xref: /linux/drivers/video/fbdev/core/fbmem.c (revision fb7399cf2d0b33825b8039f95c45395c7deba25c)
1 /*
2  *  linux/drivers/video/fbmem.c
3  *
4  *  Copyright (C) 1994 Martin Schaller
5  *
6  *	2001 - Documented with DocBook
7  *	- Brad Douglas <brad@neruo.com>
8  *
9  * This file is subject to the terms and conditions of the GNU General Public
10  * License.  See the file COPYING in the main directory of this archive
11  * for more details.
12  */
13 
14 #include <linux/console.h>
15 #include <linux/export.h>
16 #include <linux/fb.h>
17 #include <linux/fbcon.h>
18 #include <linux/lcd.h>
19 #include <linux/leds.h>
20 
21 #include <video/nomodeset.h>
22 
23 #include "fb_internal.h"
24 
25     /*
26      *  Frame buffer device initialization and setup routines
27      */
28 
29 #define FBPIXMAPSIZE	(1024 * 8)
30 
31 struct class *fb_class;
32 
33 DEFINE_MUTEX(registration_lock);
34 struct fb_info *registered_fb[FB_MAX] __read_mostly;
35 int num_registered_fb __read_mostly;
36 #define for_each_registered_fb(i)		\
37 	for (i = 0; i < FB_MAX; i++)		\
38 		if (!registered_fb[i]) {} else
39 
40 struct fb_info *get_fb_info(unsigned int idx)
41 {
42 	struct fb_info *fb_info;
43 
44 	if (idx >= FB_MAX)
45 		return ERR_PTR(-ENODEV);
46 
47 	mutex_lock(&registration_lock);
48 	fb_info = registered_fb[idx];
49 	if (fb_info)
50 		refcount_inc(&fb_info->count);
51 	mutex_unlock(&registration_lock);
52 
53 	return fb_info;
54 }
55 
56 void put_fb_info(struct fb_info *fb_info)
57 {
58 	if (!refcount_dec_and_test(&fb_info->count))
59 		return;
60 	if (fb_info->fbops->fb_destroy)
61 		fb_info->fbops->fb_destroy(fb_info);
62 }
63 
64 /*
65  * Helpers
66  */
67 
68 int fb_get_color_depth(struct fb_var_screeninfo *var,
69 		       struct fb_fix_screeninfo *fix)
70 {
71 	int depth = 0;
72 
73 	if (fix->visual == FB_VISUAL_MONO01 ||
74 	    fix->visual == FB_VISUAL_MONO10)
75 		depth = 1;
76 	else {
77 		if (var->green.length == var->blue.length &&
78 		    var->green.length == var->red.length &&
79 		    var->green.offset == var->blue.offset &&
80 		    var->green.offset == var->red.offset)
81 			depth = var->green.length;
82 		else
83 			depth = var->green.length + var->red.length +
84 				var->blue.length;
85 	}
86 
87 	return depth;
88 }
89 EXPORT_SYMBOL(fb_get_color_depth);
90 
91 /*
92  * Data padding functions.
93  */
94 void fb_pad_aligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 s_pitch, u32 height)
95 {
96 	__fb_pad_aligned_buffer(dst, d_pitch, src, s_pitch, height);
97 }
98 EXPORT_SYMBOL(fb_pad_aligned_buffer);
99 
100 void fb_pad_unaligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 idx, u32 height,
101 				u32 shift_high, u32 shift_low, u32 mod)
102 {
103 	u8 mask = (u8) (0xfff << shift_high), tmp;
104 	int i, j;
105 
106 	for (i = height; i--; ) {
107 		for (j = 0; j < idx; j++) {
108 			tmp = dst[j];
109 			tmp &= mask;
110 			tmp |= *src >> shift_low;
111 			dst[j] = tmp;
112 			tmp = *src << shift_high;
113 			dst[j+1] = tmp;
114 			src++;
115 		}
116 		tmp = dst[idx];
117 		tmp &= mask;
118 		tmp |= *src >> shift_low;
119 		dst[idx] = tmp;
120 		if (shift_high < mod) {
121 			tmp = *src << shift_high;
122 			dst[idx+1] = tmp;
123 		}
124 		src++;
125 		dst += d_pitch;
126 	}
127 }
128 EXPORT_SYMBOL(fb_pad_unaligned_buffer);
129 
130 /*
131  * we need to lock this section since fb_cursor
132  * may use fb_imageblit()
133  */
134 char* fb_get_buffer_offset(struct fb_info *info, struct fb_pixmap *buf, u32 size)
135 {
136 	u32 align = buf->buf_align - 1, offset;
137 	char *addr = buf->addr;
138 
139 	/* If IO mapped, we need to sync before access, no sharing of
140 	 * the pixmap is done
141 	 */
142 	if (buf->flags & FB_PIXMAP_IO) {
143 		if (info->fbops->fb_sync && (buf->flags & FB_PIXMAP_SYNC))
144 			info->fbops->fb_sync(info);
145 		return addr;
146 	}
147 
148 	/* See if we fit in the remaining pixmap space */
149 	offset = buf->offset + align;
150 	offset &= ~align;
151 	if (offset + size > buf->size) {
152 		/* We do not fit. In order to be able to re-use the buffer,
153 		 * we must ensure no asynchronous DMA'ing or whatever operation
154 		 * is in progress, we sync for that.
155 		 */
156 		if (info->fbops->fb_sync && (buf->flags & FB_PIXMAP_SYNC))
157 			info->fbops->fb_sync(info);
158 		offset = 0;
159 	}
160 	buf->offset = offset + size;
161 	addr += offset;
162 
163 	return addr;
164 }
165 EXPORT_SYMBOL(fb_get_buffer_offset);
166 
167 int
168 fb_pan_display(struct fb_info *info, struct fb_var_screeninfo *var)
169 {
170 	struct fb_fix_screeninfo *fix = &info->fix;
171 	unsigned int yres = info->var.yres;
172 	int err = 0;
173 
174 	if (var->yoffset > 0) {
175 		if (var->vmode & FB_VMODE_YWRAP) {
176 			if (!fix->ywrapstep || (var->yoffset % fix->ywrapstep))
177 				err = -EINVAL;
178 			else
179 				yres = 0;
180 		} else if (!fix->ypanstep || (var->yoffset % fix->ypanstep))
181 			err = -EINVAL;
182 	}
183 
184 	if (var->xoffset > 0 && (!fix->xpanstep ||
185 				 (var->xoffset % fix->xpanstep)))
186 		err = -EINVAL;
187 
188 	if (err || !info->fbops->fb_pan_display ||
189 	    var->yoffset > info->var.yres_virtual - yres ||
190 	    var->xoffset > info->var.xres_virtual - info->var.xres)
191 		return -EINVAL;
192 
193 	if ((err = info->fbops->fb_pan_display(var, info)))
194 		return err;
195 	info->var.xoffset = var->xoffset;
196 	info->var.yoffset = var->yoffset;
197 	if (var->vmode & FB_VMODE_YWRAP)
198 		info->var.vmode |= FB_VMODE_YWRAP;
199 	else
200 		info->var.vmode &= ~FB_VMODE_YWRAP;
201 	return 0;
202 }
203 EXPORT_SYMBOL(fb_pan_display);
204 
205 static int fb_check_caps(struct fb_info *info, struct fb_var_screeninfo *var,
206 			 u32 activate)
207 {
208 	struct fb_blit_caps caps, fbcaps;
209 	int err = 0;
210 
211 	memset(&caps, 0, sizeof(caps));
212 	memset(&fbcaps, 0, sizeof(fbcaps));
213 	caps.flags = (activate & FB_ACTIVATE_ALL) ? 1 : 0;
214 	fbcon_get_requirement(info, &caps);
215 	info->fbops->fb_get_caps(info, &fbcaps, var);
216 
217 	if (!bitmap_subset(caps.x, fbcaps.x, FB_MAX_BLIT_WIDTH) ||
218 	    !bitmap_subset(caps.y, fbcaps.y, FB_MAX_BLIT_HEIGHT) ||
219 	    (fbcaps.len < caps.len))
220 		err = -EINVAL;
221 
222 	return err;
223 }
224 
225 static void fb_lcd_notify_mode_change(struct fb_info *info,
226 				      struct fb_videomode *mode)
227 {
228 	lcd_notify_mode_change_all(info->device, mode->xres, mode->yres);
229 }
230 
231 int
232 fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var)
233 {
234 	int ret = 0;
235 	u32 activate;
236 	struct fb_var_screeninfo old_var;
237 	struct fb_videomode mode;
238 	u32 unused;
239 
240 	if (var->activate & FB_ACTIVATE_INV_MODE) {
241 		struct fb_videomode mode1, mode2;
242 
243 		fb_var_to_videomode(&mode1, var);
244 		fb_var_to_videomode(&mode2, &info->var);
245 		/* make sure we don't delete the videomode of current var */
246 		ret = fb_mode_is_equal(&mode1, &mode2);
247 		if (!ret) {
248 			ret = fbcon_mode_deleted(info, &mode1);
249 			if (!ret)
250 				fb_delete_videomode(&mode1, &info->modelist);
251 		}
252 
253 		return ret ? -EINVAL : 0;
254 	}
255 
256 	if (!(var->activate & FB_ACTIVATE_FORCE) &&
257 	    !memcmp(&info->var, var, sizeof(struct fb_var_screeninfo)))
258 		return 0;
259 
260 	activate = var->activate;
261 
262 	/* When using FOURCC mode, make sure the red, green, blue and
263 	 * transp fields are set to 0.
264 	 */
265 	if ((info->fix.capabilities & FB_CAP_FOURCC) &&
266 	    var->grayscale > 1) {
267 		if (var->red.offset     || var->green.offset    ||
268 		    var->blue.offset    || var->transp.offset   ||
269 		    var->red.length     || var->green.length    ||
270 		    var->blue.length    || var->transp.length   ||
271 		    var->red.msb_right  || var->green.msb_right ||
272 		    var->blue.msb_right || var->transp.msb_right)
273 			return -EINVAL;
274 	}
275 
276 	if (!info->fbops->fb_check_var) {
277 		*var = info->var;
278 		return 0;
279 	}
280 
281 	/* bitfill_aligned() assumes that it's at least 8x8 */
282 	if (var->xres < 8 || var->yres < 8)
283 		return -EINVAL;
284 
285 	/* Too huge resolution causes multiplication overflow. */
286 	if (check_mul_overflow(var->xres, var->yres, &unused) ||
287 	    check_mul_overflow(var->xres_virtual, var->yres_virtual, &unused))
288 		return -EINVAL;
289 
290 	ret = info->fbops->fb_check_var(var, info);
291 
292 	if (ret)
293 		return ret;
294 
295 	/* verify that virtual resolution >= physical resolution */
296 	if (var->xres_virtual < var->xres ||
297 	    var->yres_virtual < var->yres) {
298 		pr_warn("WARNING: fbcon: Driver '%s' missed to adjust virtual screen size (%ux%u vs. %ux%u)\n",
299 			info->fix.id,
300 			var->xres_virtual, var->yres_virtual,
301 			var->xres, var->yres);
302 		return -EINVAL;
303 	}
304 
305 	if ((var->activate & FB_ACTIVATE_MASK) != FB_ACTIVATE_NOW)
306 		return 0;
307 
308 	if (info->fbops->fb_get_caps) {
309 		ret = fb_check_caps(info, var, activate);
310 
311 		if (ret)
312 			return ret;
313 	}
314 
315 	old_var = info->var;
316 	info->var = *var;
317 
318 	if (info->fbops->fb_set_par) {
319 		ret = info->fbops->fb_set_par(info);
320 
321 		if (ret) {
322 			info->var = old_var;
323 			printk(KERN_WARNING "detected "
324 				"fb_set_par error, "
325 				"error code: %d\n", ret);
326 			return ret;
327 		}
328 	}
329 
330 	fb_pan_display(info, &info->var);
331 	fb_set_cmap(&info->cmap, info);
332 	fb_var_to_videomode(&mode, &info->var);
333 
334 	if (info->modelist.prev && info->modelist.next &&
335 	    !list_empty(&info->modelist))
336 		ret = fb_add_videomode(&mode, &info->modelist);
337 
338 	if (ret) {
339 		info->var = old_var;
340 		return ret;
341 	}
342 
343 	fb_lcd_notify_mode_change(info, &mode);
344 
345 	return 0;
346 }
347 EXPORT_SYMBOL(fb_set_var);
348 
349 static void fb_lcd_notify_blank(struct fb_info *info)
350 {
351 	int power;
352 
353 	switch (info->blank) {
354 	case FB_BLANK_UNBLANK:
355 		power = LCD_POWER_ON;
356 		break;
357 	/* deprecated; TODO: should become 'off' */
358 	case FB_BLANK_NORMAL:
359 		power = LCD_POWER_REDUCED;
360 		break;
361 	case FB_BLANK_VSYNC_SUSPEND:
362 		power = LCD_POWER_REDUCED_VSYNC_SUSPEND;
363 		break;
364 	/* 'off' */
365 	case FB_BLANK_HSYNC_SUSPEND:
366 	case FB_BLANK_POWERDOWN:
367 	default:
368 		power = LCD_POWER_OFF;
369 		break;
370 	}
371 
372 	lcd_notify_blank_all(info->device, power);
373 }
374 
375 static void fb_ledtrig_backlight_notify_blank(struct fb_info *info)
376 {
377 	if (info->blank == FB_BLANK_UNBLANK)
378 		ledtrig_backlight_blank(false);
379 	else
380 		ledtrig_backlight_blank(true);
381 }
382 
383 int fb_blank(struct fb_info *info, int blank)
384 {
385 	int old_blank = info->blank;
386 	int ret;
387 
388 	if (!info->fbops->fb_blank)
389 		return -EINVAL;
390 
391 	if (blank > FB_BLANK_POWERDOWN)
392 		blank = FB_BLANK_POWERDOWN;
393 
394 	info->blank = blank;
395 
396 	ret = info->fbops->fb_blank(blank, info);
397 	if (ret)
398 		goto err;
399 
400 	fb_bl_notify_blank(info, old_blank);
401 	fb_lcd_notify_blank(info);
402 	fb_ledtrig_backlight_notify_blank(info);
403 
404 	return 0;
405 
406 err:
407 	info->blank = old_blank;
408 	return ret;
409 }
410 EXPORT_SYMBOL(fb_blank);
411 
412 static int fb_check_foreignness(struct fb_info *fi)
413 {
414 	const bool foreign_endian = fi->flags & FBINFO_FOREIGN_ENDIAN;
415 
416 	fi->flags &= ~FBINFO_FOREIGN_ENDIAN;
417 
418 #ifdef __BIG_ENDIAN
419 	fi->flags |= foreign_endian ? 0 : FBINFO_BE_MATH;
420 #else
421 	fi->flags |= foreign_endian ? FBINFO_BE_MATH : 0;
422 #endif /* __BIG_ENDIAN */
423 
424 	if (fi->flags & FBINFO_BE_MATH && !fb_be_math(fi)) {
425 		pr_err("%s: enable CONFIG_FB_BIG_ENDIAN to "
426 		       "support this framebuffer\n", fi->fix.id);
427 		return -ENOSYS;
428 	} else if (!(fi->flags & FBINFO_BE_MATH) && fb_be_math(fi)) {
429 		pr_err("%s: enable CONFIG_FB_LITTLE_ENDIAN to "
430 		       "support this framebuffer\n", fi->fix.id);
431 		return -ENOSYS;
432 	}
433 
434 	return 0;
435 }
436 
437 static int do_register_framebuffer(struct fb_info *fb_info)
438 {
439 	int i, err = 0;
440 	struct fb_videomode mode;
441 
442 	if (fb_check_foreignness(fb_info))
443 		return -ENOSYS;
444 
445 	if (num_registered_fb == FB_MAX)
446 		return -ENXIO;
447 
448 	for (i = 0 ; i < FB_MAX; i++)
449 		if (!registered_fb[i])
450 			break;
451 
452 	if (!fb_info->modelist.prev || !fb_info->modelist.next)
453 		INIT_LIST_HEAD(&fb_info->modelist);
454 
455 	fb_var_to_videomode(&mode, &fb_info->var);
456 	err = fb_add_videomode(&mode, &fb_info->modelist);
457 	if (err < 0)
458 		return err;
459 
460 	fb_info->node = i;
461 	refcount_set(&fb_info->count, 1);
462 	mutex_init(&fb_info->lock);
463 	mutex_init(&fb_info->mm_lock);
464 
465 	/*
466 	 * With an fb_blank callback present, we assume that the
467 	 * display is blank, so that fb_blank() enables it on the
468 	 * first modeset.
469 	 */
470 	if (fb_info->fbops->fb_blank)
471 		fb_info->blank = FB_BLANK_POWERDOWN;
472 
473 	fb_device_create(fb_info);
474 
475 	if (fb_info->pixmap.addr == NULL) {
476 		fb_info->pixmap.addr = kmalloc(FBPIXMAPSIZE, GFP_KERNEL);
477 		if (fb_info->pixmap.addr) {
478 			fb_info->pixmap.size = FBPIXMAPSIZE;
479 			fb_info->pixmap.buf_align = 1;
480 			fb_info->pixmap.scan_align = 1;
481 			fb_info->pixmap.access_align = 32;
482 			fb_info->pixmap.flags = FB_PIXMAP_DEFAULT;
483 		}
484 	}
485 	fb_info->pixmap.offset = 0;
486 
487 	if (bitmap_empty(fb_info->pixmap.blit_x, FB_MAX_BLIT_WIDTH))
488 		bitmap_fill(fb_info->pixmap.blit_x, FB_MAX_BLIT_WIDTH);
489 
490 	if (bitmap_empty(fb_info->pixmap.blit_y, FB_MAX_BLIT_HEIGHT))
491 		bitmap_fill(fb_info->pixmap.blit_y, FB_MAX_BLIT_HEIGHT);
492 
493 	if (fb_info->skip_vt_switch)
494 		pm_vt_switch_required(fb_info->device, false);
495 	else
496 		pm_vt_switch_required(fb_info->device, true);
497 
498 	num_registered_fb++;
499 	registered_fb[i] = fb_info;
500 
501 #ifdef CONFIG_GUMSTIX_AM200EPD
502 	{
503 		struct fb_event event;
504 		event.info = fb_info;
505 		fb_notifier_call_chain(FB_EVENT_FB_REGISTERED, &event);
506 	}
507 #endif
508 
509 	return fbcon_fb_registered(fb_info);
510 }
511 
512 static void unbind_console(struct fb_info *fb_info)
513 {
514 	int i = fb_info->node;
515 
516 	if (WARN_ON(i < 0 || i >= FB_MAX || registered_fb[i] != fb_info))
517 		return;
518 
519 	fbcon_fb_unbind(fb_info);
520 }
521 
522 static void unlink_framebuffer(struct fb_info *fb_info)
523 {
524 	int i;
525 
526 	i = fb_info->node;
527 	if (WARN_ON(i < 0 || i >= FB_MAX || registered_fb[i] != fb_info))
528 		return;
529 
530 	fb_device_destroy(fb_info);
531 	pm_vt_switch_unregister(fb_info->device);
532 	unbind_console(fb_info);
533 }
534 
535 static void do_unregister_framebuffer(struct fb_info *fb_info)
536 {
537 	unlink_framebuffer(fb_info);
538 	if (fb_info->pixmap.addr &&
539 	    (fb_info->pixmap.flags & FB_PIXMAP_DEFAULT)) {
540 		kfree(fb_info->pixmap.addr);
541 		fb_info->pixmap.addr = NULL;
542 	}
543 
544 	fb_destroy_modelist(&fb_info->modelist);
545 	registered_fb[fb_info->node] = NULL;
546 	num_registered_fb--;
547 #ifdef CONFIG_GUMSTIX_AM200EPD
548 	{
549 		struct fb_event event;
550 		event.info = fb_info;
551 		fb_notifier_call_chain(FB_EVENT_FB_UNREGISTERED, &event);
552 	}
553 #endif
554 	fbcon_fb_unregistered(fb_info);
555 
556 	/* this may free fb info */
557 	put_fb_info(fb_info);
558 }
559 
560 /**
561  *	register_framebuffer - registers a frame buffer device
562  *	@fb_info: frame buffer info structure
563  *
564  *	Registers a frame buffer device @fb_info.
565  *
566  *	Returns negative errno on error, or zero for success.
567  *
568  */
569 int
570 register_framebuffer(struct fb_info *fb_info)
571 {
572 	int ret;
573 
574 	mutex_lock(&registration_lock);
575 	ret = do_register_framebuffer(fb_info);
576 	mutex_unlock(&registration_lock);
577 
578 	return ret;
579 }
580 EXPORT_SYMBOL(register_framebuffer);
581 
582 /**
583  *	unregister_framebuffer - releases a frame buffer device
584  *	@fb_info: frame buffer info structure
585  *
586  *	Unregisters a frame buffer device @fb_info.
587  *
588  *	Returns negative errno on error, or zero for success.
589  *
590  *      This function will also notify the framebuffer console
591  *      to release the driver.
592  *
593  *      This is meant to be called within a driver's module_exit()
594  *      function. If this is called outside module_exit(), ensure
595  *      that the driver implements fb_open() and fb_release() to
596  *      check that no processes are using the device.
597  */
598 void
599 unregister_framebuffer(struct fb_info *fb_info)
600 {
601 	mutex_lock(&registration_lock);
602 	do_unregister_framebuffer(fb_info);
603 	mutex_unlock(&registration_lock);
604 }
605 EXPORT_SYMBOL(unregister_framebuffer);
606 
607 static void devm_unregister_framebuffer(void *data)
608 {
609 	struct fb_info *info = data;
610 
611 	unregister_framebuffer(info);
612 }
613 
614 /**
615  *	devm_register_framebuffer - resource-managed frame buffer device registration
616  *	@dev: device the framebuffer belongs to
617  *	@fb_info: frame buffer info structure
618  *
619  *	Registers a frame buffer device @fb_info to device @dev.
620  *
621  *	Returns negative errno on error, or zero for success.
622  *
623  */
624 int
625 devm_register_framebuffer(struct device *dev, struct fb_info *fb_info)
626 {
627 	int ret;
628 
629 	ret = register_framebuffer(fb_info);
630 	if (ret)
631 		return ret;
632 
633 	return devm_add_action_or_reset(dev, devm_unregister_framebuffer, fb_info);
634 }
635 EXPORT_SYMBOL(devm_register_framebuffer);
636 
637 /**
638  *	fb_set_suspend - low level driver signals suspend
639  *	@info: framebuffer affected
640  *	@state: 0 = resuming, !=0 = suspending
641  *
642  *	This is meant to be used by low level drivers to
643  * 	signal suspend/resume to the core & clients.
644  *	It must be called with the console semaphore held
645  */
646 void fb_set_suspend(struct fb_info *info, int state)
647 {
648 	WARN_CONSOLE_UNLOCKED();
649 
650 	if (state) {
651 		fbcon_suspended(info);
652 		info->state = FBINFO_STATE_SUSPENDED;
653 	} else {
654 		info->state = FBINFO_STATE_RUNNING;
655 		fbcon_resumed(info);
656 	}
657 }
658 EXPORT_SYMBOL(fb_set_suspend);
659 
660 static int __init fbmem_init(void)
661 {
662 	int ret;
663 
664 	fb_class = class_create("graphics");
665 	if (IS_ERR(fb_class)) {
666 		ret = PTR_ERR(fb_class);
667 		pr_err("Unable to create fb class; errno = %d\n", ret);
668 		goto err_fb_class;
669 	}
670 
671 	ret = fb_init_procfs();
672 	if (ret)
673 		goto err_class_destroy;
674 
675 	ret = fb_register_chrdev();
676 	if (ret)
677 		goto err_fb_cleanup_procfs;
678 
679 	fb_console_init();
680 
681 	return 0;
682 
683 err_fb_cleanup_procfs:
684 	fb_cleanup_procfs();
685 err_class_destroy:
686 	class_destroy(fb_class);
687 err_fb_class:
688 	fb_class = NULL;
689 	return ret;
690 }
691 
692 #ifdef MODULE
693 static void __exit fbmem_exit(void)
694 {
695 	fb_console_exit();
696 	fb_unregister_chrdev();
697 	fb_cleanup_procfs();
698 	class_destroy(fb_class);
699 }
700 
701 module_init(fbmem_init);
702 module_exit(fbmem_exit);
703 MODULE_LICENSE("GPL");
704 MODULE_DESCRIPTION("Framebuffer base");
705 #else
706 subsys_initcall(fbmem_init);
707 #endif
708 
709 int fb_new_modelist(struct fb_info *info)
710 {
711 	struct fb_var_screeninfo var = info->var;
712 	struct list_head *pos, *n;
713 	struct fb_modelist *modelist;
714 	struct fb_videomode *m, mode;
715 	int err;
716 
717 	list_for_each_safe(pos, n, &info->modelist) {
718 		modelist = list_entry(pos, struct fb_modelist, list);
719 		m = &modelist->mode;
720 		fb_videomode_to_var(&var, m);
721 		var.activate = FB_ACTIVATE_TEST;
722 		err = fb_set_var(info, &var);
723 		fb_var_to_videomode(&mode, &var);
724 		if (err || !fb_mode_is_equal(m, &mode)) {
725 			list_del(pos);
726 			kfree(pos);
727 		}
728 	}
729 
730 	if (list_empty(&info->modelist))
731 		return 1;
732 
733 	fbcon_new_modelist(info);
734 
735 	return 0;
736 }
737 
738 bool fb_modesetting_disabled(const char *drvname)
739 {
740 	bool fwonly = video_firmware_drivers_only();
741 
742 	if (fwonly)
743 		pr_warn("Driver %s not loading because of nomodeset parameter\n",
744 			drvname);
745 
746 	return fwonly;
747 }
748 EXPORT_SYMBOL(fb_modesetting_disabled);
749 
750 MODULE_LICENSE("GPL");
751