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 * For each CRTC in this fb, turn the connectors on/off.
421 drm_modeset_lock_all(dev);
422 if (!drm_fb_helper_is_bound(fb_helper)) {
423 drm_modeset_unlock_all(dev);
427 for (i = 0; i < fb_helper->crtc_count; i++) {
428 crtc = fb_helper->crtc_info[i].mode_set.crtc;
433 /* Walk the connectors & encoders on this fb turning them on/off */
434 for (j = 0; j < fb_helper->connector_count; j++) {
435 connector = fb_helper->connector_info[j]->connector;
436 connector->funcs->dpms(connector, dpms_mode);
437 drm_object_property_set_value(&connector->base,
438 dev->mode_config.dpms_property, dpms_mode);
441 drm_modeset_unlock_all(dev);
445 * drm_fb_helper_blank - implementation for ->fb_blank
446 * @blank: desired blanking state
447 * @info: fbdev registered by the helper
449 int drm_fb_helper_blank(int blank, struct fb_info *info)
452 /* Display: On; HSync: On, VSync: On */
453 case FB_BLANK_UNBLANK:
454 drm_fb_helper_dpms(info, DRM_MODE_DPMS_ON);
456 /* Display: Off; HSync: On, VSync: On */
457 case FB_BLANK_NORMAL:
458 drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
460 /* Display: Off; HSync: Off, VSync: On */
461 case FB_BLANK_HSYNC_SUSPEND:
462 drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
464 /* Display: Off; HSync: On, VSync: Off */
465 case FB_BLANK_VSYNC_SUSPEND:
466 drm_fb_helper_dpms(info, DRM_MODE_DPMS_SUSPEND);
468 /* Display: Off; HSync: Off, VSync: Off */
469 case FB_BLANK_POWERDOWN:
470 drm_fb_helper_dpms(info, DRM_MODE_DPMS_OFF);
475 EXPORT_SYMBOL(drm_fb_helper_blank);
477 static void drm_fb_helper_crtc_free(struct drm_fb_helper *helper)
481 for (i = 0; i < helper->connector_count; i++)
482 kfree(helper->connector_info[i]);
483 kfree(helper->connector_info);
484 for (i = 0; i < helper->crtc_count; i++) {
485 kfree(helper->crtc_info[i].mode_set.connectors);
486 if (helper->crtc_info[i].mode_set.mode)
487 drm_mode_destroy(helper->dev, helper->crtc_info[i].mode_set.mode);
489 kfree(helper->crtc_info);
493 * drm_fb_helper_init - initialize a drm_fb_helper structure
495 * @fb_helper: driver-allocated fbdev helper structure to initialize
496 * @crtc_count: maximum number of crtcs to support in this fbdev emulation
497 * @max_conn_count: max connector count
499 * This allocates the structures for the fbdev helper with the given limits.
500 * Note that this won't yet touch the hardware (through the driver interfaces)
501 * nor register the fbdev. This is only done in drm_fb_helper_initial_config()
502 * to allow driver writes more control over the exact init sequence.
504 * Drivers must set fb_helper->funcs before calling
505 * drm_fb_helper_initial_config().
508 * Zero if everything went ok, nonzero otherwise.
510 int drm_fb_helper_init(struct drm_device *dev,
511 struct drm_fb_helper *fb_helper,
512 int crtc_count, int max_conn_count)
514 struct drm_crtc *crtc;
517 fb_helper->dev = dev;
519 INIT_LIST_HEAD(&fb_helper->kernel_fb_list);
521 fb_helper->crtc_info = kcalloc(crtc_count, sizeof(struct drm_fb_helper_crtc), GFP_KERNEL);
522 if (!fb_helper->crtc_info)
525 fb_helper->crtc_count = crtc_count;
526 fb_helper->connector_info = kcalloc(dev->mode_config.num_connector, sizeof(struct drm_fb_helper_connector *), GFP_KERNEL);
527 if (!fb_helper->connector_info) {
528 kfree(fb_helper->crtc_info);
531 fb_helper->connector_count = 0;
533 for (i = 0; i < crtc_count; i++) {
534 fb_helper->crtc_info[i].mode_set.connectors =
535 kcalloc(max_conn_count,
536 sizeof(struct drm_connector *),
539 if (!fb_helper->crtc_info[i].mode_set.connectors)
541 fb_helper->crtc_info[i].mode_set.num_connectors = 0;
545 list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
546 fb_helper->crtc_info[i].mode_set.crtc = crtc;
552 drm_fb_helper_crtc_free(fb_helper);
555 EXPORT_SYMBOL(drm_fb_helper_init);
557 void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
559 if (!list_empty(&fb_helper->kernel_fb_list)) {
560 list_del(&fb_helper->kernel_fb_list);
561 if (list_empty(&kernel_fb_helper_list)) {
562 pr_info("drm: unregistered panic notifier\n");
563 atomic_notifier_chain_unregister(&panic_notifier_list,
565 unregister_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
569 drm_fb_helper_crtc_free(fb_helper);
572 EXPORT_SYMBOL(drm_fb_helper_fini);
574 static int setcolreg(struct drm_crtc *crtc, u16 red, u16 green,
575 u16 blue, u16 regno, struct fb_info *info)
577 struct drm_fb_helper *fb_helper = info->par;
578 struct drm_framebuffer *fb = fb_helper->fb;
581 if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
584 /* place color in psuedopalette */
587 palette = (u32 *)info->pseudo_palette;
588 red >>= (16 - info->var.red.length);
589 green >>= (16 - info->var.green.length);
590 blue >>= (16 - info->var.blue.length);
591 value = (red << info->var.red.offset) |
592 (green << info->var.green.offset) |
593 (blue << info->var.blue.offset);
594 if (info->var.transp.length > 0) {
595 u32 mask = (1 << info->var.transp.length) - 1;
596 mask <<= info->var.transp.offset;
599 palette[regno] = value;
604 * The driver really shouldn't advertise pseudo/directcolor
605 * visuals if it can't deal with the palette.
607 if (WARN_ON(!fb_helper->funcs->gamma_set ||
608 !fb_helper->funcs->gamma_get))
613 if (fb->bits_per_pixel == 16) {
616 if (fb->depth == 16 && regno > 63)
618 if (fb->depth == 15 && regno > 31)
621 if (fb->depth == 16) {
625 for (i = 0; i < 8; i++)
626 fb_helper->funcs->gamma_set(crtc, red,
627 green, blue, pindex + i);
630 fb_helper->funcs->gamma_get(crtc, &r,
634 for (i = 0; i < 4; i++)
635 fb_helper->funcs->gamma_set(crtc, r,
642 fb_helper->funcs->gamma_set(crtc, red, green, blue, pindex);
647 * drm_fb_helper_setcmap - implementation for ->fb_setcmap
649 * @info: fbdev registered by the helper
651 int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
653 struct drm_fb_helper *fb_helper = info->par;
654 struct drm_device *dev = fb_helper->dev;
655 struct drm_crtc_helper_funcs *crtc_funcs;
656 u16 *red, *green, *blue, *transp;
657 struct drm_crtc *crtc;
661 drm_modeset_lock_all(dev);
662 if (!drm_fb_helper_is_bound(fb_helper)) {
663 drm_modeset_unlock_all(dev);
667 for (i = 0; i < fb_helper->crtc_count; i++) {
668 crtc = fb_helper->crtc_info[i].mode_set.crtc;
669 crtc_funcs = crtc->helper_private;
674 transp = cmap->transp;
677 for (j = 0; j < cmap->len; j++) {
678 u16 hred, hgreen, hblue, htransp = 0xffff;
687 rc = setcolreg(crtc, hred, hgreen, hblue, start++, info);
691 if (crtc_funcs->load_lut)
692 crtc_funcs->load_lut(crtc);
695 drm_modeset_unlock_all(dev);
698 EXPORT_SYMBOL(drm_fb_helper_setcmap);
701 * drm_fb_helper_check_var - implementation for ->fb_check_var
702 * @var: screeninfo to check
703 * @info: fbdev registered by the helper
705 int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
706 struct fb_info *info)
708 struct drm_fb_helper *fb_helper = info->par;
709 struct drm_framebuffer *fb = fb_helper->fb;
712 if (var->pixclock != 0 || in_dbg_master())
715 /* Need to resize the fb object !!! */
716 if (var->bits_per_pixel > fb->bits_per_pixel ||
717 var->xres > fb->width || var->yres > fb->height ||
718 var->xres_virtual > fb->width || var->yres_virtual > fb->height) {
719 DRM_DEBUG("fb userspace requested width/height/bpp is greater than current fb "
720 "request %dx%d-%d (virtual %dx%d) > %dx%d-%d\n",
721 var->xres, var->yres, var->bits_per_pixel,
722 var->xres_virtual, var->yres_virtual,
723 fb->width, fb->height, fb->bits_per_pixel);
727 switch (var->bits_per_pixel) {
729 depth = (var->green.length == 6) ? 16 : 15;
732 depth = (var->transp.length > 0) ? 32 : 24;
735 depth = var->bits_per_pixel;
742 var->green.offset = 0;
743 var->blue.offset = 0;
745 var->green.length = 8;
746 var->blue.length = 8;
747 var->transp.length = 0;
748 var->transp.offset = 0;
751 var->red.offset = 10;
752 var->green.offset = 5;
753 var->blue.offset = 0;
755 var->green.length = 5;
756 var->blue.length = 5;
757 var->transp.length = 1;
758 var->transp.offset = 15;
761 var->red.offset = 11;
762 var->green.offset = 5;
763 var->blue.offset = 0;
765 var->green.length = 6;
766 var->blue.length = 5;
767 var->transp.length = 0;
768 var->transp.offset = 0;
771 var->red.offset = 16;
772 var->green.offset = 8;
773 var->blue.offset = 0;
775 var->green.length = 8;
776 var->blue.length = 8;
777 var->transp.length = 0;
778 var->transp.offset = 0;
781 var->red.offset = 16;
782 var->green.offset = 8;
783 var->blue.offset = 0;
785 var->green.length = 8;
786 var->blue.length = 8;
787 var->transp.length = 8;
788 var->transp.offset = 24;
795 EXPORT_SYMBOL(drm_fb_helper_check_var);
798 * drm_fb_helper_set_par - implementation for ->fb_set_par
799 * @info: fbdev registered by the helper
801 * This will let fbcon do the mode init and is called at initialization time by
802 * the fbdev core when registering the driver, and later on through the hotplug
805 int drm_fb_helper_set_par(struct fb_info *info)
807 struct drm_fb_helper *fb_helper = info->par;
808 struct drm_device *dev = fb_helper->dev;
809 struct fb_var_screeninfo *var = &info->var;
813 if (var->pixclock != 0) {
814 DRM_ERROR("PIXEL CLOCK SET\n");
818 drm_modeset_lock_all(dev);
819 for (i = 0; i < fb_helper->crtc_count; i++) {
820 ret = drm_mode_set_config_internal(&fb_helper->crtc_info[i].mode_set);
822 drm_modeset_unlock_all(dev);
826 drm_modeset_unlock_all(dev);
828 if (fb_helper->delayed_hotplug) {
829 fb_helper->delayed_hotplug = false;
830 drm_fb_helper_hotplug_event(fb_helper);
834 EXPORT_SYMBOL(drm_fb_helper_set_par);
837 * drm_fb_helper_pan_display - implementation for ->fb_pan_display
838 * @var: updated screen information
839 * @info: fbdev registered by the helper
841 int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
842 struct fb_info *info)
844 struct drm_fb_helper *fb_helper = info->par;
845 struct drm_device *dev = fb_helper->dev;
846 struct drm_mode_set *modeset;
847 struct drm_crtc *crtc;
851 drm_modeset_lock_all(dev);
852 if (!drm_fb_helper_is_bound(fb_helper)) {
853 drm_modeset_unlock_all(dev);
857 for (i = 0; i < fb_helper->crtc_count; i++) {
858 crtc = fb_helper->crtc_info[i].mode_set.crtc;
860 modeset = &fb_helper->crtc_info[i].mode_set;
862 modeset->x = var->xoffset;
863 modeset->y = var->yoffset;
865 if (modeset->num_connectors) {
866 ret = drm_mode_set_config_internal(modeset);
868 info->var.xoffset = var->xoffset;
869 info->var.yoffset = var->yoffset;
873 drm_modeset_unlock_all(dev);
876 EXPORT_SYMBOL(drm_fb_helper_pan_display);
879 * Allocates the backing storage and sets up the fbdev info structure through
880 * the ->fb_probe callback and then registers the fbdev and sets up the panic
883 static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
889 struct fb_info *info;
890 struct drm_fb_helper_surface_size sizes;
893 memset(&sizes, 0, sizeof(struct drm_fb_helper_surface_size));
894 sizes.surface_depth = 24;
895 sizes.surface_bpp = 32;
896 sizes.fb_width = (unsigned)-1;
897 sizes.fb_height = (unsigned)-1;
899 /* if driver picks 8 or 16 by default use that
900 for both depth/bpp */
901 if (preferred_bpp != sizes.surface_bpp)
902 sizes.surface_depth = sizes.surface_bpp = preferred_bpp;
904 /* first up get a count of crtcs now in use and new min/maxes width/heights */
905 for (i = 0; i < fb_helper->connector_count; i++) {
906 struct drm_fb_helper_connector *fb_helper_conn = fb_helper->connector_info[i];
907 struct drm_cmdline_mode *cmdline_mode;
909 cmdline_mode = &fb_helper_conn->cmdline_mode;
911 if (cmdline_mode->bpp_specified) {
912 switch (cmdline_mode->bpp) {
914 sizes.surface_depth = sizes.surface_bpp = 8;
917 sizes.surface_depth = 15;
918 sizes.surface_bpp = 16;
921 sizes.surface_depth = sizes.surface_bpp = 16;
924 sizes.surface_depth = sizes.surface_bpp = 24;
927 sizes.surface_depth = 24;
928 sizes.surface_bpp = 32;
936 for (i = 0; i < fb_helper->crtc_count; i++) {
937 struct drm_display_mode *desired_mode;
938 desired_mode = fb_helper->crtc_info[i].desired_mode;
942 gamma_size = fb_helper->crtc_info[i].mode_set.crtc->gamma_size;
943 if (desired_mode->hdisplay < sizes.fb_width)
944 sizes.fb_width = desired_mode->hdisplay;
945 if (desired_mode->vdisplay < sizes.fb_height)
946 sizes.fb_height = desired_mode->vdisplay;
947 if (desired_mode->hdisplay > sizes.surface_width)
948 sizes.surface_width = desired_mode->hdisplay;
949 if (desired_mode->vdisplay > sizes.surface_height)
950 sizes.surface_height = desired_mode->vdisplay;
955 if (crtc_count == 0 || sizes.fb_width == -1 || sizes.fb_height == -1) {
956 /* hmm everyone went away - assume VGA cable just fell out
957 and will come back later. */
958 DRM_INFO("Cannot find any crtc or sizes - going 1024x768\n");
959 sizes.fb_width = sizes.surface_width = 1024;
960 sizes.fb_height = sizes.surface_height = 768;
963 /* push down into drivers */
964 ret = (*fb_helper->funcs->fb_probe)(fb_helper, &sizes);
968 info = fb_helper->fbdev;
971 * Set the fb pointer - usually drm_setup_crtcs does this for hotplug
972 * events, but at init time drm_setup_crtcs needs to be called before
973 * the fb is allocated (since we need to figure out the desired size of
974 * the fb before we can allocate it ...). Hence we need to fix things up
977 for (i = 0; i < fb_helper->crtc_count; i++)
978 if (fb_helper->crtc_info[i].mode_set.num_connectors)
979 fb_helper->crtc_info[i].mode_set.fb = fb_helper->fb;
982 info->var.pixclock = 0;
983 if (register_framebuffer(info) < 0)
986 dev_info(fb_helper->dev->dev, "fb%d: %s frame buffer device\n",
987 info->node, info->fix.id);
989 /* Switch back to kernel console on panic */
990 /* multi card linked list maybe */
991 if (list_empty(&kernel_fb_helper_list)) {
992 dev_info(fb_helper->dev->dev, "registered panic notifier\n");
993 atomic_notifier_chain_register(&panic_notifier_list,
995 register_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
998 list_add(&fb_helper->kernel_fb_list, &kernel_fb_helper_list);
1004 * drm_fb_helper_fill_fix - initializes fixed fbdev information
1005 * @info: fbdev registered by the helper
1006 * @pitch: desired pitch
1007 * @depth: desired depth
1009 * Helper to fill in the fixed fbdev information useful for a non-accelerated
1010 * fbdev emulations. Drivers which support acceleration methods which impose
1011 * additional constraints need to set up their own limits.
1013 * Drivers should call this (or their equivalent setup code) from their
1014 * ->fb_probe callback.
1016 void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
1019 info->fix.type = FB_TYPE_PACKED_PIXELS;
1020 info->fix.visual = depth == 8 ? FB_VISUAL_PSEUDOCOLOR :
1021 FB_VISUAL_TRUECOLOR;
1022 info->fix.mmio_start = 0;
1023 info->fix.mmio_len = 0;
1024 info->fix.type_aux = 0;
1025 info->fix.xpanstep = 1; /* doing it in hw */
1026 info->fix.ypanstep = 1; /* doing it in hw */
1027 info->fix.ywrapstep = 0;
1028 info->fix.accel = FB_ACCEL_NONE;
1029 info->fix.type_aux = 0;
1031 info->fix.line_length = pitch;
1034 EXPORT_SYMBOL(drm_fb_helper_fill_fix);
1037 * drm_fb_helper_fill_var - initalizes variable fbdev information
1038 * @info: fbdev instance to set up
1039 * @fb_helper: fb helper instance to use as template
1040 * @fb_width: desired fb width
1041 * @fb_height: desired fb height
1043 * Sets up the variable fbdev metainformation from the given fb helper instance
1044 * and the drm framebuffer allocated in fb_helper->fb.
1046 * Drivers should call this (or their equivalent setup code) from their
1047 * ->fb_probe callback after having allocated the fbdev backing
1048 * storage framebuffer.
1050 void drm_fb_helper_fill_var(struct fb_info *info, struct drm_fb_helper *fb_helper,
1051 uint32_t fb_width, uint32_t fb_height)
1053 struct drm_framebuffer *fb = fb_helper->fb;
1054 info->pseudo_palette = fb_helper->pseudo_palette;
1055 info->var.xres_virtual = fb->width;
1056 info->var.yres_virtual = fb->height;
1057 info->var.bits_per_pixel = fb->bits_per_pixel;
1058 info->var.accel_flags = FB_ACCELF_TEXT;
1059 info->var.xoffset = 0;
1060 info->var.yoffset = 0;
1061 info->var.activate = FB_ACTIVATE_NOW;
1062 info->var.height = -1;
1063 info->var.width = -1;
1065 switch (fb->depth) {
1067 info->var.red.offset = 0;
1068 info->var.green.offset = 0;
1069 info->var.blue.offset = 0;
1070 info->var.red.length = 8; /* 8bit DAC */
1071 info->var.green.length = 8;
1072 info->var.blue.length = 8;
1073 info->var.transp.offset = 0;
1074 info->var.transp.length = 0;
1077 info->var.red.offset = 10;
1078 info->var.green.offset = 5;
1079 info->var.blue.offset = 0;
1080 info->var.red.length = 5;
1081 info->var.green.length = 5;
1082 info->var.blue.length = 5;
1083 info->var.transp.offset = 15;
1084 info->var.transp.length = 1;
1087 info->var.red.offset = 11;
1088 info->var.green.offset = 5;
1089 info->var.blue.offset = 0;
1090 info->var.red.length = 5;
1091 info->var.green.length = 6;
1092 info->var.blue.length = 5;
1093 info->var.transp.offset = 0;
1096 info->var.red.offset = 16;
1097 info->var.green.offset = 8;
1098 info->var.blue.offset = 0;
1099 info->var.red.length = 8;
1100 info->var.green.length = 8;
1101 info->var.blue.length = 8;
1102 info->var.transp.offset = 0;
1103 info->var.transp.length = 0;
1106 info->var.red.offset = 16;
1107 info->var.green.offset = 8;
1108 info->var.blue.offset = 0;
1109 info->var.red.length = 8;
1110 info->var.green.length = 8;
1111 info->var.blue.length = 8;
1112 info->var.transp.offset = 24;
1113 info->var.transp.length = 8;
1119 info->var.xres = fb_width;
1120 info->var.yres = fb_height;
1122 EXPORT_SYMBOL(drm_fb_helper_fill_var);
1124 static int drm_fb_helper_probe_connector_modes(struct drm_fb_helper *fb_helper,
1128 struct drm_connector *connector;
1132 for (i = 0; i < fb_helper->connector_count; i++) {
1133 connector = fb_helper->connector_info[i]->connector;
1134 count += connector->funcs->fill_modes(connector, maxX, maxY);
1140 static struct drm_display_mode *drm_has_preferred_mode(struct drm_fb_helper_connector *fb_connector, int width, int height)
1142 struct drm_display_mode *mode;
1144 list_for_each_entry(mode, &fb_connector->connector->modes, head) {
1145 if (drm_mode_width(mode) > width ||
1146 drm_mode_height(mode) > height)
1148 if (mode->type & DRM_MODE_TYPE_PREFERRED)
1154 static bool drm_has_cmdline_mode(struct drm_fb_helper_connector *fb_connector)
1156 struct drm_cmdline_mode *cmdline_mode;
1157 cmdline_mode = &fb_connector->cmdline_mode;
1158 return cmdline_mode->specified;
1161 static struct drm_display_mode *drm_pick_cmdline_mode(struct drm_fb_helper_connector *fb_helper_conn,
1162 int width, int height)
1164 struct drm_cmdline_mode *cmdline_mode;
1165 struct drm_display_mode *mode = NULL;
1167 cmdline_mode = &fb_helper_conn->cmdline_mode;
1168 if (cmdline_mode->specified == false)
1171 /* attempt to find a matching mode in the list of modes
1172 * we have gotten so far, if not add a CVT mode that conforms
1174 if (cmdline_mode->rb || cmdline_mode->margins)
1177 list_for_each_entry(mode, &fb_helper_conn->connector->modes, head) {
1178 /* check width/height */
1179 if (mode->hdisplay != cmdline_mode->xres ||
1180 mode->vdisplay != cmdline_mode->yres)
1183 if (cmdline_mode->refresh_specified) {
1184 if (mode->vrefresh != cmdline_mode->refresh)
1188 if (cmdline_mode->interlace) {
1189 if (!(mode->flags & DRM_MODE_FLAG_INTERLACE))
1196 mode = drm_mode_create_from_cmdline_mode(fb_helper_conn->connector->dev,
1198 list_add(&mode->head, &fb_helper_conn->connector->modes);
1202 static bool drm_connector_enabled(struct drm_connector *connector, bool strict)
1207 enable = connector->status == connector_status_connected;
1209 enable = connector->status != connector_status_disconnected;
1214 static void drm_enable_connectors(struct drm_fb_helper *fb_helper,
1217 bool any_enabled = false;
1218 struct drm_connector *connector;
1221 for (i = 0; i < fb_helper->connector_count; i++) {
1222 connector = fb_helper->connector_info[i]->connector;
1223 enabled[i] = drm_connector_enabled(connector, true);
1224 DRM_DEBUG_KMS("connector %d enabled? %s\n", connector->base.id,
1225 enabled[i] ? "yes" : "no");
1226 any_enabled |= enabled[i];
1232 for (i = 0; i < fb_helper->connector_count; i++) {
1233 connector = fb_helper->connector_info[i]->connector;
1234 enabled[i] = drm_connector_enabled(connector, false);
1238 static bool drm_target_cloned(struct drm_fb_helper *fb_helper,
1239 struct drm_display_mode **modes,
1240 bool *enabled, int width, int height)
1243 bool can_clone = false;
1244 struct drm_fb_helper_connector *fb_helper_conn;
1245 struct drm_display_mode *dmt_mode, *mode;
1247 /* only contemplate cloning in the single crtc case */
1248 if (fb_helper->crtc_count > 1)
1252 for (i = 0; i < fb_helper->connector_count; i++) {
1257 /* only contemplate cloning if more than one connector is enabled */
1261 /* check the command line or if nothing common pick 1024x768 */
1263 for (i = 0; i < fb_helper->connector_count; i++) {
1266 fb_helper_conn = fb_helper->connector_info[i];
1267 modes[i] = drm_pick_cmdline_mode(fb_helper_conn, width, height);
1272 for (j = 0; j < i; j++) {
1275 if (!drm_mode_equal(modes[j], modes[i]))
1281 DRM_DEBUG_KMS("can clone using command line\n");
1285 /* try and find a 1024x768 mode on each connector */
1287 dmt_mode = drm_mode_find_dmt(fb_helper->dev, 1024, 768, 60, false);
1289 for (i = 0; i < fb_helper->connector_count; i++) {
1294 fb_helper_conn = fb_helper->connector_info[i];
1295 list_for_each_entry(mode, &fb_helper_conn->connector->modes, head) {
1296 if (drm_mode_equal(mode, dmt_mode))
1304 DRM_DEBUG_KMS("can clone using 1024x768\n");
1307 DRM_INFO("kms: can't enable cloning when we probably wanted to.\n");
1311 static bool drm_target_preferred(struct drm_fb_helper *fb_helper,
1312 struct drm_display_mode **modes,
1313 bool *enabled, int width, int height)
1315 struct drm_fb_helper_connector *fb_helper_conn;
1318 for (i = 0; i < fb_helper->connector_count; i++) {
1319 fb_helper_conn = fb_helper->connector_info[i];
1321 if (enabled[i] == false)
1324 DRM_DEBUG_KMS("looking for cmdline mode on connector %d\n",
1325 fb_helper_conn->connector->base.id);
1327 /* got for command line mode first */
1328 modes[i] = drm_pick_cmdline_mode(fb_helper_conn, width, height);
1330 DRM_DEBUG_KMS("looking for preferred mode on connector %d\n",
1331 fb_helper_conn->connector->base.id);
1332 modes[i] = drm_has_preferred_mode(fb_helper_conn, width, height);
1334 /* No preferred modes, pick one off the list */
1335 if (!modes[i] && !list_empty(&fb_helper_conn->connector->modes)) {
1336 list_for_each_entry(modes[i], &fb_helper_conn->connector->modes, head)
1339 DRM_DEBUG_KMS("found mode %s\n", modes[i] ? modes[i]->name :
1345 static int drm_pick_crtcs(struct drm_fb_helper *fb_helper,
1346 struct drm_fb_helper_crtc **best_crtcs,
1347 struct drm_display_mode **modes,
1348 int n, int width, int height)
1351 struct drm_device *dev = fb_helper->dev;
1352 struct drm_connector *connector;
1353 struct drm_connector_helper_funcs *connector_funcs;
1354 struct drm_encoder *encoder;
1355 struct drm_fb_helper_crtc *best_crtc;
1356 int my_score, best_score, score;
1357 struct drm_fb_helper_crtc **crtcs, *crtc;
1358 struct drm_fb_helper_connector *fb_helper_conn;
1360 if (n == fb_helper->connector_count)
1363 fb_helper_conn = fb_helper->connector_info[n];
1364 connector = fb_helper_conn->connector;
1366 best_crtcs[n] = NULL;
1368 best_score = drm_pick_crtcs(fb_helper, best_crtcs, modes, n+1, width, height);
1369 if (modes[n] == NULL)
1372 crtcs = kzalloc(dev->mode_config.num_connector *
1373 sizeof(struct drm_fb_helper_crtc *), GFP_KERNEL);
1378 if (connector->status == connector_status_connected)
1380 if (drm_has_cmdline_mode(fb_helper_conn))
1382 if (drm_has_preferred_mode(fb_helper_conn, width, height))
1385 connector_funcs = connector->helper_private;
1386 encoder = connector_funcs->best_encoder(connector);
1390 /* select a crtc for this connector and then attempt to configure
1391 remaining connectors */
1392 for (c = 0; c < fb_helper->crtc_count; c++) {
1393 crtc = &fb_helper->crtc_info[c];
1395 if ((encoder->possible_crtcs & (1 << c)) == 0)
1398 for (o = 0; o < n; o++)
1399 if (best_crtcs[o] == crtc)
1403 /* ignore cloning unless only a single crtc */
1404 if (fb_helper->crtc_count > 1)
1407 if (!drm_mode_equal(modes[o], modes[n]))
1412 memcpy(crtcs, best_crtcs, n * sizeof(struct drm_fb_helper_crtc *));
1413 score = my_score + drm_pick_crtcs(fb_helper, crtcs, modes, n + 1,
1415 if (score > best_score) {
1418 memcpy(best_crtcs, crtcs,
1419 dev->mode_config.num_connector *
1420 sizeof(struct drm_fb_helper_crtc *));
1428 static void drm_setup_crtcs(struct drm_fb_helper *fb_helper)
1430 struct drm_device *dev = fb_helper->dev;
1431 struct drm_fb_helper_crtc **crtcs;
1432 struct drm_display_mode **modes;
1433 struct drm_mode_set *modeset;
1438 DRM_DEBUG_KMS("\n");
1440 width = dev->mode_config.max_width;
1441 height = dev->mode_config.max_height;
1443 crtcs = kcalloc(dev->mode_config.num_connector,
1444 sizeof(struct drm_fb_helper_crtc *), GFP_KERNEL);
1445 modes = kcalloc(dev->mode_config.num_connector,
1446 sizeof(struct drm_display_mode *), GFP_KERNEL);
1447 enabled = kcalloc(dev->mode_config.num_connector,
1448 sizeof(bool), GFP_KERNEL);
1449 if (!crtcs || !modes || !enabled) {
1450 DRM_ERROR("Memory allocation failed\n");
1455 drm_enable_connectors(fb_helper, enabled);
1457 if (!(fb_helper->funcs->initial_config &&
1458 fb_helper->funcs->initial_config(fb_helper, crtcs, modes,
1459 enabled, width, height))) {
1460 memset(modes, 0, dev->mode_config.num_connector*sizeof(modes[0]));
1461 memset(crtcs, 0, dev->mode_config.num_connector*sizeof(crtcs[0]));
1463 if (!drm_target_cloned(fb_helper,
1464 modes, enabled, width, height) &&
1465 !drm_target_preferred(fb_helper,
1466 modes, enabled, width, height))
1467 DRM_ERROR("Unable to find initial modes\n");
1469 DRM_DEBUG_KMS("picking CRTCs for %dx%d config\n",
1472 drm_pick_crtcs(fb_helper, crtcs, modes, 0, width, height);
1475 /* need to set the modesets up here for use later */
1476 /* fill out the connector<->crtc mappings into the modesets */
1477 for (i = 0; i < fb_helper->crtc_count; i++) {
1478 modeset = &fb_helper->crtc_info[i].mode_set;
1479 modeset->num_connectors = 0;
1483 for (i = 0; i < fb_helper->connector_count; i++) {
1484 struct drm_display_mode *mode = modes[i];
1485 struct drm_fb_helper_crtc *fb_crtc = crtcs[i];
1486 modeset = &fb_crtc->mode_set;
1488 if (mode && fb_crtc) {
1489 DRM_DEBUG_KMS("desired mode %s set on crtc %d\n",
1490 mode->name, fb_crtc->mode_set.crtc->base.id);
1491 fb_crtc->desired_mode = mode;
1493 drm_mode_destroy(dev, modeset->mode);
1494 modeset->mode = drm_mode_duplicate(dev,
1495 fb_crtc->desired_mode);
1496 modeset->connectors[modeset->num_connectors++] = fb_helper->connector_info[i]->connector;
1497 modeset->fb = fb_helper->fb;
1501 /* Clear out any old modes if there are no more connected outputs. */
1502 for (i = 0; i < fb_helper->crtc_count; i++) {
1503 modeset = &fb_helper->crtc_info[i].mode_set;
1504 if (modeset->num_connectors == 0) {
1505 BUG_ON(modeset->fb);
1506 BUG_ON(modeset->num_connectors);
1508 drm_mode_destroy(dev, modeset->mode);
1509 modeset->mode = NULL;
1519 * drm_fb_helper_initial_config - setup a sane initial connector configuration
1520 * @fb_helper: fb_helper device struct
1521 * @bpp_sel: bpp value to use for the framebuffer configuration
1523 * Scans the CRTCs and connectors and tries to put together an initial setup.
1524 * At the moment, this is a cloned configuration across all heads with
1525 * a new framebuffer object as the backing store.
1527 * Note that this also registers the fbdev and so allows userspace to call into
1528 * the driver through the fbdev interfaces.
1530 * This function will call down into the ->fb_probe callback to let
1531 * the driver allocate and initialize the fbdev info structure and the drm
1532 * framebuffer used to back the fbdev. drm_fb_helper_fill_var() and
1533 * drm_fb_helper_fill_fix() are provided as helpers to setup simple default
1534 * values for the fbdev info structure.
1537 * Zero if everything went ok, nonzero otherwise.
1539 bool drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper, int bpp_sel)
1541 struct drm_device *dev = fb_helper->dev;
1544 drm_fb_helper_parse_command_line(fb_helper);
1546 count = drm_fb_helper_probe_connector_modes(fb_helper,
1547 dev->mode_config.max_width,
1548 dev->mode_config.max_height);
1550 * we shouldn't end up with no modes here.
1553 dev_info(fb_helper->dev->dev, "No connectors reported connected with modes\n");
1555 drm_setup_crtcs(fb_helper);
1557 return drm_fb_helper_single_fb_probe(fb_helper, bpp_sel);
1559 EXPORT_SYMBOL(drm_fb_helper_initial_config);
1562 * drm_fb_helper_hotplug_event - respond to a hotplug notification by
1563 * probing all the outputs attached to the fb
1564 * @fb_helper: the drm_fb_helper
1566 * Scan the connectors attached to the fb_helper and try to put together a
1567 * setup after *notification of a change in output configuration.
1569 * Called at runtime, takes the mode config locks to be able to check/change the
1570 * modeset configuration. Must be run from process context (which usually means
1571 * either the output polling work or a work item launched from the driver's
1572 * hotplug interrupt).
1574 * Note that the driver must ensure that this is only called _after_ the fb has
1575 * been fully set up, i.e. after the call to drm_fb_helper_initial_config.
1578 * 0 on success and a non-zero error code otherwise.
1580 int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
1582 struct drm_device *dev = fb_helper->dev;
1584 u32 max_width, max_height, bpp_sel;
1589 mutex_lock(&fb_helper->dev->mode_config.mutex);
1590 if (!drm_fb_helper_is_bound(fb_helper)) {
1591 fb_helper->delayed_hotplug = true;
1592 mutex_unlock(&fb_helper->dev->mode_config.mutex);
1595 DRM_DEBUG_KMS("\n");
1597 max_width = fb_helper->fb->width;
1598 max_height = fb_helper->fb->height;
1599 bpp_sel = fb_helper->fb->bits_per_pixel;
1601 count = drm_fb_helper_probe_connector_modes(fb_helper, max_width,
1603 mutex_unlock(&fb_helper->dev->mode_config.mutex);
1605 drm_modeset_lock_all(dev);
1606 drm_setup_crtcs(fb_helper);
1607 drm_modeset_unlock_all(dev);
1608 drm_fb_helper_set_par(fb_helper->fbdev);
1612 EXPORT_SYMBOL(drm_fb_helper_hotplug_event);
1614 /* The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
1615 * but the module doesn't depend on any fb console symbols. At least
1616 * attempt to load fbcon to avoid leaving the system without a usable console.
1618 #if defined(CONFIG_FRAMEBUFFER_CONSOLE_MODULE) && !defined(CONFIG_EXPERT)
1619 static int __init drm_fb_helper_modinit(void)
1621 const char *name = "fbcon";
1622 struct module *fbcon;
1624 mutex_lock(&module_mutex);
1625 fbcon = find_module(name);
1626 mutex_unlock(&module_mutex);
1629 request_module_nowait(name);
1633 module_init(drm_fb_helper_modinit);