mode_set->crtc,
173 						    mode_set->fb,
174 						    mode_set->x,
175 						    mode_set->y,
176 						    ENTER_ATOMIC_MODE_SET);
177 		}
178 		mutex_unlock(&helper->client.modeset_mutex);
179 	}
180 
181 	return 0;
182 }
183 EXPORT_SYMBOL(drm_fb_helper_debug_enter);
184 
185 /**
186  * drm_fb_helper_debug_leave - implementation for &fb_ops.fb_debug_leave
187  * @info: fbdev registered by the helper
188  */
189 int drm_fb_helper_debug_leave(struct fb_info *info)
190 {
191 	struct drm_fb_helper *helper = info->par;
192 	struct drm_client_dev *client = &helper->client;
193 	struct drm_device *dev = helper->dev;
194 	struct drm_crtc *crtc;
195 	const struct drm_crtc_helper_funcs *funcs;
196 	struct drm_mode_set *mode_set;
197 	struct drm_framebuffer *fb;
198 
199 	mutex_lock(&client->modeset_mutex);
200 	drm_client_for_each_modeset(mode_set, client) {
201 		crtc = mode_set->crtc;
202 		if (drm_drv_uses_atomic_modeset(crtc->dev))
203 			continue;
204 
205 		funcs = crtc->helper_private;
206 		fb = crtc->primary->fb;
207 
208 		if (!crtc->enabled)
209 			continue;
210 
211 		if (!fb) {
212 			drm_err(dev, "no fb to restore?\n");
213 			continue;
214 		}
215 
216 		if (funcs->mode_set_base_atomic == NULL)
217 			continue;
218 
219 		drm_fb_helper_restore_lut_atomic(mode_set->crtc);
220 		funcs->mode_set_base_atomic(mode_set->crtc, fb, crtc->x,
221 					    crtc->y, LEAVE_ATOMIC_MODE_SET);
222 	}
223 	mutex_unlock(&client->modeset_mutex);
224 
225 	return 0;
226 }
227 EXPORT_SYMBOL(drm_fb_helper_debug_leave);
228 
229 static int
230 __drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper,
231 					    bool force)
232 {
233 	bool do_delayed;
234 	int ret;
235 
236 	if (!drm_fbdev_emulation || !fb_helper)
237 		return -ENODEV;
238 
239 	if (READ_ONCE(fb_helper->deferred_setup))
240 		return 0;
241 
242 	mutex_lock(&fb_helper->lock);
243 	if (force) {
244 		/*
245 		 * Yes this is the _locked version which expects the master lock
246 		 * to be held. But for forced restores we're intentionally
247 		 * racing here, see drm_fb_helper_set_par().
248 		 */
249 		ret = drm_client_modeset_commit_locked(&fb_helper->client);
250 	} else {
251 		ret = drm_client_modeset_commit(&fb_helper->client);
252 	}
253 
254 	do_delayed = fb_helper->delayed_hotplug;
255 	if (do_delayed)
256 		fb_helper->delayed_hotplug = false;
257 	mutex_unlock(&fb_helper->lock);
258 
259 	if (do_delayed)
260 		drm_fb_helper_hotplug_event(fb_helper);
261 
262 	return ret;
263 }
264 
265 /**
266  * drm_fb_helper_restore_fbdev_mode_unlocked - restore fbdev configuration
267  * @fb_helper: driver-allocated fbdev helper, can be NULL
268  *
269  * This should be called from driver's drm &drm_driver.lastclose callback
270  * when implementing an fbcon on top of kms using this helper. This ensures that
271  * the user isn't greeted with a black screen when e.g. X dies.
272  *
273  * RETURNS:
274  * Zero if everything went ok, negative error code otherwise.
275  */
276 int drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
277 {
278 	return __drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper, false);
279 }
280 EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode_unlocked);
281 
282 #ifdef CONFIG_MAGIC_SYSRQ
283 /* emergency restore, don't bother with error reporting */
284 static void drm_fb_helper_restore_work_fn(struct work_struct *ignored)
285 {
286 	struct drm_fb_helper *helper;
287 
288 	mutex_lock(&kernel_fb_helper_lock);
289 	list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
290 		struct drm_device *dev = helper->dev;
291 
292 		if (dev->switch_power_state == DRM_SWITCH_POWER_OFF)
293 			continue;
294 
295 		mutex_lock(&helper->lock);
296 		drm_client_modeset_commit_locked(&helper->client);
297 		mutex_unlock(&helper->lock);
298 	}
299 	mutex_unlock(&kernel_fb_helper_lock);
300 }
301 
302 static DECLARE_WORK(drm_fb_helper_restore_work, drm_fb_helper_restore_work_fn);
303 
304 static void drm_fb_helper_sysrq(u8 dummy1)
305 {
306 	schedule_work(&drm_fb_helper_restore_work);
307 }
308 
309 static const struct sysrq_key_op sysrq_drm_fb_helper_restore_op = {
310 	.handler = drm_fb_helper_sysrq,
311 	.help_msg = "force-fb(v)",
312 	.action_msg = "Restore framebuffer console",
313 };
314 #else
315 static const struct sysrq_key_op sysrq_drm_fb_helper_restore_op = { };
316 #endif
317 
318 static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode)
319 {
320 	struct drm_fb_helper *fb_helper = info->par;
321 
322 	mutex_lock(&fb_helper->lock);
323 	drm_client_modeset_dpms(&fb_helper->client, dpms_mode);
324 	mutex_unlock(&fb_helper->lock);
325 }
326 
327 /**
328  * drm_fb_helper_blank - implementation for &fb_ops.fb_blank
329  * @blank: desired blanking state
330  * @info: fbdev registered by the helper
331  */
332 int drm_fb_helper_blank(int blank, struct fb_info *info)
333 {
334 	if (oops_in_progress)
335 		return -EBUSY;
336 
337 	switch (blank) {
338 	/* Display: On; HSync: On, VSync: On */
339 	case FB_BLANK_UNBLANK:
340 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_ON);
341 		break;
342 	/* Display: Off; HSync: On, VSync: On */
343 	case FB_BLANK_NORMAL:
344 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
345 		break;
346 	/* Display: Off; HSync: Off, VSync: On */
347 	case FB_BLANK_HSYNC_SUSPEND:
348 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
349 		break;
350 	/* Display: Off; HSync: On, VSync: Off */
351 	case FB_BLANK_VSYNC_SUSPEND:
352 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_SUSPEND);
353 		break;
354 	/* Display: Off; HSync: Off, VSync: Off */
355 	case FB_BLANK_POWERDOWN:
356 		drm_fb_helper_dpms(info, DRM_MODE_DPMS_OFF);
357 		break;
358 	}
359 	return 0;
360 }
361 EXPORT_SYMBOL(drm_fb_helper_blank);
362 
363 static void drm_fb_helper_resume_worker(struct work_struct *work)
364 {
365 	struct drm_fb_helper *helper = container_of(work, struct drm_fb_helper,
366 						    resume_work);
367 
368 	console_lock();
369 	fb_set_suspend(helper->info, 0);
370 	console_unlock();
371 }
372 
373 static void drm_fb_helper_fb_dirty(struct drm_fb_helper *helper)
374 {
375 	struct drm_device *dev = helper->dev;
376 	struct drm_clip_rect *clip = &helper->damage_clip;
377 	struct drm_clip_rect clip_copy;
378 	unsigned long flags;
379 	int ret;
380 
381 	if (drm_WARN_ON_ONCE(dev, !helper->funcs->fb_dirty))
382 		return;
383 
384 	spin_lock_irqsave(&helper->damage_lock, flags);
385 	clip_copy = *clip;
386 	clip->x1 = clip->y1 = ~0;
387 	clip->x2 = clip->y2 = 0;
388 	spin_unlock_irqrestore(&helper->damage_lock, flags);
389 
390 	ret = helper->funcs->fb_dirty(helper, &clip_copy);
391 	if (ret)
392 		goto err;
393 
394 	return;
395 
396 err:
397 	/*
398 	 * Restore damage clip rectangle on errors. The next run
399 	 * of the damage worker will perform the update.
400 	 */
401 	spin_lock_irqsave(&helper->damage_lock, flags);
402 	clip->x1 = min_t(u32, clip->x1, clip_copy.x1);
403 	clip->y1 = min_t(u32, clip->y1, clip_copy.y1);
404 	clip->x2 = max_t(u32, clip->x2, clip_copy.x2);
405 	clip->y2 = max_t(u32, clip->y2, clip_copy.y2);
406 	spin_unlock_irqrestore(&helper->damage_lock, flags);
407 }
408 
409 static void drm_fb_helper_damage_work(struct work_struct *work)
410 {
411 	struct drm_fb_helper *helper = container_of(work, struct drm_fb_helper, damage_work);
412 
413 	drm_fb_helper_fb_dirty(helper);
414 }
415 
416 /**
417  * drm_fb_helper_prepare - setup a drm_fb_helper structure
418  * @dev: DRM device
419  * @helper: driver-allocated fbdev helper structure to set up
420  * @preferred_bpp: Preferred bits per pixel for the device.
421  * @funcs: pointer to structure of functions associate with this helper
422  *
423  * Sets up the bare minimum to make the framebuffer helper usable. This is
424  * useful to implement race-free initialization of the polling helpers.
425  */
426 void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
427 			   unsigned int preferred_bpp,
428 			   const struct drm_fb_helper_funcs *funcs)
429 {
430 	/*
431 	 * Pick a preferred bpp of 32 if no value has been given. This
432 	 * will select XRGB8888 for the framebuffer formats. All drivers
433 	 * have to support XRGB8888 for backwards compatibility with legacy
434 	 * userspace, so it's the safe choice here.
435 	 *
436 	 * TODO: Replace struct drm_mode_config.preferred_depth and this
437 	 *       bpp value with a preferred format that is given as struct
438 	 *       drm_format_info. Then derive all other values from the
439 	 *       format.
440 	 */
441 	if (!preferred_bpp)
442 		preferred_bpp = 32;
443 
444 	INIT_LIST_HEAD(&helper->kernel_fb_list);
445 	spin_lock_init(&helper->damage_lock);
446 	INIT_WORK(&helper->resume_work, drm_fb_helper_resume_worker);
447 	INIT_WORK(&helper->damage_work, drm_fb_helper_damage_work);
448 	helper->damage_clip.x1 = helper->damage_clip.y1 = ~0;
449 	mutex_init(&helper->lock);
450 	helper->funcs = funcs;
451 	helper->dev = dev;
452 	helper->preferred_bpp = preferred_bpp;
453 }
454 EXPORT_SYMBOL(drm_fb_helper_prepare);
455 
456 /**
457  * drm_fb_helper_unprepare - clean up a drm_fb_helper structure
458  * @fb_helper: driver-allocated fbdev helper structure to set up
459  *
460  * Cleans up the framebuffer helper. Inverse of drm_fb_helper_prepare().
461  */
462 void drm_fb_helper_unprepare(struct drm_fb_helper *fb_helper)
463 {
464 	mutex_destroy(&fb_helper->lock);
465 }
466 EXPORT_SYMBOL(drm_fb_helper_unprepare);
467 
468 /**
469  * drm_fb_helper_init - initialize a &struct drm_fb_helper
470  * @dev: drm device
471  * @fb_helper: driver-allocated fbdev helper structure to initialize
472  *
473  * This allocates the structures for the fbdev helper with the given limits.
474  * Note that this won't yet touch the hardware (through the driver interfaces)
475  * nor register the fbdev. This is only done in drm_fb_helper_initial_config()
476  * to allow driver writes more control over the exact init sequence.
477  *
478  * Drivers must call drm_fb_helper_prepare() before calling this function.
479  *
480  * RETURNS:
481  * Zero if everything went ok, nonzero otherwise.
482  */
483 int drm_fb_helper_init(struct drm_device *dev,
484 		       struct drm_fb_helper *fb_helper)
485 {
486 	int ret;
487 
488 	/*
489 	 * If this is not the generic fbdev client, initialize a drm_client
490 	 * without callbacks so we can use the modesets.
491 	 */
492 	if (!fb_helper->client.funcs) {
493 		ret = drm_client_init(dev, &fb_helper->client, "drm_fb_helper", NULL);
494 		if (ret)
495 			return ret;
496 	}
497 
498 	dev->fb_helper = fb_helper;
499 
500 	return 0;
501 }
502 EXPORT_SYMBOL(drm_fb_helper_init);
503 
504 /**
505  * drm_fb_helper_alloc_info - allocate fb_info and some of its members
506  * @fb_helper: driver-allocated fbdev helper
507  *
508  * A helper to alloc fb_info and the member cmap. Called by the driver
509  * within the fb_probe fb_helper callback function. Drivers do not
510  * need to release the allocated fb_info structure themselves, this is
511  * automatically done when calling drm_fb_helper_fini().
512  *
513  * RETURNS:
514  * fb_info pointer if things went okay, pointer containing error code
515  * otherwise
516  */
517 struct fb_info *drm_fb_helper_alloc_info(struct drm_fb_helper *fb_helper)
518 {
519 	struct device *dev = fb_helper->dev->dev;
520 	struct fb_info *info;
521 	int ret;
522 
523 	info = framebuffer_alloc(0, dev);
524 	if (!info)
525 		return ERR_PTR(-ENOMEM);
526 
527 	ret = fb_alloc_cmap(&info->cmap, 256, 0);
528 	if (ret)
529 		goto err_release;
530 
531 	fb_helper->info = info;
532 	info->skip_vt_switch = true;
533 
534 	return info;
535 
536 err_release:
537 	framebuffer_release(info);
538 	return ERR_PTR(ret);
539 }
540 EXPORT_SYMBOL(drm_fb_helper_alloc_info);
541 
542 /**
543  * drm_fb_helper_release_info - release fb_info and its members
544  * @fb_helper: driver-allocated fbdev helper
545  *
546  * A helper to release fb_info and the member cmap.  Drivers do not
547  * need to release the allocated fb_info structure themselves, this is
548  * automatically done when calling drm_fb_helper_fini().
549  */
550 void drm_fb_helper_release_info(struct drm_fb_helper *fb_helper)
551 {
552 	struct fb_info *info = fb_helper->info;
553 
554 	if (!info)
555 		return;
556 
557 	fb_helper->info = NULL;
558 
559 	if (info->cmap.len)
560 		fb_dealloc_cmap(&info->cmap);
561 	framebuffer_release(info);
562 }
563 EXPORT_SYMBOL(drm_fb_helper_release_info);
564 
565 /**
566  * drm_fb_helper_unregister_info - unregister fb_info framebuffer device
567  * @fb_helper: driver-allocated fbdev helper, can be NULL
568  *
569  * A wrapper around unregister_framebuffer, to release the fb_info
570  * framebuffer device. This must be called before releasing all resources for
571  * @fb_helper by calling drm_fb_helper_fini().
572  */
573 void drm_fb_helper_unregister_info(struct drm_fb_helper *fb_helper)
574 {
575 	if (fb_helper && fb_helper->info)
576 		unregister_framebuffer(fb_helper->info);
577 }
578 EXPORT_SYMBOL(drm_fb_helper_unregister_info);
579 
580 /**
581  * drm_fb_helper_fini - finialize a &struct drm_fb_helper
582  * @fb_helper: driver-allocated fbdev helper, can be NULL
583  *
584  * This cleans up all remaining resources associated with @fb_helper.
585  */
586 void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
587 {
588 	if (!fb_helper)
589 		return;
590 
591 	fb_helper->dev->fb_helper = NULL;
592 
593 	if (!drm_fbdev_emulation)
594 		return;
595 
596 	cancel_work_sync(&fb_helper->resume_work);
597 	cancel_work_sync(&fb_helper->damage_work);
598 
599 	drm_fb_helper_release_info(fb_helper);
600 
601 	mutex_lock(&kernel_fb_helper_lock);
602 	if (!list_empty(&fb_helper->kernel_fb_list)) {
603 		list_del(&fb_helper->kernel_fb_list);
604 		if (list_empty(&kernel_fb_helper_list))
605 			unregister_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
606 	}
607 	mutex_unlock(&kernel_fb_helper_lock);
608 
609 	if (!fb_helper->client.funcs)
610 		drm_client_release(&fb_helper->client);
611 }
612 EXPORT_SYMBOL(drm_fb_helper_fini);
613 
614 static void drm_fb_helper_add_damage_clip(struct drm_fb_helper *helper, u32 x, u32 y,
615 					  u32 width, u32 height)
616 {
617 	struct drm_clip_rect *clip = &helper->damage_clip;
618 	unsigned long flags;
619 
620 	spin_lock_irqsave(&helper->damage_lock, flags);
621 	clip->x1 = min_t(u32, clip->x1, x);
622 	clip->y1 = min_t(u32, clip->y1, y);
623 	clip->x2 = max_t(u32, clip->x2, x + width);
624 	clip->y2 = max_t(u32, clip->y2, y + height);
625 	spin_unlock_irqrestore(&helper->damage_lock, flags);
626 }
627 
628 static void drm_fb_helper_damage(struct drm_fb_helper *helper, u32 x, u32 y,
629 				 u32 width, u32 height)
630 {
631 	drm_fb_helper_add_damage_clip(helper, x, y, width, height);
632 
633 	schedule_work(&helper->damage_work);
634 }
635 
636 /*
637  * Convert memory region into area of scanlines and pixels per
638  * scanline. The parameters off and len must not reach beyond
639  * the end of the framebuffer.
640  */
641 static void drm_fb_helper_memory_range_to_clip(struct fb_info *info, off_t off, size_t len,
642 					       struct drm_rect *clip)
643 {
644 	u32 line_length = info->fix.line_length;
645 	u32 fb_height = info->var.yres;
646 	off_t end = off + len;
647 	u32 x1 = 0;
648 	u32 y1 = off / line_length;
649 	u32 x2 = info->var.xres;
650 	u32 y2 = DIV_ROUND_UP(end, line_length);
651 
652 	/* Don't allow any of them beyond the bottom bound of display area */
653 	if (y1 > fb_height)
654 		y1 = fb_height;
655 	if (y2 > fb_height)
656 		y2 = fb_height;
657 
658 	if ((y2 - y1) == 1) {
659 		/*
660 		 * We've only written to a single scanline. Try to reduce
661 		 * the number of horizontal pixels that need an update.
662 		 */
663 		off_t bit_off = (off % line_length) * 8;
664 		off_t bit_end = (end % line_length) * 8;
665 
666 		x1 = bit_off / info->var.bits_per_pixel;
667 		x2 = DIV_ROUND_UP(bit_end, info->var.bits_per_pixel);
668 	}
669 
670 	drm_rect_init(clip, x1, y1, x2 - x1, y2 - y1);
671 }
672 
673 /* Don't use in new code. */
674 void drm_fb_helper_damage_range(struct fb_info *info, off_t off, size_t len)
675 {
676 	struct drm_fb_helper *fb_helper = info->par;
677 	struct drm_rect damage_area;
678 
679 	drm_fb_helper_memory_range_to_clip(info, off, len, &damage_area);
680 	drm_fb_helper_damage(fb_helper, damage_area.x1, damage_area.y1,
681 			     drm_rect_width(&damage_area),
682 			     drm_rect_height(&damage_area));
683 }
684 EXPORT_SYMBOL(drm_fb_helper_damage_range);
685 
686 /* Don't use in new code. */
687 void drm_fb_helper_damage_area(struct fb_info *info, u32 x, u32 y, u32 width, u32 height)
688 {
689 	struct drm_fb_helper *fb_helper = info->par;
690 
691 	drm_fb_helper_damage(fb_helper, x, y, width, height);
692 }
693 EXPORT_SYMBOL(drm_fb_helper_damage_area);
694 
695 /**
696  * drm_fb_helper_deferred_io() - fbdev deferred_io callback function
697  * @info: fb_info struct pointer
698  * @pagereflist: list of mmap framebuffer pages that have to be flushed
699  *
700  * This function is used as the &fb_deferred_io.deferred_io
701  * callback function for flushing the fbdev mmap writes.
702  */
703 void drm_fb_helper_deferred_io(struct fb_info *info, struct list_head *pagereflist)
704 {
705 	struct drm_fb_helper *helper = info->par;
706 	unsigned long start, end, min_off, max_off, total_size;
707 	struct fb_deferred_io_pageref *pageref;
708 	struct drm_rect damage_area;
709 
710 	min_off = ULONG_MAX;
711 	max_off = 0;
712 	list_for_each_entry(pageref, pagereflist, list) {
713 		start = pageref->offset;
714 		end = start + PAGE_SIZE;
715 		min_off = min(min_off, start);
716 		max_off = max(max_off, end);
717 	}
718 
719 	/*
720 	 * As we can only track pages, we might reach beyond the end
721 	 * of the screen and account for non-existing scanlines. Hence,
722 	 * keep the covered memory area within the screen buffer.
723 	 */
724 	if (info->screen_size)
725 		total_size = info->screen_size;
726 	else
727 		total_size = info->fix.smem_len;
728 	max_off = min(max_off, total_size);
729 
730 	if (min_off < max_off) {
731 		drm_fb_helper_memory_range_to_clip(info, min_off, max_off - min_off, &damage_area);
732 		drm_fb_helper_damage(helper, damage_area.x1, damage_area.y1,
733 				     drm_rect_width(&damage_area),
734 				     drm_rect_height(&damage_area));
735 	}
736 }
737 EXPORT_SYMBOL(drm_fb_helper_deferred_io);
738 
739 /**
740  * drm_fb_helper_set_suspend - wrapper around fb_set_suspend
741  * @fb_helper: driver-allocated fbdev helper, can be NULL
742  * @suspend: whether to suspend or resume
743  *
744  * A wrapper around fb_set_suspend implemented by fbdev core.
745  * Use drm_fb_helper_set_suspend_unlocked() if you don't need to take
746  * the lock yourself
747  */
748 void drm_fb_helper_set_suspend(struct drm_fb_helper *fb_helper, bool suspend)
749 {
750 	if (fb_helper && fb_helper->info)
751 		fb_set_suspend(fb_helper->info, suspend);
752 }
753 EXPORT_SYMBOL(drm_fb_helper_set_suspend);
754 
755 /**
756  * drm_fb_helper_set_suspend_unlocked - wrapper around fb_set_suspend that also
757  *                                      takes the console lock
758  * @fb_helper: driver-allocated fbdev helper, can be NULL
759  * @suspend: whether to suspend or resume
760  *
761  * A wrapper around fb_set_suspend() that takes the console lock. If the lock
762  * isn't available on resume, a worker is tasked with waiting for the lock
763  * to become available. The console lock can be pretty contented on resume
764  * due to all the printk activity.
765  *
766  * This function can be called multiple times with the same state since
767  * &fb_info.state is checked to see if fbdev is running or not before locking.
768  *
769  * Use drm_fb_helper_set_suspend() if you need to take the lock yourself.
770  */
771 void drm_fb_helper_set_suspend_unlocked(struct drm_fb_helper *fb_helper,
772 					bool suspend)
773 {
774 	if (!fb_helper || !fb_helper->info)
775 		return;
776 
777 	/* make sure there's no pending/ongoing resume */
778 	flush_work(&fb_helper->resume_work);
779 
780 	if (suspend) {
781 		if (fb_helper->info->state != FBINFO_STATE_RUNNING)
782 			return;
783 
784 		console_lock();
785 
786 	} else {
787 		if (fb_helper->info->state == FBINFO_STATE_RUNNING)
788 			return;
789 
790 		if (!console_trylock()) {
791 			schedule_work(&fb_helper->resume_work);
792 			return;
793 		}
794 	}
795 
796 	fb_set_suspend(fb_helper->info, suspend);
797 	console_unlock();
798 }
799 EXPORT_SYMBOL(drm_fb_helper_set_suspend_unlocked);
800 
801 static int setcmap_pseudo_palette(struct fb_cmap *cmap, struct fb_info *info)
802 {
803 	u32 *palette = (u32 *)info->pseudo_palette;
804 	int i;
805 
806 	if (cmap->start + cmap->len > 16)
807 		return -EINVAL;
808 
809 	for (i = 0; i < cmap->len; ++i) {
810 		u16 red = cmap->red[i];
811 		u16 green = cmap->green[i];
812 		u16 blue = cmap->blue[i];
813 		u32 value;
814 
815 		red >>= 16 - info->var.red.length;
816 		green >>= 16 - info->var.green.length;
817 		blue >>= 16 - info->var.blue.length;
818 		value = (red << info->var.red.offset) |
819 			(green << info->var.green.offset) |
820 			(blue << info->var.blue.offset);
821 		if (info->var.transp.length > 0) {
822 			u32 mask = (1 << info->var.transp.length) - 1;
823 
824 			mask <<= info->var.transp.offset;
825 			value |= mask;
826 		}
827 		palette[cmap->start + i] = value;
828 	}
829 
830 	return 0;
831 }
832 
833 static int setcmap_legacy(struct fb_cmap *cmap, struct fb_info *info)
834 {
835 	struct drm_fb_helper *fb_helper = info->par;
836 	struct drm_mode_set *modeset;
837 	struct drm_crtc *crtc;
838 	u16 *r, *g, *b;
839 	int ret = 0;
840 
841 	drm_modeset_lock_all(fb_helper->dev);
842 	drm_client_for_each_modeset(modeset, &fb_helper->client) {
843 		crtc = modeset->crtc;
844 		if (!crtc->funcs->gamma_set || !crtc->gamma_size) {
845 			ret = -EINVAL;
846 			goto out;
847 		}
848 
849 		if (cmap->start + cmap->len > crtc->gamma_size) {
850 			ret = -EINVAL;
851 			goto out;
852 		}
853 
854 		r = crtc->gamma_store;
855 		g = r + crtc->gamma_size;
856 		b = g + crtc->gamma_size;
857 
858 		memcpy(r + cmap->start, cmap->red, cmap->len * sizeof(*r));
859 		memcpy(g + cmap->start, cmap->green, cmap->len * sizeof(*g));
860 		memcpy(b + cmap->start, cmap->blue, cmap->len * sizeof(*b));
861 
862 		ret = crtc->funcs->gamma_set(crtc, r, g, b,
863 					     crtc->gamma_size, NULL);
864 		if (ret)
865 			goto out;
866 	}
867 out:
868 	drm_modeset_unlock_all(fb_helper->dev);
869 
870 	return ret;
871 }
872 
873 static struct drm_property_blob *setcmap_new_gamma_lut(struct drm_crtc *crtc,
874 						       struct fb_cmap *cmap)
875 {
876 	struct drm_device *dev = crtc->dev;
877 	struct drm_property_blob *gamma_lut;
878 	struct drm_color_lut *lut;
879 	int size = crtc->gamma_size;
880 	int i;
881 
882 	if (!size || cmap->start + cmap->len > size)
883 		return ERR_PTR(-EINVAL);
884 
885 	gamma_lut = drm_property_create_blob(dev, sizeof(*lut) * size, NULL);
886 	if (IS_ERR(gamma_lut))
887 		return gamma_lut;
888 
889 	lut = gamma_lut->data;
890 	if (cmap->start || cmap->len != size) {
891 		u16 *r = crtc->gamma_store;
892 		u16 *g = r + crtc->gamma_size;
893 		u16 *b = g + crtc->gamma_size;
894 
895 		for (i = 0; i < cmap->start; i++) {
896 			lut[i].red = r[i];
897 			lut[i].green = g[i];
898 			lut[i].blue = b[i];
899 		}
900 		for (i = cmap->start + cmap->len; i < size; i++) {
901 			lut[i].red = r[i];
902 			lut[i].green = g[i];
903 			lut[i].blue = b[i];
904 		}
905 	}
906 
907 	for (i = 0; i < cmap->len; i++) {
908 		lut[cmap->start + i].red = cmap->red[i];
909 		lut[cmap->start + i].green = cmap->green[i];
910 		lut[cmap->start + i].blue = cmap->blue[i];
911 	}
912 
913 	return gamma_lut;
914 }
915 
916 static int setcmap_atomic(struct fb_cmap *cmap, struct fb_info *info)
917 {
918 	struct drm_fb_helper *fb_helper = info->par;
919 	struct drm_device *dev = fb_helper->dev;
920 	struct drm_property_blob *gamma_lut = NULL;
921 	struct drm_modeset_acquire_ctx ctx;
922 	struct drm_crtc_state *crtc_state;
923 	struct drm_atomic_state *state;
924 	struct drm_mode_set *modeset;
925 	struct drm_crtc *crtc;
926 	u16 *r, *g, *b;
927 	bool replaced;
928 	int ret = 0;
929 
930 	drm_modeset_acquire_init(&ctx, 0);
931 
932 	state = drm_atomic_state_alloc(dev);
933 	if (!state) {
934 		ret = -ENOMEM;
935 		goto out_ctx;
936 	}
937 
938 	state->acquire_ctx = &ctx;
939 retry:
940 	drm_client_for_each_modeset(modeset, &fb_helper->client) {
941 		crtc = modeset->crtc;
942 
943 		if (!gamma_lut)
944 			gamma_lut = setcmap_new_gamma_lut(crtc, cmap);
945 		if (IS_ERR(gamma_lut)) {
946 			ret = PTR_ERR(gamma_lut);
947 			gamma_lut = NULL;
948 			goto out_state;
949 		}
950 
951 		crtc_state = drm_atomic_get_crtc_state(state, crtc);
952 		if (IS_ERR(crtc_state)) {
953 			ret = PTR_ERR(crtc_state);
954 			goto out_state;
955 		}
956 
957 		/*
958 		 * FIXME: This always uses gamma_lut. Some HW have only
959 		 * degamma_lut, in which case we should reset gamma_lut and set
960 		 * degamma_lut. See drm_crtc_legacy_gamma_set().
961 		 */
962 		replaced  = drm_property_replace_blob(&crtc_state->degamma_lut,
963 						      NULL);
964 		replaced |= drm_property_replace_blob(&crtc_state->ctm, NULL);
965 		replaced |= drm_property_replace_blob(&crtc_state->gamma_lut,
966 						      gamma_lut);
967 		crtc_state->color_mgmt_changed |= replaced;
968 	}
969 
970 	ret = drm_atomic_commit(state);
971 	if (ret)
972 		goto out_state;
973 
974 	drm_client_for_each_modeset(modeset, &fb_helper->client) {
975 		crtc = modeset->crtc;
976 
977 		r = crtc->gamma_store;
978 		g = r + crtc->gamma_size;
979 		b = g + crtc->gamma_size;
980 
981 		memcpy(r + cmap->start, cmap->red, cmap->len * sizeof(*r));
982 		memcpy(g + cmap->start, cmap->green, cmap->len * sizeof(*g));
983 		memcpy(b + cmap->start, cmap->blue, cmap->len * sizeof(*b));
984 	}
985 
986 out_state:
987 	if (ret == -EDEADLK)
988 		goto backoff;
989 
990 	drm_property_blob_put(gamma_lut);
991 	drm_atomic_state_put(state);
992 out_ctx:
993 	drm_modeset_drop_locks(&ctx);
994 	drm_modeset_acquire_fini(&ctx);
995 
996 	return ret;
997 
998 backoff:
999 	drm_atomic_state_clear(state);
1000 	drm_modeset_backoff(&ctx);
1001 	goto retry;
1002 }
1003 
1004 /**
1005  * drm_fb_helper_setcmap - implementation for &fb_ops.fb_setcmap
1006  * @cmap: cmap to set
1007  * @info: fbdev registered by the helper
1008  */
1009 int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
1010 {
1011 	struct drm_fb_helper *fb_helper = info->par;
1012 	struct drm_device *dev = fb_helper->dev;
1013 	int ret;
1014 
1015 	if (oops_in_progress)
1016 		return -EBUSY;
1017 
1018 	mutex_lock(&fb_helper->lock);
1019 
1020 	if (!drm_master_internal_acquire(dev)) {
1021 		ret = -EBUSY;
1022 		goto unlock;
1023 	}
1024 
1025 	mutex_lock(&fb_helper->client.modeset_mutex);
1026 	if (info->fix.visual == FB_VISUAL_TRUECOLOR)
1027 		ret = setcmap_pseudo_palette(cmap, info);
1028 	else if (drm_drv_uses_atomic_modeset(fb_helper->dev))
1029 		ret = setcmap_atomic(cmap, info);
1030 	else
1031 		ret = setcmap_legacy(cmap, info);
1032 	mutex_unlock(&fb_helper->client.modeset_mutex);
1033 
1034 	drm_master_internal_release(dev);
1035 unlock:
1036 	mutex_unlock(&fb_helper->lock);
1037 
1038 	return ret;
1039 }
1040 EXPORT_SYMBOL(drm_fb_helper_setcmap);
1041 
1042 /**
1043  * drm_fb_helper_ioctl - legacy ioctl implementation
1044  * @info: fbdev registered by the helper
1045  * @cmd: ioctl command
1046  * @arg: ioctl argument
1047  *
1048  * A helper to implement the standard fbdev ioctl. Only
1049  * FBIO_WAITFORVSYNC is implemented for now.
1050  */
1051 int drm_fb_helper_ioctl(struct fb_info *info, unsigned int cmd,
1052 			unsigned long arg)
1053 {
1054 	struct drm_fb_helper *fb_helper = info->par;
1055 	struct drm_device *dev = fb_helper->dev;
1056 	struct drm_crtc *crtc;
1057 	int ret = 0;
1058 
1059 	mutex_lock(&fb_helper->lock);
1060 	if (!drm_master_internal_acquire(dev)) {
1061 		ret = -EBUSY;
1062 		goto unlock;
1063 	}
1064 
1065 	switch (cmd) {
1066 	case FBIO_WAITFORVSYNC:
1067 		/*
1068 		 * Only consider the first CRTC.
1069 		 *
1070 		 * This ioctl is supposed to take the CRTC number as
1071 		 * an argument, but in fbdev times, what that number
1072 		 * was supposed to be was quite unclear, different
1073 		 * drivers were passing that argument differently
1074 		 * (some by reference, some by value), and most of the
1075 		 * userspace applications were just hardcoding 0 as an
1076 		 * argument.
1077 		 *
1078 		 * The first CRTC should be the integrated panel on
1079 		 * most drivers, so this is the best choice we can
1080 		 * make. If we're not smart enough here, one should
1081 		 * just consider switch the userspace to KMS.
1082 		 */
1083 		crtc = fb_helper->client.modesets[0].crtc;
1084 
1085 		/*
1086 		 * Only wait for a vblank event if the CRTC is
1087 		 * enabled, otherwise just don't do anythintg,
1088 		 * not even report an error.
1089 		 */
1090 		ret = drm_crtc_vblank_get(crtc);
1091 		if (!ret) {
1092 			drm_crtc_wait_one_vblank(crtc);
1093 			drm_crtc_vblank_put(crtc);
1094 		}
1095 
1096 		ret = 0;
1097 		break;
1098 	default:
1099 		ret = -ENOTTY;
1100 	}
1101 
1102 	drm_master_internal_release(dev);
1103 unlock:
1104 	mutex_unlock(&fb_helper->lock);
1105 	return ret;
1106 }
1107 EXPORT_SYMBOL(drm_fb_helper_ioctl);
1108 
1109 static bool drm_fb_pixel_format_equal(const struct fb_var_screeninfo *var_1,
1110 				      const struct fb_var_screeninfo *var_2)
1111 {
1112 	return var_1->bits_per_pixel == var_2->bits_per_pixel &&
1113 	       var_1->grayscale == var_2->grayscale &&
1114 	       var_1->red.offset == var_2->red.offset &&
1115 	       var_1->red.length == var_2->red.length &&
1116 	       var_1->red.msb_right == var_2->red.msb_right &&
1117 	       var_1->green.offset == var_2->green.offset &&
1118 	       var_1->green.length == var_2->green.length &&
1119 	       var_1->green.msb_right == var_2->green.msb_right &&
1120 	       var_1->blue.offset == var_2->blue.offset &&
1121 	       var_1->blue.length == var_2->blue.length &&
1122 	       var_1->blue.msb_right == var_2->blue.msb_right &&
1123 	       var_1->transp.offset == var_2->transp.offset &&
1124 	       var_1->transp.length == var_2->transp.length &&
1125 	       var_1->transp.msb_right == var_2->transp.msb_right;
1126 }
1127 
1128 static void drm_fb_helper_fill_pixel_fmt(struct fb_var_screeninfo *var,
1129 					 const struct drm_format_info *format)
1130 {
1131 	u8 depth = format->depth;
1132 
1133 	if (format->is_color_indexed) {
1134 		var->red.offset = 0;
1135 		var->green.offset = 0;
1136 		var->blue.offset = 0;
1137 		var->red.length = depth;
1138 		var->green.length = depth;
1139 		var->blue.length = depth;
1140 		var->transp.offset = 0;
1141 		var->transp.length = 0;
1142 		return;
1143 	}
1144 
1145 	switch (depth) {
1146 	case 15:
1147 		var->red.offset = 10;
1148 		var->green.offset = 5;
1149 		var->blue.offset = 0;
1150 		var->red.length = 5;
1151 		var->green.length = 5;
1152 		var->blue.length = 5;
1153 		var->transp.offset = 15;
1154 		var->transp.length = 1;
1155 		break;
1156 	case 16:
1157 		var->red.offset = 11;
1158 		var->green.offset = 5;
1159 		var->blue.offset = 0;
1160 		var->red.length = 5;
1161 		var->green.length = 6;
1162 		var->blue.length = 5;
1163 		var->transp.offset = 0;
1164 		break;
1165 	case 24:
1166 		var->red.offset = 16;
1167 		var->green.offset = 8;
1168 		var->blue.offset = 0;
1169 		var->red.length = 8;
1170 		var->green.length = 8;
1171 		var->blue.length = 8;
1172 		var->transp.offset = 0;
1173 		var->transp.length = 0;
1174 		break;
1175 	case 32:
1176 		var->red.offset = 16;
1177 		var->green.offset = 8;
1178 		var->blue.offset = 0;
1179 		var->red.length = 8;
1180 		var->green.length = 8;
1181 		var->blue.length = 8;
1182 		var->transp.offset = 24;
1183 		var->transp.length = 8;
1184 		break;
1185 	default:
1186 		break;
1187 	}
1188 }
1189 
1190 static void __fill_var(struct fb_var_screeninfo *var, struct fb_info *info,
1191 		       struct drm_framebuffer *fb)
1192 {
1193 	int i;
1194 
1195 	var->xres_virtual = fb->width;
1196 	var->yres_virtual = fb->height;
1197 	var->accel_flags = 0;
1198 	var->bits_per_pixel = drm_format_info_bpp(fb->format, 0);
1199 
1200 	var->height = info->var.height;
1201 	var->width = info->var.width;
1202 
1203 	var->left_margin = var->right_margin = 0;
1204 	var->upper_margin = var->lower_margin = 0;
1205 	var->hsync_len = var->vsync_len = 0;
1206 	var->sync = var->vmode = 0;
1207 	var->rotate = 0;
1208 	var->colorspace = 0;
1209 	for (i = 0; i < 4; i++)
1210 		var->reserved[i] = 0;
1211 }
1212 
1213 /**
1214  * drm_fb_helper_check_var - implementation for &fb_ops.fb_check_var
1215  * @var: screeninfo to check
1216  * @info: fbdev registered by the helper
1217  */
1218 int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
1219 			    struct fb_info *info)
1220 {
1221 	struct drm_fb_helper *fb_helper = info->par;
1222 	struct drm_framebuffer *fb = fb_helper->fb;
1223 	const struct drm_format_info *format = fb->format;
1224 	struct drm_device *dev = fb_helper->dev;
1225 	unsigned int bpp;
1226 
1227 	if (in_dbg_master())
1228 		return -EINVAL;
1229 
1230 	if (var->pixclock != 0) {
1231 		drm_dbg_kms(dev, "fbdev emulation doesn't support changing the pixel clock, value of pixclock is ignored\n");
1232 		var->pixclock = 0;
1233 	}
1234 
1235 	switch (format->format) {
1236 	case DRM_FORMAT_C1:
1237 	case DRM_FORMAT_C2:
1238 	case DRM_FORMAT_C4:
1239 		/* supported format with sub-byte pixels */
1240 		break;
1241 
1242 	default:
1243 		if ((drm_format_info_block_width(format, 0) > 1) ||
1244 		    (drm_format_info_block_height(format, 0) > 1))
1245 			return -EINVAL;
1246 		break;
1247 	}
1248 
1249 	/*
1250 	 * Changes struct fb_var_screeninfo are currently not pushed back
1251 	 * to KMS, hence fail if different settings are requested.
1252 	 */
1253 	bpp = drm_format_info_bpp(format, 0);
1254 	if (var->bits_per_pixel > bpp ||
1255 	    var->xres > fb->width || var->yres > fb->height ||
1256 	    var->xres_virtual > fb->width || var->yres_virtual > fb->height) {
1257 		drm_dbg_kms(dev, "fb requested width/height/bpp can't fit in current fb "
1258 			  "request %dx%d-%d (virtual %dx%d) > %dx%d-%d\n",
1259 			  var->xres, var->yres, var->bits_per_pixel,
1260 			  var->xres_virtual, var->yres_virtual,
1261 			  fb->width, fb->height, bpp);
1262 		return -EINVAL;
1263 	}
1264 
1265 	__fill_var(var, info, fb);
1266 
1267 	/*
1268 	 * fb_pan_display() validates this, but fb_set_par() doesn't and just
1269 	 * falls over. Note that __fill_var above adjusts y/res_virtual.
1270 	 */
1271 	if (var->yoffset > var->yres_virtual - var->yres ||
1272 	    var->xoffset > var->xres_virtual - var->xres)
1273 		return -EINVAL;
1274 
1275 	/* We neither support grayscale nor FOURCC (also stored in here). */
1276 	if (var->grayscale > 0)
1277 		return -EINVAL;
1278 
1279 	if (var->nonstd)
1280 		return -EINVAL;
1281 
1282 	/*
1283 	 * Workaround for SDL 1.2, which is known to be setting all pixel format
1284 	 * fields values to zero in some cases. We treat this situation as a
1285 	 * kind of "use some reasonable autodetected values".
1286 	 */
1287 	if (!var->red.offset     && !var->green.offset    &&
1288 	    !var->blue.offset    && !var->transp.offset   &&
1289 	    !var->red.length     && !var->green.length    &&
1290 	    !var->blue.length    && !var->transp.length   &&
1291 	    !var->red.msb_right  && !var->green.msb_right &&
1292 	    !var->blue.msb_right && !var->transp.msb_right) {
1293 		drm_fb_helper_fill_pixel_fmt(var, format);
1294 	}
1295 
1296 	/*
1297 	 * drm fbdev emulation doesn't support changing the pixel format at all,
1298 	 * so reject all pixel format changing requests.
1299 	 */
1300 	if (!drm_fb_pixel_format_equal(var, &info->var)) {
1301 		drm_dbg_kms(dev, "fbdev emulation doesn't support changing the pixel format\n");
1302 		return -EINVAL;
1303 	}
1304 
1305 	return 0;
1306 }
1307 EXPORT_SYMBOL(drm_fb_helper_check_var);
1308 
1309 /**
1310  * drm_fb_helper_set_par - implementation for &fb_ops.fb_set_par
1311  * @info: fbdev registered by the helper
1312  *
1313  * This will let fbcon do the mode init and is called at initialization time by
1314  * the fbdev core when registering the driver, and later on through the hotplug
1315  * callback.
1316  */
1317 int drm_fb_helper_set_par(struct fb_info *info)
1318 {
1319 	struct drm_fb_helper *fb_helper = info->par;
1320 	struct fb_var_screeninfo *var = &info->var;
1321 	bool force;
1322 
1323 	if (oops_in_progress)
1324 		return -EBUSY;
1325 
1326 	/*
1327 	 * Normally we want to make sure that a kms master takes precedence over
1328 	 * fbdev, to avoid fbdev flickering and occasionally stealing the
1329 	 * display status. But Xorg first sets the vt back to text mode using
1330 	 * the KDSET IOCTL with KD_TEXT, and only after that drops the master
1331 	 * status when exiting.
1332 	 *
1333 	 * In the past this was caught by drm_fb_helper_lastclose(), but on
1334 	 * modern systems where logind always keeps a drm fd open to orchestrate
1335 	 * the vt switching, this doesn't work.
1336 	 *
1337 	 * To not break the userspace ABI we have this special case here, which
1338 	 * is only used for the above case. Everything else uses the normal
1339 	 * commit function, which ensures that we never steal the display from
1340 	 * an active drm master.
1341 	 */
1342 	force = var->activate & FB_ACTIVATE_KD_TEXT;
1343 
1344 	__drm_fb_helper_restore_fbdev_mode_unlocked(fb_helper, force);
1345 
1346 	return 0;
1347 }
1348 EXPORT_SYMBOL(drm_fb_helper_set_par);
1349 
1350 static void pan_set(struct drm_fb_helper *fb_helper, int x, int y)
1351 {
1352 	struct drm_mode_set *mode_set;
1353 
1354 	mutex_lock(&fb_helper->client.modeset_mutex);
1355 	drm_client_for_each_modeset(mode_set, &fb_helper->client) {
1356 		mode_set->x = x;
1357 		mode_set->y = y;
1358 	}
1359 	mutex_unlock(&fb_helper->client.modeset_mutex);
1360 }
1361 
1362 static int pan_display_atomic(struct fb_var_screeninfo *var,
1363 			      struct fb_info *info)
1364 {
1365 	struct drm_fb_helper *fb_helper = info->par;
1366 	int ret;
1367 
1368 	pan_set(fb_helper, var->xoffset, var->yoffset);
1369 
1370 	ret = drm_client_modeset_commit_locked(&fb_helper->client);
1371 	if (!ret) {
1372 		info->var.xoffset = var->xoffset;
1373 		info->var.yoffset = var->yoffset;
1374 	} else
1375 		pan_set(fb_helper, info->var.xoffset, info->var.yoffset);
1376 
1377 	return ret;
1378 }
1379 
1380 static int pan_display_legacy(struct fb_var_screeninfo *var,
1381 			      struct fb_info *info)
1382 {
1383 	struct drm_fb_helper *fb_helper = info->par;
1384 	struct drm_client_dev *client = &fb_helper->client;
1385 	struct drm_mode_set *modeset;
1386 	int ret = 0;
1387 
1388 	mutex_lock(&client->modeset_mutex);
1389 	drm_modeset_lock_all(fb_helper->dev);
1390 	drm_client_for_each_modeset(modeset, client) {
1391 		modeset->x = var->xoffset;
1392 		modeset->y = var->yoffset;
1393 
1394 		if (modeset->num_connectors) {
1395 			ret = drm_mode_set_config_internal(modeset);
1396 			if (!ret) {
1397 				info->var.xoffset = var->xoffset;
1398 				info->var.yoffset = var->yoffset;
1399 			}
1400 		}
1401 	}
1402 	drm_modeset_unlock_all(fb_helper->dev);
1403 	mutex_unlock(&client->modeset_mutex);
1404 
1405 	return ret;
1406 }
1407 
1408 /**
1409  * drm_fb_helper_pan_display - implementation for &fb_ops.fb_pan_display
1410  * @var: updated screen information
1411  * @info: fbdev registered by the helper
1412  */
1413 int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
1414 			      struct fb_info *info)
1415 {
1416 	struct drm_fb_helper *fb_helper = info->par;
1417 	struct drm_device *dev = fb_helper->dev;
1418 	int ret;
1419 
1420 	if (oops_in_progress)
1421 		return -EBUSY;
1422 
1423 	mutex_lock(&fb_helper->lock);
1424 	if (!drm_master_internal_acquire(dev)) {
1425 		ret = -EBUSY;
1426 		goto unlock;
1427 	}
1428 
1429 	if (drm_drv_uses_atomic_modeset(dev))
1430 		ret = pan_display_atomic(var, info);
1431 	else
1432 		ret = pan_display_legacy(var, info);
1433 
1434 	drm_master_internal_release(dev);
1435 unlock:
1436 	mutex_unlock(&fb_helper->lock);
1437 
1438 	return ret;
1439 }
1440 EXPORT_SYMBOL(drm_fb_helper_pan_display);
1441 
1442 static uint32_t drm_fb_helper_find_format(struct drm_fb_helper *fb_helper, const uint32_t *formats,
1443 					  size_t format_count, uint32_t bpp, uint32_t depth)
1444 {
1445 	struct drm_device *dev = fb_helper->dev;
1446 	uint32_t format;
1447 	size_t i;
1448 
1449 	/*
1450 	 * Do not consider YUV or other complicated formats
1451 	 * for framebuffers. This means only legacy formats
1452 	 * are supported (fmt->depth is a legacy field), but
1453 	 * the framebuffer emulation can only deal with such
1454 	 * formats, specifically RGB/BGA formats.
1455 	 */
1456 	format = drm_mode_legacy_fb_format(bpp, depth);
1457 	if (!format)
1458 		goto err;
1459 
1460 	for (i = 0; i < format_count; ++i) {
1461 		if (formats[i] == format)
1462 			return format;
1463 	}
1464 
1465 err:
1466 	/* We found nothing. */
1467 	drm_warn(dev, "bpp/depth value of %u/%u not supported\n", bpp, depth);
1468 
1469 	return DRM_FORMAT_INVALID;
1470 }
1471 
1472 static uint32_t drm_fb_helper_find_color_mode_format(struct drm_fb_helper *fb_helper,
1473 						     const uint32_t *formats, size_t format_count,
1474 						     unsigned int color_mode)
1475 {
1476 	struct drm_device *dev = fb_helper->dev;
1477 	uint32_t bpp, depth;
1478 
1479 	switch (color_mode) {
1480 	case 1:
1481 	case 2:
1482 	case 4:
1483 	case 8:
1484 	case 16:
1485 	case 24:
1486 		bpp = depth = color_mode;
1487 		break;
1488 	case 15:
1489 		bpp = 16;
1490 		depth = 15;
1491 		break;
1492 	case 32:
1493 		bpp = 32;
1494 		depth = 24;
1495 		break;
1496 	default:
1497 		drm_info(dev, "unsupported color mode of %d\n", color_mode);
1498 		return DRM_FORMAT_INVALID;
1499 	}
1500 
1501 	return drm_fb_helper_find_format(fb_helper, formats, format_count, bpp, depth);
1502 }
1503 
1504 static int __drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper,
1505 				      struct drm_fb_helper_surface_size *sizes)
1506 {
1507 	struct drm_client_dev *client = &fb_helper->client;
1508 	struct drm_device *dev = fb_helper->dev;
1509 	int crtc_count = 0;
1510 	struct drm_connector_list_iter conn_iter;
1511 	struct drm_connector *connector;
1512 	struct drm_mode_set *mode_set;
1513 	uint32_t surface_format = DRM_FORMAT_INVALID;
1514 	const struct drm_format_info *info;
1515 
1516 	memset(sizes, 0, sizeof(*sizes));
1517 	sizes->fb_width = (u32)-1;
1518 	sizes->fb_height = (u32)-1;
1519 
1520 	drm_client_for_each_modeset(mode_set, client) {
1521 		struct drm_crtc *crtc = mode_set->crtc;
1522 		struct drm_plane *plane = crtc->primary;
1523 
1524 		drm_dbg_kms(dev, "test CRTC %u primary plane\n", drm_crtc_index(crtc));
1525 
1526 		drm_connector_list_iter_begin(fb_helper->dev, &conn_iter);
1527 		drm_client_for_each_connector_iter(connector, &conn_iter) {
1528 			struct drm_cmdline_mode *cmdline_mode = &connector->cmdline_mode;
1529 
1530 			if (!cmdline_mode->bpp_specified)
1531 				continue;
1532 
1533 			surface_format = drm_fb_helper_find_color_mode_format(fb_helper,
1534 									      plane->format_types,
1535 									      plane->format_count,
1536 									      cmdline_mode->bpp);
1537 			if (surface_format != DRM_FORMAT_INVALID)
1538 				break; /* found supported format */
1539 		}
1540 		drm_connector_list_iter_end(&conn_iter);
1541 
1542 		if (surface_format != DRM_FORMAT_INVALID)
1543 			break; /* found supported format */
1544 
1545 		/* try preferred color mode */
1546 		surface_format = drm_fb_helper_find_color_mode_format(fb_helper,
1547 								      plane->format_types,
1548 								      plane->format_count,
1549 								      fb_helper->preferred_bpp);
1550 		if (surface_format != DRM_FORMAT_INVALID)
1551 			break; /* found supported format */
1552 	}
1553 
1554 	if (surface_format == DRM_FORMAT_INVALID) {
1555 		/*
1556 		 * If none of the given color modes works, fall back
1557 		 * to XRGB8888. Drivers are expected to provide this
1558 		 * format for compatibility with legacy applications.
1559 		 */
1560 		drm_warn(dev, "No compatible format found\n");
1561 		surface_format = drm_driver_legacy_fb_format(dev, 32, 24);
1562 	}
1563 
1564 	info = drm_format_info(surface_format);
1565 	sizes->surface_bpp = drm_format_info_bpp(info, 0);
1566 	sizes->surface_depth = info->depth;
1567 
1568 	/* first up get a count of crtcs now in use and new min/maxes width/heights */
1569 	crtc_count = 0;
1570 	drm_client_for_each_modeset(mode_set, client) {
1571 		struct drm_display_mode *desired_mode;
1572 		int x, y, j;
1573 		/* in case of tile group, are we the last tile vert or horiz?
1574 		 * If no tile group you are always the last one both vertically
1575 		 * and horizontally
1576 		 */
1577 		bool lastv = true, lasth = true;
1578 
1579 		desired_mode = mode_set->mode;
1580 
1581 		if (!desired_mode)
1582 			continue;
1583 
1584 		crtc_count++;
1585 
1586 		x = mode_set->x;
1587 		y = mode_set->y;
1588 
1589 		sizes->surface_width  =
1590 			max_t(u32, desired_mode->hdisplay + x, sizes->surface_width);
1591 		sizes->surface_height =
1592 			max_t(u32, desired_mode->vdisplay + y, sizes->surface_height);
1593 
1594 		for (j = 0; j < mode_set->num_connectors; j++) {
1595 			struct drm_connector *connector = mode_set->connectors[j];
1596 
1597 			if (connector->has_tile &&
1598 			    desired_mode->hdisplay == connector->tile_h_size &&
1599 			    desired_mode->vdisplay == connector->tile_v_size) {
1600 				lasth = (connector->tile_h_loc == (connector->num_h_tile - 1));
1601 				lastv = (connector->tile_v_loc == (connector->num_v_tile - 1));
1602 				/* cloning to multiple tiles is just crazy-talk, so: */
1603 				break;
1604 			}
1605 		}
1606 
1607 		if (lasth)
1608 			sizes->fb_width  = min_t(u32, desired_mode->hdisplay + x, sizes->fb_width);
1609 		if (lastv)
1610 			sizes->fb_height = min_t(u32, desired_mode->vdisplay + y, sizes->fb_height);
1611 	}
1612 
1613 	if (crtc_count == 0 || sizes->fb_width == -1 || sizes->fb_height == -1) {
1614 		drm_info(dev, "Cannot find any crtc or sizes\n");
1615 		return -EAGAIN;
1616 	}
1617 
1618 	return 0;
1619 }
1620 
1621 static int drm_fb_helper_find_sizes(struct drm_fb_helper *fb_helper,
1622 				    struct drm_fb_helper_surface_size *sizes)
1623 {
1624 	struct drm_client_dev *client = &fb_helper->client;
1625 	struct drm_device *dev = fb_helper->dev;
1626 	struct drm_mode_config *config = &dev->mode_config;
1627 	int ret;
1628 
1629 	mutex_lock(&client->modeset_mutex);
1630 	ret = __drm_fb_helper_find_sizes(fb_helper, sizes);
1631 	mutex_unlock(&client->modeset_mutex);
1632 
1633 	if (ret)
1634 		return ret;
1635 
1636 	/* Handle our overallocation */
1637 	sizes->surface_height *= drm_fbdev_overalloc;
1638 	sizes->surface_height /= 100;
1639 	if (sizes->surface_height > config->max_height) {
1640 		drm_dbg_kms(dev, "Fbdev over-allocation too large; clamping height to %d\n",
1641 			    config->max_height);
1642 		sizes->surface_height = config->max_height;
1643 	}
1644 
1645 	return 0;
1646 }
1647 
1648 /*
1649  * Allocates the backing storage and sets up the fbdev info structure through
1650  * the ->fb_probe callback.
1651  */
1652 static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper)
1653 {
1654 	struct drm_client_dev *client = &fb_helper->client;
1655 	struct drm_device *dev = fb_helper->dev;
1656 	struct drm_fb_helper_surface_size sizes;
1657 	int ret;
1658 
1659 	ret = drm_fb_helper_find_sizes(fb_helper, &sizes);
1660 	if (ret) {
1661 		/* First time: disable all crtc's.. */
1662 		if (!fb_helper->deferred_setup)
1663 			drm_client_modeset_commit(client);
1664 		return ret;
1665 	}
1666 
1667 	/* push down into drivers */
1668 	ret = (*fb_helper->funcs->fb_probe)(fb_helper, &sizes);
1669 	if (ret < 0)
1670 		return ret;
1671 
1672 	strcpy(fb_helper->fb->comm, "[fbcon]");
1673 
1674 	/* Set the fb info for vgaswitcheroo clients. Does nothing otherwise. */
1675 	if (dev_is_pci(dev->dev))
1676 		vga_switcheroo_client_fb_set(to_pci_dev(dev->dev), fb_helper->info);
1677 
1678 	return 0;
1679 }
1680 
1681 static void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
1682 				   bool is_color_indexed)
1683 {
1684 	info->fix.type = FB_TYPE_PACKED_PIXELS;
1685 	info->fix.visual = is_color_indexed ? FB_VISUAL_PSEUDOCOLOR
1686 					    : FB_VISUAL_TRUECOLOR;
1687 	info->fix.mmio_start = 0;
1688 	info->fix.mmio_len = 0;
1689 	info->fix.type_aux = 0;
1690 	info->fix.xpanstep = 1; /* doing it in hw */
1691 	info->fix.ypanstep = 1; /* doing it in hw */
1692 	info->fix.ywrapstep = 0;
1693 	info->fix.accel = FB_ACCEL_NONE;
1694 
1695 	info->fix.line_length = pitch;
1696 }
1697 
1698 static void drm_fb_helper_fill_var(struct fb_info *info,
1699 				   struct drm_fb_helper *fb_helper,
1700 				   uint32_t fb_width, uint32_t fb_height)
1701 {
1702 	struct drm_framebuffer *fb = fb_helper->fb;
1703 	const struct drm_format_info *format = fb->format;
1704 
1705 	switch (format->format) {
1706 	case DRM_FORMAT_C1:
1707 	case DRM_FORMAT_C2:
1708 	case DRM_FORMAT_C4:
1709 		/* supported format with sub-byte pixels */
1710 		break;
1711 
1712 	default:
1713 		WARN_ON((drm_format_info_block_width(format, 0) > 1) ||
1714 			(drm_format_info_block_height(format, 0) > 1));
1715 		break;
1716 	}
1717 
1718 	info->pseudo_palette = fb_helper->pseudo_palette;
1719 	info->var.xoffset = 0;
1720 	info->var.yoffset = 0;
1721 	__fill_var(&info->var, info, fb);
1722 	info->var.activate = FB_ACTIVATE_NOW;
1723 
1724 	drm_fb_helper_fill_pixel_fmt(&info->var, format);
1725 
1726 	info->var.xres = fb_width;
1727 	info->var.yres = fb_height;
1728 }
1729 
1730 /**
1731  * drm_fb_helper_fill_info - initializes fbdev information
1732  * @info: fbdev instance to set up
1733  * @fb_helper: fb helper instance to use as template
1734  * @sizes: describes fbdev size and scanout surface size
1735  *
1736  * Sets up the variable and fixed fbdev metainformation from the given fb helper
1737  * instance and the drm framebuffer allocated in &drm_fb_helper.fb.
1738  *
1739  * Drivers should call this (or their equivalent setup code) from their
1740  * &drm_fb_helper_funcs.fb_probe callback after having allocated the fbdev
1741  * backing storage framebuffer.
1742  */
1743 void drm_fb_helper_fill_info(struct fb_info *info,
1744 			     struct drm_fb_helper *fb_helper,
1745 			     struct drm_fb_helper_surface_size *sizes)
1746 {
1747 	struct drm_framebuffer *fb = fb_helper->fb;
1748 
1749 	drm_fb_helper_fill_fix(info, fb->pitches[0],
1750 			       fb->format->is_color_indexed);
1751 	drm_fb_helper_fill_var(info, fb_helper,
1752 			       sizes->fb_width, sizes->fb_height);
1753 
1754 	info->par = fb_helper;
1755 	/*
1756 	 * The DRM drivers fbdev emulation device name can be confusing if the
1757 	 * driver name also has a "drm" suffix on it. Leading to names such as
1758 	 * "simpledrmdrmfb" in /proc/fb. Unfortunately, it's an uAPI and can't
1759 	 * be changed due user-space tools (e.g: pm-utils) matching against it.
1760 	 */
1761 	snprintf(info->fix.id, sizeof(info->fix.id), "%sdrmfb",
1762 		 fb_helper->dev->driver->name);
1763 
1764 }
1765 EXPORT_SYMBOL(drm_fb_helper_fill_info);
1766 
1767 /*
1768  * This is a continuation of drm_setup_crtcs() that sets up anything related
1769  * to the framebuffer. During initialization, drm_setup_crtcs() is called before
1770  * the framebuffer has been allocated (fb_helper->fb and fb_helper->info).
1771  * So, any setup that touches those fields needs to be done here instead of in
1772  * drm_setup_crtcs().
1773  */
1774 static void drm_setup_crtcs_fb(struct drm_fb_helper *fb_helper)
1775 {
1776 	struct drm_client_dev *client = &fb_helper->client;
1777 	struct drm_connector_list_iter conn_iter;
1778 	struct fb_info *info = fb_helper->info;
1779 	unsigned int rotation, sw_rotations = 0;
1780 	struct drm_connector *connector;
1781 	struct drm_mode_set *modeset;
1782 
1783 	mutex_lock(&client->modeset_mutex);
1784 	drm_client_for_each_modeset(modeset, client) {
1785 		if (!modeset->num_connectors)
1786 			continue;
1787 
1788 		modeset->fb = fb_helper->fb;
1789 
1790 		if (drm_client_rotation(modeset, &rotation))
1791 			/* Rotating in hardware, fbcon should not rotate */
1792 			sw_rotations |= DRM_MODE_ROTATE_0;
1793 		else
1794 			sw_rotations |= rotation;
1795 	}
1796 	mutex_unlock(&client->modeset_mutex);
1797 
1798 	drm_connector_list_iter_begin(fb_helper->dev, &conn_iter);
1799 	drm_client_for_each_connector_iter(connector, &conn_iter) {
1800 
1801 		/* use first connected connector for the physical dimensions */
1802 		if (connector->status == connector_status_connected) {
1803 			info->var.width = connector->display_info.width_mm;
1804 			info->var.height = connector->display_info.height_mm;
1805 			break;
1806 		}
1807 	}
1808 	drm_connector_list_iter_end(&conn_iter);
1809 
1810 	switch (sw_rotations) {
1811 	case DRM_MODE_ROTATE_0:
1812 		info->fbcon_rotate_hint = FB_ROTATE_UR;
1813 		break;
1814 	case DRM_MODE_ROTATE_90:
1815 		info->fbcon_rotate_hint = FB_ROTATE_CCW;
1816 		break;
1817 	case DRM_MODE_ROTATE_180:
1818 		info->fbcon_rotate_hint = FB_ROTATE_UD;
1819 		break;
1820 	case DRM_MODE_ROTATE_270:
1821 		info->fbcon_rotate_hint = FB_ROTATE_CW;
1822 		break;
1823 	default:
1824 		/*
1825 		 * Multiple bits are set / multiple rotations requested
1826 		 * fbcon cannot handle separate rotation settings per
1827 		 * output, so fallback to unrotated.
1828 		 */
1829 		info->fbcon_rotate_hint = FB_ROTATE_UR;
1830 	}
1831 }
1832 
1833 /* Note: Drops fb_helper->lock before returning. */
1834 static int
1835 __drm_fb_helper_initial_config_and_unlock(struct drm_fb_helper *fb_helper)
1836 {
1837 	struct drm_device *dev = fb_helper->dev;
1838 	struct fb_info *info;
1839 	unsigned int width, height;
1840 	int ret;
1841 
1842 	width = dev->mode_config.max_width;
1843 	height = dev->mode_config.max_height;
1844 
1845 	drm_client_modeset_probe(&fb_helper->client, width, height);
1846 	ret = drm_fb_helper_single_fb_probe(fb_helper);
1847 	if (ret < 0) {
1848 		if (ret == -EAGAIN) {
1849 			fb_helper->deferred_setup = true;
1850 			ret = 0;
1851 		}
1852 		mutex_unlock(&fb_helper->lock);
1853 
1854 		return ret;
1855 	}
1856 	drm_setup_crtcs_fb(fb_helper);
1857 
1858 	fb_helper->deferred_setup = false;
1859 
1860 	info = fb_helper->info;
1861 	info->var.pixclock = 0;
1862 
1863 	if (!drm_leak_fbdev_smem)
1864 		info->flags |= FBINFO_HIDE_SMEM_START;
1865 
1866 	/* Need to drop locks to avoid recursive deadlock in
1867 	 * register_framebuffer. This is ok because the only thing left to do is
1868 	 * register the fbdev emulation instance in kernel_fb_helper_list. */
1869 	mutex_unlock(&fb_helper->lock);
1870 
1871 	ret = register_framebuffer(info);
1872 	if (ret < 0)
1873 		return ret;
1874 
1875 	drm_info(dev, "fb%d: %s frame buffer device\n",
1876 		 info->node, info->fix.id);
1877 
1878 	mutex_lock(&kernel_fb_helper_lock);
1879 	if (list_empty(&kernel_fb_helper_list))
1880 		register_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
1881 
1882 	list_add(&fb_helper->kernel_fb_list, &kernel_fb_helper_list);
1883 	mutex_unlock(&kernel_fb_helper_lock);
1884 
1885 	return 0;
1886 }
1887 
1888 /**
1889  * drm_fb_helper_initial_config - setup a sane initial connector configuration
1890  * @fb_helper: fb_helper device struct
1891  *
1892  * Scans the CRTCs and connectors and tries to put together an initial setup.
1893  * At the moment, this is a cloned configuration across all heads with
1894  * a new framebuffer object as the backing store.
1895  *
1896  * Note that this also registers the fbdev and so allows userspace to call into
1897  * the driver through the fbdev interfaces.
1898  *
1899  * This function will call down into the &drm_fb_helper_funcs.fb_probe callback
1900  * to let the driver allocate and initialize the fbdev info structure and the
1901  * drm framebuffer used to back the fbdev. drm_fb_helper_fill_info() is provided
1902  * as a helper to setup simple default values for the fbdev info structure.
1903  *
1904  * HANG DEBUGGING:
1905  *
1906  * When you have fbcon support built-in or already loaded, this function will do
1907  * a full modeset to setup the fbdev console. Due to locking misdesign in the
1908  * VT/fbdev subsystem that entire modeset sequence has to be done while holding
1909  * console_lock. Until console_unlock is called no dmesg lines will be sent out
1910  * to consoles, not even serial console. This means when your driver crashes,
1911  * you will see absolutely nothing else but a system stuck in this function,
1912  * with no further output. Any kind of printk() you place within your own driver
1913  * or in the drm core modeset code will also never show up.
1914  *
1915  * Standard debug practice is to run the fbcon setup without taking the
1916  * console_lock as a hack, to be able to see backtraces and crashes on the
1917  * serial line. This can be done by setting the fb.lockless_register_fb=1 kernel
1918  * cmdline option.
1919  *
1920  * The other option is to just disable fbdev emulation since very likely the
1921  * first modeset from userspace will crash in the same way, and is even easier
1922  * to debug. This can be done by setting the drm_kms_helper.fbdev_emulation=0
1923  * kernel cmdline option.
1924  *
1925  * RETURNS:
1926  * Zero if everything went ok, nonzero otherwise.
1927  */
1928 int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper)
1929 {
1930 	int ret;
1931 
1932 	if (!drm_fbdev_emulation)
1933 		return 0;
1934 
1935 	mutex_lock(&fb_helper->lock);
1936 	ret = __drm_fb_helper_initial_config_and_unlock(fb_helper);
1937 
1938 	return ret;
1939 }
1940 EXPORT_SYMBOL(drm_fb_helper_initial_config);
1941 
1942 /**
1943  * drm_fb_helper_hotplug_event - respond to a hotplug notification by
1944  *                               probing all the outputs attached to the fb
1945  * @fb_helper: driver-allocated fbdev helper, can be NULL
1946  *
1947  * Scan the connectors attached to the fb_helper and try to put together a
1948  * setup after notification of a change in output configuration.
1949  *
1950  * Called at runtime, takes the mode config locks to be able to check/change the
1951  * modeset configuration. Must be run from process context (which usually means
1952  * either the output polling work or a work item launched from the driver's
1953  * hotplug interrupt).
1954  *
1955  * Note that drivers may call this even before calling
1956  * drm_fb_helper_initial_config but only after drm_fb_helper_init. This allows
1957  * for a race-free fbcon setup and will make sure that the fbdev emulation will
1958  * not miss any hotplug events.
1959  *
1960  * RETURNS:
1961  * 0 on success and a non-zero error code otherwise.
1962  */
1963 int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
1964 {
1965 	int err = 0;
1966 
1967 	if (!drm_fbdev_emulation || !fb_helper)
1968 		return 0;
1969 
1970 	mutex_lock(&fb_helper->lock);
1971 	if (fb_helper->deferred_setup) {
1972 		err = __drm_fb_helper_initial_config_and_unlock(fb_helper);
1973 		return err;
1974 	}
1975 
1976 	if (!fb_helper->fb || !drm_master_internal_acquire(fb_helper->dev)) {
1977 		fb_helper->delayed_hotplug = true;
1978 		mutex_unlock(&fb_helper->lock);
1979 		return err;
1980 	}
1981 
1982 	drm_master_internal_release(fb_helper->dev);
1983 
1984 	drm_dbg_kms(fb_helper->dev, "\n");
1985 
1986 	drm_client_modeset_probe(&fb_helper->client, fb_helper->fb->width, fb_helper->fb->height);
1987 	drm_setup_crtcs_fb(fb_helper);
1988 	mutex_unlock(&fb_helper->lock);
1989 
1990 	drm_fb_helper_set_par(fb_helper->info);
1991 
1992 	return 0;
1993 }
1994 EXPORT_SYMBOL(drm_fb_helper_hotplug_event);
1995 
1996 /**
1997  * drm_fb_helper_lastclose - DRM driver lastclose helper for fbdev emulation
1998  * @dev: DRM device
1999  *
2000  * This function can be used as the &drm_driver->lastclose callback for drivers
2001  * that only need to call drm_fb_helper_restore_fbdev_mode_unlocked().
2002  */
2003 void drm_fb_helper_lastclose(struct drm_device *dev)
2004 {
2005 	drm_fb_helper_restore_fbdev_mode_unlocked(dev->fb_helper);
2006 }
2007 EXPORT_SYMBOL(drm_fb_helper_lastclose);
2008 
2009 /**
2010  * drm_fb_helper_output_poll_changed - DRM mode config \.output_poll_changed
2011  *                                     helper for fbdev emulation
2012  * @dev: DRM device
2013  *
2014  * This function can be used as the
2015  * &drm_mode_config_funcs.output_poll_changed callback for drivers that only
2016  * need to call drm_fbdev.hotplug_event().
2017  */
2018 void drm_fb_helper_output_poll_changed(struct drm_device *dev)
2019 {
2020 	drm_fb_helper_hotplug_event(dev->fb_helper);
2021 }
2022 EXPORT_SYMBOL(drm_fb_helper_output_poll_changed);
2023