2 * Copyright (c) 2006-2009 Red Hat Inc.
3 * Copyright (c) 2006-2008 Intel Corporation
4 * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
6 * DRM framebuffer helper functions
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.
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
27 * Dave Airlie <airlied@linux.ie>
28 * Jesse Barnes <jesse.barnes@intel.com>
30 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
32 #include <linux/kernel.h>
33 #include <linux/sysrq.h>
34 #include <linux/slab.h>
36 #include <linux/module.h>
38 #include <drm/drm_crtc.h>
39 #include <drm/drm_fb_helper.h>
40 #include <drm/drm_crtc_helper.h>
42 MODULE_AUTHOR("David Airlie, Jesse Barnes");
43 MODULE_DESCRIPTION("DRM KMS helper");
44 MODULE_LICENSE("GPL and additional rights");
46 static LIST_HEAD(kernel_fb_helper_list);
51 * The fb helper functions are useful to provide an fbdev on top of a drm kernel
52 * mode setting driver. They can be used mostly independantely from the crtc
53 * helper functions used by many drivers to implement the kernel mode setting
56 * Initialization is done as a three-step process with drm_fb_helper_init(),
57 * drm_fb_helper_single_add_all_connectors() and drm_fb_helper_initial_config().
58 * Drivers with fancier requirements than the default beheviour can override the
59 * second step with their own code. Teardown is done with drm_fb_helper_fini().
61 * At runtime drivers should restore the fbdev console by calling
62 * drm_fb_helper_restore_fbdev_mode() from their ->lastclose callback. They
63 * should also notify the fb helper code from updates to the output
64 * configuration by calling drm_fb_helper_hotplug_event(). For easier
65 * integration with the output polling code in drm_crtc_helper.c the modeset
66 * code proves a ->output_poll_changed callback.
68 * All other functions exported by the fb helper library can be used to
69 * implement the fbdev driver interface by the driver.
73 * drm_fb_helper_single_add_all_connectors() - add all connectors to fbdev
75 * @fb_helper: fbdev initialized with drm_fb_helper_init
77 * This functions adds all the available connectors for use with the given
78 * fb_helper. This is a separate step to allow drivers to freely assign
79 * connectors to the fbdev, e.g. if some are reserved for special purposes or
80 * not adequate to be used for the fbcon.
82 * Since this is part of the initial setup before the fbdev is published, no
83 * locking is required.
85 int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
87 struct drm_device *dev = fb_helper->dev;
88 struct drm_connector *connector;
91 list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
92 struct drm_fb_helper_connector *fb_helper_connector;
94 fb_helper_connector = kzalloc(sizeof(struct drm_fb_helper_connector), GFP_KERNEL);
95 if (!fb_helper_connector)
98 fb_helper_connector->connector = connector;
99 fb_helper->connector_info[fb_helper->connector_count++] = fb_helper_connector;
103 for (i = 0; i < fb_helper->connector_count; i++) {
104 kfree(fb_helper->connector_info[i]);
105 fb_helper->connector_info[i] = NULL;
107 fb_helper->connector_count = 0;
110 EXPORT_SYMBOL(drm_fb_helper_single_add_all_connectors);
112 static int drm_fb_helper_parse_command_line(struct drm_fb_helper *fb_helper)
114 struct drm_fb_helper_connector *fb_helper_conn;
117 for (i = 0; i < fb_helper->connector_count; i++) {
118 struct drm_cmdline_mode *mode;
119 struct drm_connector *connector;
122 fb_helper_conn = fb_helper->connector_info[i];
123 connector = fb_helper_conn->connector;
124 mode = &fb_helper_conn->cmdline_mode;
126 /* do something on return - turn off connector maybe */
127 if (fb_get_options(drm_get_connector_name(connector), &option))
130 if (drm_mode_parse_command_line_for_connector(option,
135 switch (mode->force) {
139 case DRM_FORCE_ON_DIGITAL:
148 DRM_INFO("forcing %s connector %s\n",
149 drm_get_connector_name(connector), s);
150 connector->force = mode->force;
153 DRM_DEBUG_KMS("cmdline mode for connector %s %dx%d@%dHz%s%s%s\n",
154 drm_get_connector_name(connector),
155 mode->xres, mode->yres,
156 mode->refresh_specified ? mode->refresh : 60,
157 mode->rb ? " reduced blanking" : "",
158 mode->margins ? " with margins" : "",
159 mode->interlace ? " interlaced" : "");
166 static void drm_fb_helper_save_lut_atomic(struct drm_crtc *crtc, struct drm_fb_helper *helper)
168 uint16_t *r_base, *g_base, *b_base;
171 if (helper->funcs->gamma_get == NULL)
174 r_base = crtc->gamma_store;
175 g_base = r_base + crtc->gamma_size;
176 b_base = g_base + crtc->gamma_size;
178 for (i = 0; i < crtc->gamma_size; i++)
179 helper->funcs->gamma_get(crtc, &r_base[i], &g_base[i], &b_base[i], i);
182 static void drm_fb_helper_restore_lut_atomic(struct drm_crtc *crtc)
184 uint16_t *r_base, *g_base, *b_base;
186 if (crtc->funcs->gamma_set == NULL)
189 r_base = crtc->gamma_store;
190 g_base = r_base + crtc->gamma_size;
191 b_base = g_base + crtc->gamma_size;
193 crtc->funcs->gamma_set(crtc, r_base, g_base, b_base, 0, crtc->gamma_size);
197 * drm_fb_helper_debug_enter - implementation for ->fb_debug_enter
198 * @info: fbdev registered by the helper
200 int drm_fb_helper_debug_enter(struct fb_info *info)
202 struct drm_fb_helper *helper = info->par;
203 struct drm_crtc_helper_funcs *funcs;
206 if (list_empty(&kernel_fb_helper_list))
209 list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
210 for (i = 0; i < helper->crtc_count; i++) {
211 struct drm_mode_set *mode_set =
212 &helper->crtc_info[i].mode_set;
214 if (!mode_set->crtc->enabled)
217 funcs = mode_set->crtc->helper_private;
218 drm_fb_helper_save_lut_atomic(mode_set->crtc, helper);
219 funcs->mode_set_base_atomic(mode_set->crtc,
223 ENTER_ATOMIC_MODE_SET);
229 EXPORT_SYMBOL(drm_fb_helper_debug_enter);
231 /* Find the real fb for a given fb helper CRTC */
232 static struct drm_framebuffer *drm_mode_config_fb(struct drm_crtc *crtc)
234 struct drm_device *dev = crtc->dev;
237 list_for_each_entry(c, &dev->mode_config.crtc_list, head) {
238 if (crtc->base.id == c->base.id)
246 * drm_fb_helper_debug_leave - implementation for ->fb_debug_leave
247 * @info: fbdev registered by the helper
249 int drm_fb_helper_debug_leave(struct fb_info *info)
251 struct drm_fb_helper *helper = info->par;
252 struct drm_crtc *crtc;
253 struct drm_crtc_helper_funcs *funcs;
254 struct drm_framebuffer *fb;
257 for (i = 0; i < helper->crtc_count; i++) {
258 struct drm_mode_set *mode_set = &helper->crtc_info[i].mode_set;
259 crtc = mode_set->crtc;
260 funcs = crtc->helper_private;
261 fb = drm_mode_config_fb(crtc);
267 DRM_ERROR("no fb to restore??\n");
271 drm_fb_helper_restore_lut_atomic(mode_set->crtc);
272 funcs->mode_set_base_atomic(mode_set->crtc, fb, crtc->x,
273 crtc->y, LEAVE_ATOMIC_MODE_SET);
278 EXPORT_SYMBOL(drm_fb_helper_debug_leave);
281 * drm_fb_helper_restore_fbdev_mode - restore fbdev configuration
282 * @fb_helper: fbcon to restore
284 * This should be called from driver's drm ->lastclose callback
285 * when implementing an fbcon on top of kms using this helper. This ensures that
286 * the user isn't greeted with a black screen when e.g. X dies.
288 bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper)
290 struct drm_device *dev = fb_helper->dev;
291 struct drm_plane *plane;
295 drm_warn_on_modeset_not_all_locked(dev);
297 list_for_each_entry(plane, &dev->mode_config.plane_list, head)
298 drm_plane_force_disable(plane);
300 for (i = 0; i < fb_helper->crtc_count; i++) {
301 struct drm_mode_set *mode_set = &fb_helper->crtc_info[i].mode_set;
302 struct drm_crtc *crtc = mode_set->crtc;
305 if (crtc->funcs->cursor_set) {
306 ret = crtc->funcs->cursor_set(crtc, NULL, 0, 0, 0);
311 ret = drm_mode_set_config_internal(mode_set);
317 EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode);
320 * restore fbcon display for all kms driver's using this helper, used for sysrq
321 * and panic handling.
323 static bool drm_fb_helper_force_kernel_mode(void)
325 bool ret, error = false;
326 struct drm_fb_helper *helper;
328 if (list_empty(&kernel_fb_helper_list))
331 list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
332 if (helper->dev->switch_power_state == DRM_SWITCH_POWER_OFF)
335 ret = drm_fb_helper_restore_fbdev_mode(helper);
342 static int drm_fb_helper_panic(struct notifier_block *n, unsigned long ununsed,
346 * It's a waste of time and effort to switch back to text console
347 * if the kernel should reboot before panic messages can be seen.
349 if (panic_timeout < 0)
352 pr_err("panic occurred, switching back to text console\n");
353 return drm_fb_helper_force_kernel_mode();
356 static struct notifier_block paniced = {
357 .notifier_call = drm_fb_helper_panic,
360 static bool drm_fb_helper_is_bound(struct drm_fb_helper *fb_helper)
362 struct drm_device *dev = fb_helper->dev;
363 struct drm_crtc *crtc;
364 int bound = 0, crtcs_bound = 0;
366 list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
369 if (crtc->fb == fb_helper->fb)
373 if (bound < crtcs_bound)
378 #ifdef CONFIG_MAGIC_SYSRQ
379 static void drm_fb_helper_restore_work_fn(struct work_struct *ignored)
382 ret = drm_fb_helper_force_kernel_mode();
384 DRM_ERROR("Failed to restore crtc configuration\n");
386 static DECLARE_WORK(drm_fb_helper_restore_work, drm_fb_helper_restore_work_fn);
388 static void drm_fb_helper_sysrq(int dummy1)
390 schedule_work(&drm_fb_helper_restore_work);
393 static struct sysrq_key_op sysrq_drm_fb_helper_restore_op = {
394 .handler = drm_fb_helper_sysrq,
395 .help_msg = "force-fb(V)",
396 .action_msg = "Restore framebuffer console",
399 static struct sysrq_key_op sysrq_drm_fb_helper_restore_op = { };
402 static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode)
404 struct drm_fb_helper *fb_helper = info->par;
405 struct drm_device *dev = fb_helper->dev;
406 struct drm_crtc *crtc;
407 struct drm_connector *connector;
411 * fbdev->blank can be called from irq context in case of a panic.
412 * Since we already have our own special panic handler which will
413 * restore the fbdev console mode completely, just bail out early.
415 if (oops_in_progress)
419 * fbdev->blank can be called from irq context in case of a panic.
420 * Since we already have our own special panic handler which will
421 * restore the fbdev console mode completely, just bail out early.
423 if (oops_in_progress)
427 * For each CRTC in this fb, turn the connectors on/off.
429 drm_modeset_lock_all(dev);
430 if (!drm_fb_helper_is_bound(fb_helper)) {
431 drm_modeset_unlock_all(dev);
435 for (i = 0; i < fb_helper->crtc_count; i++) {
436 crtc = fb_helper->crtc_info[i].mode_set.crtc;
441 /* Walk the connectors & encoders on this fb turning them on/off */
442 for (j = 0; j < fb_helper->connector_count; j++) {
443 connector = fb_helper->connector_info[j]->connector;
444 connector->funcs->dpms(connector, dpms_mode);
445 drm_object_property_set_value(&connector->base,
446 dev->mode_config.dpms_property, dpms_mode);
449 drm_modeset_unlock_all(dev);
453 * drm_fb_helper_blank - implementation for ->fb_blank
454 * @blank: desired blanking state
455 * @info: fbdev registered by the helper
457 int drm_fb_helper_blank(int blank, struct fb_info *info)
460 /* Display: On; HSync: On, VSync: On */
461 case FB_BLANK_UNBLANK:
462 drm_fb_helper_dpms(info, DRM_MODE_DPMS_ON);
464 /* Display: Off; HSync: On, VSync: On */
465 case FB_BLANK_NORMAL:
466 drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
468 /* Display: Off; HSync: Off, VSync: On */
469 case FB_BLANK_HSYNC_SUSPEND:
470 drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
472 /* Display: Off; HSync: On, VSync: Off */
473 case FB_BLANK_VSYNC_SUSPEND:
474 drm_fb_helper_dpms(info, DRM_MODE_DPMS_SUSPEND);
476 /* Display: Off; HSync: Off, VSync: Off */
477 case FB_BLANK_POWERDOWN:
478 drm_fb_helper_dpms(info, DRM_MODE_DPMS_OFF);
483 EXPORT_SYMBOL(drm_fb_helper_blank);
485 static void drm_fb_helper_crtc_free(struct drm_fb_helper *helper)
489 for (i = 0; i < helper->connector_count; i++)
490 kfree(helper->connector_info[i]);
491 kfree(helper->connector_info);
492 for (i = 0; i < helper->crtc_count; i++) {
493 kfree(helper->crtc_info[i].mode_set.connectors);
494 if (helper->crtc_info[i].mode_set.mode)
495 drm_mode_destroy(helper->dev, helper->crtc_info[i].mode_set.mode);
497 kfree(helper->crtc_info);
501 * drm_fb_helper_init - initialize a drm_fb_helper structure
503 * @fb_helper: driver-allocated fbdev helper structure to initialize
504 * @crtc_count: maximum number of crtcs to support in this fbdev emulation
505 * @max_conn_count: max connector count
507 * This allocates the structures for the fbdev helper with the given limits.
508 * Note that this won't yet touch the hardware (through the driver interfaces)
509 * nor register the fbdev. This is only done in drm_fb_helper_initial_config()
510 * to allow driver writes more control over the exact init sequence.
512 * Drivers must set fb_helper->funcs before calling
513 * drm_fb_helper_initial_config().
516 * Zero if everything went ok, nonzero otherwise.
518 int drm_fb_helper_init(struct drm_device *dev,
519 struct drm_fb_helper *fb_helper,
520 int crtc_count, int max_conn_count)
522 struct drm_crtc *crtc;
525 fb_helper->dev = dev;
527 INIT_LIST_HEAD(&fb_helper->kernel_fb_list);
529 fb_helper->crtc_info = kcalloc(crtc_count, sizeof(struct drm_fb_helper_crtc), GFP_KERNEL);
530 if (!fb_helper->crtc_info)
533 fb_helper->crtc_count = crtc_count;
534 fb_helper->connector_info = kcalloc(dev->mode_config.num_connector, sizeof(struct drm_fb_helper_connector *), GFP_KERNEL);
535 if (!fb_helper->connector_info) {
536 kfree(fb_helper->crtc_info);
539 fb_helper->connector_count = 0;
541 for (i = 0; i < crtc_count; i++) {
542 fb_helper->crtc_info[i].mode_set.connectors =
543 kcalloc(max_conn_count,
544 sizeof(struct drm_connector *),
547 if (!fb_helper->crtc_info[i].mode_set.connectors)
549 fb_helper->crtc_info[i].mode_set.num_connectors = 0;
553 list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
554 fb_helper->crtc_info[i].mode_set.crtc = crtc;
560 drm_fb_helper_crtc_free(fb_helper);
563 EXPORT_SYMBOL(drm_fb_helper_init);
565 void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
567 if (!list_empty(&fb_helper->kernel_fb_list)) {
568 list_del(&fb_helper->kernel_fb_list);
569 if (list_empty(&kernel_fb_helper_list)) {
570 pr_info("drm: unregistered panic notifier\n");
571 atomic_notifier_chain_unregister(&panic_notifier_list,
573 unregister_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
577 drm_fb_helper_crtc_free(fb_helper);
580 EXPORT_SYMBOL(drm_fb_helper_fini);
582 static int setcolreg(struct drm_crtc *crtc, u16 red, u16 green,
583 u16 blue, u16 regno, struct fb_info *info)
585 struct drm_fb_helper *fb_helper = info->par;
586 struct drm_framebuffer *fb = fb_helper->fb;
589 if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
592 /* place color in psuedopalette */
595 palette = (u32 *)info->pseudo_palette;
596 red >>= (16 - info->var.red.length);
597 green >>= (16 - info->var.green.length);
598 blue >>= (16 - info->var.blue.length);
599 value = (red << info->var.red.offset) |
600 (green << info->var.green.offset) |
601 (blue << info->var.blue.offset);
602 if (info->var.transp.length > 0) {
603 u32 mask = (1 << info->var.transp.length) - 1;
604 mask <<= info->var.transp.offset;
607 palette[regno] = value;
612 * The driver really shouldn't advertise pseudo/directcolor
613 * visuals if it can't deal with the palette.
615 if (WARN_ON(!fb_helper->funcs->gamma_set ||
616 !fb_helper->funcs->gamma_get))
621 if (fb->bits_per_pixel == 16) {
624 if (fb->depth == 16 && regno > 63)
626 if (fb->depth == 15 && regno > 31)
629 if (fb->depth == 16) {
633 for (i = 0; i < 8; i++)
634 fb_helper->funcs->gamma_set(crtc, red,
635 green, blue, pindex + i);
638 fb_helper->funcs->gamma_get(crtc, &r,
642 for (i = 0; i < 4; i++)
643 fb_helper->funcs->gamma_set(crtc, r,
650 fb_helper->funcs->gamma_set(crtc, red, green, blue, pindex);
655 * drm_fb_helper_setcmap - implementation for ->fb_setcmap
657 * @info: fbdev registered by the helper
659 int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
661 struct drm_fb_helper *fb_helper = info->par;
662 struct drm_device *dev = fb_helper->dev;
663 struct drm_crtc_helper_funcs *crtc_funcs;
664 u16 *red, *green, *blue, *transp;
665 struct drm_crtc *crtc;
669 drm_modeset_lock_all(dev);
670 if (!drm_fb_helper_is_bound(fb_helper)) {
671 drm_modeset_unlock_all(dev);
675 for (i = 0; i < fb_helper->crtc_count; i++) {
676 crtc = fb_helper->crtc_info[i].mode_set.crtc;
677 crtc_funcs = crtc->helper_private;
682 transp = cmap->transp;
685 for (j = 0; j < cmap->len; j++) {
686 u16 hred, hgreen, hblue, htransp = 0xffff;
695 rc = setcolreg(crtc, hred, hgreen, hblue, start++, info);
699 if (crtc_funcs->load_lut)
700 crtc_funcs->load_lut(crtc);
703 drm_modeset_unlock_all(dev);
706 EXPORT_SYMBOL(drm_fb_helper_setcmap);
709 * drm_fb_helper_check_var - implementation for ->fb_check_var
710 * @var: screeninfo to check
711 * @info: fbdev registered by the helper
713 int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
714 struct fb_info *info)
716 struct drm_fb_helper *fb_helper = info->par;
717 struct drm_framebuffer *fb = fb_helper->fb;
720 if (var->pixclock != 0 || in_dbg_master())
723 /* Need to resize the fb object !!! */
724 if (var->bits_per_pixel > fb->bits_per_pixel ||
725 var->xres > fb->width || var->yres > fb->height ||
726 var->xres_virtual > fb->width || var->yres_virtual > fb->height) {
727 DRM_DEBUG("fb userspace requested width/height/bpp is greater than current fb "
728 "request %dx%d-%d (virtual %dx%d) > %dx%d-%d\n",
729 var->xres, var->yres, var->bits_per_pixel,
730 var->xres_virtual, var->yres_virtual,
731 fb->width, fb->height, fb->bits_per_pixel);
735 switch (var->bits_per_pixel) {
737 depth = (var->green.length == 6) ? 16 : 15;
740 depth = (var->transp.length > 0) ? 32 : 24;
743 depth = var->bits_per_pixel;
750 var->green.offset = 0;
751 var->blue.offset = 0;
753 var->green.length = 8;
754 var->blue.length = 8;
755 var->transp.length = 0;
756 var->transp.offset = 0;
759 var->red.offset = 10;
760 var->green.offset = 5;
761 var->blue.offset = 0;
763 var->green.length = 5;
764 var->blue.length = 5;
765 var->transp.length = 1;
766 var->transp.offset = 15;
769 var->red.offset = 11;
770 var->green.offset = 5;
771 var->blue.offset = 0;
773 var->green.length = 6;
774 var->blue.length = 5;
775 var->transp.length = 0;
776 var->transp.offset = 0;
779 var->red.offset = 16;
780 var->green.offset = 8;
781 var->blue.offset = 0;
783 var->green.length = 8;
784 var->blue.length = 8;
785 var->transp.length = 0;
786 var->transp.offset = 0;
789 var->red.offset = 16;
790 var->green.offset = 8;
791 var->blue.offset = 0;
793 var->green.length = 8;
794 var->blue.length = 8;
795 var->transp.length = 8;
796 var->transp.offset = 24;
803 EXPORT_SYMBOL(drm_fb_helper_check_var);
806 * drm_fb_helper_set_par - implementation for ->fb_set_par
807 * @info: fbdev registered by the helper
809 * This will let fbcon do the mode init and is called at initialization time by
810 * the fbdev core when registering the driver, and later on through the hotplug
813 int drm_fb_helper_set_par(struct fb_info *info)
815 struct drm_fb_helper *fb_helper = info->par;
816 struct drm_device *dev = fb_helper->dev;
817 struct fb_var_screeninfo *var = &info->var;
821 if (var->pixclock != 0) {
822 DRM_ERROR("PIXEL CLOCK SET\n");
826 drm_modeset_lock_all(dev);
827 for (i = 0; i < fb_helper->crtc_count; i++) {
828 ret = drm_mode_set_config_internal(&fb_helper->crtc_info[i].mode_set);
830 drm_modeset_unlock_all(dev);
834 drm_modeset_unlock_all(dev);
836 if (fb_helper->delayed_hotplug) {
837 fb_helper->delayed_hotplug = false;
838 drm_fb_helper_hotplug_event(fb_helper);
842 EXPORT_SYMBOL(drm_fb_helper_set_par);
845 * drm_fb_helper_pan_display - implementation for ->fb_pan_display
846 * @var: updated screen information
847 * @info: fbdev registered by the helper
849 int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
850 struct fb_info *info)
852 struct drm_fb_helper *fb_helper = info->par;
853 struct drm_device *dev = fb_helper->dev;
854 struct drm_mode_set *modeset;
855 struct drm_crtc *crtc;
859 drm_modeset_lock_all(dev);
860 if (!drm_fb_helper_is_bound(fb_helper)) {
861 drm_modeset_unlock_all(dev);
865 for (i = 0; i < fb_helper->crtc_count; i++) {
866 crtc = fb_helper->crtc_info[i].mode_set.crtc;
868 modeset = &fb_helper->crtc_info[i].mode_set;
870 modeset->x = var->xoffset;
871 modeset->y = var->yoffset;
873 if (modeset->num_connectors) {
874 ret = drm_mode_set_config_internal(modeset);
876 info->var.xoffset = var->xoffset;
877 info->var.yoffset = var->yoffset;
881 drm_modeset_unlock_all(dev);
884 EXPORT_SYMBOL(drm_fb_helper_pan_display);
887 * Allocates the backing storage and sets up the fbdev info structure through
888 * the ->fb_probe callback and then registers the fbdev and sets up the panic
891 static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
897 struct fb_info *info;
898 struct drm_fb_helper_surface_size sizes;
901 memset(&sizes, 0, sizeof(struct drm_fb_helper_surface_size));
902 sizes.surface_depth = 24;
903 sizes.surface_bpp = 32;
904 sizes.fb_width = (unsigned)-1;
905 sizes.fb_height = (unsigned)-1;
907 /* if driver picks 8 or 16 by default use that
908 for both depth/bpp */
909 if (preferred_bpp != sizes.surface_bpp)
910 sizes.surface_depth = sizes.surface_bpp = preferred_bpp;
912 /* first up get a count of crtcs now in use and new min/maxes width/heights */
913 for (i = 0; i < fb_helper->connector_count; i++) {
914 struct drm_fb_helper_connector *fb_helper_conn = fb_helper->connector_info[i];
915 struct drm_cmdline_mode *cmdline_mode;
917 cmdline_mode = &fb_helper_conn->cmdline_mode;
919 if (cmdline_mode->bpp_specified) {
920 switch (cmdline_mode->bpp) {
922 sizes.surface_depth = sizes.surface_bpp = 8;
925 sizes.surface_depth = 15;
926 sizes.surface_bpp = 16;
929 sizes.surface_depth = sizes.surface_bpp = 16;
932 sizes.surface_depth = sizes.surface_bpp = 24;
935 sizes.surface_depth = 24;
936 sizes.surface_bpp = 32;
944 for (i = 0; i < fb_helper->crtc_count; i++) {
945 struct drm_display_mode *desired_mode;
946 desired_mode = fb_helper->crtc_info[i].desired_mode;
950 gamma_size = fb_helper->crtc_info[i].mode_set.crtc->gamma_size;
951 if (desired_mode->hdisplay < sizes.fb_width)
952 sizes.fb_width = desired_mode->hdisplay;
953 if (desired_mode->vdisplay < sizes.fb_height)
954 sizes.fb_height = desired_mode->vdisplay;
955 if (desired_mode->hdisplay > sizes.surface_width)
956 sizes.surface_width = desired_mode->hdisplay;
957 if (desired_mode->vdisplay > sizes.surface_height)
958 sizes.surface_height = desired_mode->vdisplay;
963 if (crtc_count == 0 || sizes.fb_width == -1 || sizes.fb_height == -1) {
964 /* hmm everyone went away - assume VGA cable just fell out
965 and will come back later. */
966 DRM_INFO("Cannot find any crtc or sizes - going 1024x768\n");
967 sizes.fb_width = sizes.surface_width = 1024;
968 sizes.fb_height = sizes.surface_height = 768;
971 /* push down into drivers */
972 ret = (*fb_helper->funcs->fb_probe)(fb_helper, &sizes);
976 info = fb_helper->fbdev;
979 * Set the fb pointer - usually drm_setup_crtcs does this for hotplug
980 * events, but at init time drm_setup_crtcs needs to be called before
981 * the fb is allocated (since we need to figure out the desired size of
982 * the fb before we can allocate it ...). Hence we need to fix things up
985 for (i = 0; i < fb_helper->crtc_count; i++)
986 if (fb_helper->crtc_info[i].mode_set.num_connectors)
987 fb_helper->crtc_info[i].mode_set.fb = fb_helper->fb;
990 info->var.pixclock = 0;
991 if (register_framebuffer(info) < 0)
994 dev_info(fb_helper->dev->dev, "fb%d: %s frame buffer device\n",
995 info->node, info->fix.id);
997 /* Switch back to kernel console on panic */
998 /* multi card linked list maybe */
999 if (list_empty(&kernel_fb_helper_list)) {
1000 dev_info(fb_helper->dev->dev, "registered panic notifier\n");
1001 atomic_notifier_chain_register(&panic_notifier_list,
1003 register_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
1006 list_add(&fb_helper->kernel_fb_list, &kernel_fb_helper_list);
1012 * drm_fb_helper_fill_fix - initializes fixed fbdev information
1013 * @info: fbdev registered by the helper
1014 * @pitch: desired pitch
1015 * @depth: desired depth
1017 * Helper to fill in the fixed fbdev information useful for a non-accelerated
1018 * fbdev emulations. Drivers which support acceleration methods which impose
1019 * additional constraints need to set up their own limits.
1021 * Drivers should call this (or their equivalent setup code) from their
1022 * ->fb_probe callback.
1024 void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
1027 info->fix.type = FB_TYPE_PACKED_PIXELS;
1028 info->fix.visual = depth == 8 ? FB_VISUAL_PSEUDOCOLOR :
1029 FB_VISUAL_TRUECOLOR;
1030 info->fix.mmio_start = 0;
1031 info->fix.mmio_len = 0;
1032 info->fix.type_aux = 0;
1033 info->fix.xpanstep = 1; /* doing it in hw */
1034 info->fix.ypanstep = 1; /* doing it in hw */
1035 info->fix.ywrapstep = 0;
1036 info->fix.accel = FB_ACCEL_NONE;
1037 info->fix.type_aux = 0;
1039 info->fix.line_length = pitch;
1042 EXPORT_SYMBOL(drm_fb_helper_fill_fix);
1045 * drm_fb_helper_fill_var - initalizes variable fbdev information
1046 * @info: fbdev instance to set up
1047 * @fb_helper: fb helper instance to use as template
1048 * @fb_width: desired fb width
1049 * @fb_height: desired fb height
1051 * Sets up the variable fbdev metainformation from the given fb helper instance
1052 * and the drm framebuffer allocated in fb_helper->fb.
1054 * Drivers should call this (or their equivalent setup code) from their
1055 * ->fb_probe callback after having allocated the fbdev backing
1056 * storage framebuffer.
1058 void drm_fb_helper_fill_var(struct fb_info *info, struct drm_fb_helper *fb_helper,
1059 uint32_t fb_width, uint32_t fb_height)
1061 struct drm_framebuffer *fb = fb_helper->fb;
1062 info->pseudo_palette = fb_helper->pseudo_palette;
1063 info->var.xres_virtual = fb->width;
1064 info->var.yres_virtual = fb->height;
1065 info->var.bits_per_pixel = fb->bits_per_pixel;
1066 info->var.accel_flags = FB_ACCELF_TEXT;
1067 info->var.xoffset = 0;
1068 info->var.yoffset = 0;
1069 info->var.activate = FB_ACTIVATE_NOW;
1070 info->var.height = -1;
1071 info->var.width = -1;
1073 switch (fb->depth) {
1075 info->var.red.offset = 0;
1076 info->var.green.offset = 0;
1077 info->var.blue.offset = 0;
1078 info->var.red.length = 8; /* 8bit DAC */
1079 info->var.green.length = 8;
1080 info->var.blue.length = 8;
1081 info->var.transp.offset = 0;
1082 info->var.transp.length = 0;
1085 info->var.red.offset = 10;
1086 info->var.green.offset = 5;
1087 info->var.blue.offset = 0;
1088 info->var.red.length = 5;
1089 info->var.green.length = 5;
1090 info->var.blue.length = 5;
1091 info->var.transp.offset = 15;
1092 info->var.transp.length = 1;
1095 info->var.red.offset = 11;
1096 info->var.green.offset = 5;
1097 info->var.blue.offset = 0;
1098 info->var.red.length = 5;
1099 info->var.green.length = 6;
1100 info->var.blue.length = 5;
1101 info->var.transp.offset = 0;
1104 info->var.red.offset = 16;
1105 info->var.green.offset = 8;
1106 info->var.blue.offset = 0;
1107 info->var.red.length = 8;
1108 info->var.green.length = 8;
1109 info->var.blue.length = 8;
1110 info->var.transp.offset = 0;
1111 info->var.transp.length = 0;
1114 info->var.red.offset = 16;
1115 info->var.green.offset = 8;
1116 info->var.blue.offset = 0;
1117 info->var.red.length = 8;
1118 info->var.green.length = 8;
1119 info->var.blue.length = 8;
1120 info->var.transp.offset = 24;
1121 info->var.transp.length = 8;
1127 info->var.xres = fb_width;
1128 info->var.yres = fb_height;
1130 EXPORT_SYMBOL(drm_fb_helper_fill_var);
1132 static int drm_fb_helper_probe_connector_modes(struct drm_fb_helper *fb_helper,
1136 struct drm_connector *connector;
1140 for (i = 0; i < fb_helper->connector_count; i++) {
1141 connector = fb_helper->connector_info[i]->connector;
1142 count += connector->funcs->fill_modes(connector, maxX, maxY);
1148 static struct drm_display_mode *drm_has_preferred_mode(struct drm_fb_helper_connector *fb_connector, int width, int height)
1150 struct drm_display_mode *mode;
1152 list_for_each_entry(mode, &fb_connector->connector->modes, head) {
1153 if (drm_mode_width(mode) > width ||
1154 drm_mode_height(mode) > height)
1156 if (mode->type & DRM_MODE_TYPE_PREFERRED)
1162 static bool drm_has_cmdline_mode(struct drm_fb_helper_connector *fb_connector)
1164 struct drm_cmdline_mode *cmdline_mode;
1165 cmdline_mode = &fb_connector->cmdline_mode;
1166 return cmdline_mode->specified;
1169 static struct drm_display_mode *drm_pick_cmdline_mode(struct drm_fb_helper_connector *fb_helper_conn,
1170 int width, int height)
1172 struct drm_cmdline_mode *cmdline_mode;
1173 struct drm_display_mode *mode = NULL;
1175 cmdline_mode = &fb_helper_conn->cmdline_mode;
1176 if (cmdline_mode->specified == false)
1179 /* attempt to find a matching mode in the list of modes
1180 * we have gotten so far, if not add a CVT mode that conforms
1182 if (cmdline_mode->rb || cmdline_mode->margins)
1185 list_for_each_entry(mode, &fb_helper_conn->connector->modes, head) {
1186 /* check width/height */
1187 if (mode->hdisplay != cmdline_mode->xres ||
1188 mode->vdisplay != cmdline_mode->yres)
1191 if (cmdline_mode->refresh_specified) {
1192 if (mode->vrefresh != cmdline_mode->refresh)
1196 if (cmdline_mode->interlace) {
1197 if (!(mode->flags & DRM_MODE_FLAG_INTERLACE))
1204 mode = drm_mode_create_from_cmdline_mode(fb_helper_conn->connector->dev,
1206 list_add(&mode->head, &fb_helper_conn->connector->modes);
1210 static bool drm_connector_enabled(struct drm_connector *connector, bool strict)
1215 enable = connector->status == connector_status_connected;
1217 enable = connector->status != connector_status_disconnected;
1222 static void drm_enable_connectors(struct drm_fb_helper *fb_helper,
1225 bool any_enabled = false;
1226 struct drm_connector *connector;
1229 for (i = 0; i < fb_helper->connector_count; i++) {
1230 connector = fb_helper->connector_info[i]->connector;
1231 enabled[i] = drm_connector_enabled(connector, true);
1232 DRM_DEBUG_KMS("connector %d enabled? %s\n", connector->base.id,
1233 enabled[i] ? "yes" : "no");
1234 any_enabled |= enabled[i];
1240 for (i = 0; i < fb_helper->connector_count; i++) {
1241 connector = fb_helper->connector_info[i]->connector;
1242 enabled[i] = drm_connector_enabled(connector, false);
1246 static bool drm_target_cloned(struct drm_fb_helper *fb_helper,
1247 struct drm_display_mode **modes,
1248 bool *enabled, int width, int height)
1251 bool can_clone = false;
1252 struct drm_fb_helper_connector *fb_helper_conn;
1253 struct drm_display_mode *dmt_mode, *mode;
1255 /* only contemplate cloning in the single crtc case */
1256 if (fb_helper->crtc_count > 1)
1260 for (i = 0; i < fb_helper->connector_count; i++) {
1265 /* only contemplate cloning if more than one connector is enabled */
1269 /* check the command line or if nothing common pick 1024x768 */
1271 for (i = 0; i < fb_helper->connector_count; i++) {
1274 fb_helper_conn = fb_helper->connector_info[i];
1275 modes[i] = drm_pick_cmdline_mode(fb_helper_conn, width, height);
1280 for (j = 0; j < i; j++) {
1283 if (!drm_mode_equal(modes[j], modes[i]))
1289 DRM_DEBUG_KMS("can clone using command line\n");
1293 /* try and find a 1024x768 mode on each connector */
1295 dmt_mode = drm_mode_find_dmt(fb_helper->dev, 1024, 768, 60, false);
1297 for (i = 0; i < fb_helper->connector_count; i++) {
1302 fb_helper_conn = fb_helper->connector_info[i];
1303 list_for_each_entry(mode, &fb_helper_conn->connector->modes, head) {
1304 if (drm_mode_equal(mode, dmt_mode))
1312 DRM_DEBUG_KMS("can clone using 1024x768\n");
1315 DRM_INFO("kms: can't enable cloning when we probably wanted to.\n");
1319 static bool drm_target_preferred(struct drm_fb_helper *fb_helper,
1320 struct drm_display_mode **modes,
1321 bool *enabled, int width, int height)
1323 struct drm_fb_helper_connector *fb_helper_conn;
1326 for (i = 0; i < fb_helper->connector_count; i++) {
1327 fb_helper_conn = fb_helper->connector_info[i];
1329 if (enabled[i] == false)
1332 DRM_DEBUG_KMS("looking for cmdline mode on connector %d\n",
1333 fb_helper_conn->connector->base.id);
1335 /* got for command line mode first */
1336 modes[i] = drm_pick_cmdline_mode(fb_helper_conn, width, height);
1338 DRM_DEBUG_KMS("looking for preferred mode on connector %d\n",
1339 fb_helper_conn->connector->base.id);
1340 modes[i] = drm_has_preferred_mode(fb_helper_conn, width, height);
1342 /* No preferred modes, pick one off the list */
1343 if (!modes[i] && !list_empty(&fb_helper_conn->connector->modes)) {
1344 list_for_each_entry(modes[i], &fb_helper_conn->connector->modes, head)
1347 DRM_DEBUG_KMS("found mode %s\n", modes[i] ? modes[i]->name :
1353 static int drm_pick_crtcs(struct drm_fb_helper *fb_helper,
1354 struct drm_fb_helper_crtc **best_crtcs,
1355 struct drm_display_mode **modes,
1356 int n, int width, int height)
1359 struct drm_device *dev = fb_helper->dev;
1360 struct drm_connector *connector;
1361 struct drm_connector_helper_funcs *connector_funcs;
1362 struct drm_encoder *encoder;
1363 struct drm_fb_helper_crtc *best_crtc;
1364 int my_score, best_score, score;
1365 struct drm_fb_helper_crtc **crtcs, *crtc;
1366 struct drm_fb_helper_connector *fb_helper_conn;
1368 if (n == fb_helper->connector_count)
1371 fb_helper_conn = fb_helper->connector_info[n];
1372 connector = fb_helper_conn->connector;
1374 best_crtcs[n] = NULL;
1376 best_score = drm_pick_crtcs(fb_helper, best_crtcs, modes, n+1, width, height);
1377 if (modes[n] == NULL)
1380 crtcs = kzalloc(dev->mode_config.num_connector *
1381 sizeof(struct drm_fb_helper_crtc *), GFP_KERNEL);
1386 if (connector->status == connector_status_connected)
1388 if (drm_has_cmdline_mode(fb_helper_conn))
1390 if (drm_has_preferred_mode(fb_helper_conn, width, height))
1393 connector_funcs = connector->helper_private;
1394 encoder = connector_funcs->best_encoder(connector);
1398 /* select a crtc for this connector and then attempt to configure
1399 remaining connectors */
1400 for (c = 0; c < fb_helper->crtc_count; c++) {
1401 crtc = &fb_helper->crtc_info[c];
1403 if ((encoder->possible_crtcs & (1 << c)) == 0)
1406 for (o = 0; o < n; o++)
1407 if (best_crtcs[o] == crtc)
1411 /* ignore cloning unless only a single crtc */
1412 if (fb_helper->crtc_count > 1)
1415 if (!drm_mode_equal(modes[o], modes[n]))
1420 memcpy(crtcs, best_crtcs, n * sizeof(struct drm_fb_helper_crtc *));
1421 score = my_score + drm_pick_crtcs(fb_helper, crtcs, modes, n + 1,
1423 if (score > best_score) {
1426 memcpy(best_crtcs, crtcs,
1427 dev->mode_config.num_connector *
1428 sizeof(struct drm_fb_helper_crtc *));
1436 static void drm_setup_crtcs(struct drm_fb_helper *fb_helper)
1438 struct drm_device *dev = fb_helper->dev;
1439 struct drm_fb_helper_crtc **crtcs;
1440 struct drm_display_mode **modes;
1441 struct drm_mode_set *modeset;
1446 DRM_DEBUG_KMS("\n");
1448 width = dev->mode_config.max_width;
1449 height = dev->mode_config.max_height;
1451 crtcs = kcalloc(dev->mode_config.num_connector,
1452 sizeof(struct drm_fb_helper_crtc *), GFP_KERNEL);
1453 modes = kcalloc(dev->mode_config.num_connector,
1454 sizeof(struct drm_display_mode *), GFP_KERNEL);
1455 enabled = kcalloc(dev->mode_config.num_connector,
1456 sizeof(bool), GFP_KERNEL);
1457 if (!crtcs || !modes || !enabled) {
1458 DRM_ERROR("Memory allocation failed\n");
1463 drm_enable_connectors(fb_helper, enabled);
1465 if (!(fb_helper->funcs->initial_config &&
1466 fb_helper->funcs->initial_config(fb_helper, crtcs, modes,
1467 enabled, width, height))) {
1468 memset(modes, 0, dev->mode_config.num_connector*sizeof(modes[0]));
1469 memset(crtcs, 0, dev->mode_config.num_connector*sizeof(crtcs[0]));
1471 if (!drm_target_cloned(fb_helper,
1472 modes, enabled, width, height) &&
1473 !drm_target_preferred(fb_helper,
1474 modes, enabled, width, height))
1475 DRM_ERROR("Unable to find initial modes\n");
1477 DRM_DEBUG_KMS("picking CRTCs for %dx%d config\n",
1480 drm_pick_crtcs(fb_helper, crtcs, modes, 0, width, height);
1483 /* need to set the modesets up here for use later */
1484 /* fill out the connector<->crtc mappings into the modesets */
1485 for (i = 0; i < fb_helper->crtc_count; i++) {
1486 modeset = &fb_helper->crtc_info[i].mode_set;
1487 modeset->num_connectors = 0;
1491 for (i = 0; i < fb_helper->connector_count; i++) {
1492 struct drm_display_mode *mode = modes[i];
1493 struct drm_fb_helper_crtc *fb_crtc = crtcs[i];
1494 modeset = &fb_crtc->mode_set;
1496 if (mode && fb_crtc) {
1497 DRM_DEBUG_KMS("desired mode %s set on crtc %d\n",
1498 mode->name, fb_crtc->mode_set.crtc->base.id);
1499 fb_crtc->desired_mode = mode;
1501 drm_mode_destroy(dev, modeset->mode);
1502 modeset->mode = drm_mode_duplicate(dev,
1503 fb_crtc->desired_mode);
1504 modeset->connectors[modeset->num_connectors++] = fb_helper->connector_info[i]->connector;
1505 modeset->fb = fb_helper->fb;
1509 /* Clear out any old modes if there are no more connected outputs. */
1510 for (i = 0; i < fb_helper->crtc_count; i++) {
1511 modeset = &fb_helper->crtc_info[i].mode_set;
1512 if (modeset->num_connectors == 0) {
1513 BUG_ON(modeset->fb);
1514 BUG_ON(modeset->num_connectors);
1516 drm_mode_destroy(dev, modeset->mode);
1517 modeset->mode = NULL;
1527 * drm_fb_helper_initial_config - setup a sane initial connector configuration
1528 * @fb_helper: fb_helper device struct
1529 * @bpp_sel: bpp value to use for the framebuffer configuration
1531 * Scans the CRTCs and connectors and tries to put together an initial setup.
1532 * At the moment, this is a cloned configuration across all heads with
1533 * a new framebuffer object as the backing store.
1535 * Note that this also registers the fbdev and so allows userspace to call into
1536 * the driver through the fbdev interfaces.
1538 * This function will call down into the ->fb_probe callback to let
1539 * the driver allocate and initialize the fbdev info structure and the drm
1540 * framebuffer used to back the fbdev. drm_fb_helper_fill_var() and
1541 * drm_fb_helper_fill_fix() are provided as helpers to setup simple default
1542 * values for the fbdev info structure.
1545 * Zero if everything went ok, nonzero otherwise.
1547 bool drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper, int bpp_sel)
1549 struct drm_device *dev = fb_helper->dev;
1552 drm_fb_helper_parse_command_line(fb_helper);
1554 count = drm_fb_helper_probe_connector_modes(fb_helper,
1555 dev->mode_config.max_width,
1556 dev->mode_config.max_height);
1558 * we shouldn't end up with no modes here.
1561 dev_info(fb_helper->dev->dev, "No connectors reported connected with modes\n");
1563 drm_setup_crtcs(fb_helper);
1565 return drm_fb_helper_single_fb_probe(fb_helper, bpp_sel);
1567 EXPORT_SYMBOL(drm_fb_helper_initial_config);
1570 * drm_fb_helper_hotplug_event - respond to a hotplug notification by
1571 * probing all the outputs attached to the fb
1572 * @fb_helper: the drm_fb_helper
1574 * Scan the connectors attached to the fb_helper and try to put together a
1575 * setup after *notification of a change in output configuration.
1577 * Called at runtime, takes the mode config locks to be able to check/change the
1578 * modeset configuration. Must be run from process context (which usually means
1579 * either the output polling work or a work item launched from the driver's
1580 * hotplug interrupt).
1582 * Note that the driver must ensure that this is only called _after_ the fb has
1583 * been fully set up, i.e. after the call to drm_fb_helper_initial_config.
1586 * 0 on success and a non-zero error code otherwise.
1588 int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
1590 struct drm_device *dev = fb_helper->dev;
1592 u32 max_width, max_height, bpp_sel;
1597 mutex_lock(&fb_helper->dev->mode_config.mutex);
1598 if (!drm_fb_helper_is_bound(fb_helper)) {
1599 fb_helper->delayed_hotplug = true;
1600 mutex_unlock(&fb_helper->dev->mode_config.mutex);
1603 DRM_DEBUG_KMS("\n");
1605 max_width = fb_helper->fb->width;
1606 max_height = fb_helper->fb->height;
1607 bpp_sel = fb_helper->fb->bits_per_pixel;
1609 count = drm_fb_helper_probe_connector_modes(fb_helper, max_width,
1611 mutex_unlock(&fb_helper->dev->mode_config.mutex);
1613 drm_modeset_lock_all(dev);
1614 drm_setup_crtcs(fb_helper);
1615 drm_modeset_unlock_all(dev);
1616 drm_fb_helper_set_par(fb_helper->fbdev);
1620 EXPORT_SYMBOL(drm_fb_helper_hotplug_event);
1622 /* The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
1623 * but the module doesn't depend on any fb console symbols. At least
1624 * attempt to load fbcon to avoid leaving the system without a usable console.
1626 #if defined(CONFIG_FRAMEBUFFER_CONSOLE_MODULE) && !defined(CONFIG_EXPERT)
1627 static int __init drm_fb_helper_modinit(void)
1629 const char *name = "fbcon";
1630 struct module *fbcon;
1632 mutex_lock(&module_mutex);
1633 fbcon = find_module(name);
1634 mutex_unlock(&module_mutex);
1637 request_module_nowait(name);
1641 module_init(drm_fb_helper_modinit);