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  1. /*
  2.  * Copyright (c) 2006-2009 Red Hat Inc.
  3.  * Copyright (c) 2006-2008 Intel Corporation
  4.  * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
  5.  *
  6.  * DRM framebuffer helper functions
  7.  *
  8.  * Permission to use, copy, modify, distribute, and sell this software and its
  9.  * documentation for any purpose is hereby granted without fee, provided that
  10.  * the above copyright notice appear in all copies and that both that copyright
  11.  * notice and this permission notice appear in supporting documentation, and
  12.  * that the name of the copyright holders not be used in advertising or
  13.  * publicity pertaining to distribution of the software without specific,
  14.  * written prior permission.  The copyright holders make no representations
  15.  * about the suitability of this software for any purpose.  It is provided "as
  16.  * is" without express or implied warranty.
  17.  *
  18.  * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  19.  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  20.  * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  21.  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  22.  * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  23.  * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  24.  * OF THIS SOFTWARE.
  25.  *
  26.  * Authors:
  27.  *      Dave Airlie <airlied@linux.ie>
  28.  *      Jesse Barnes <jesse.barnes@intel.com>
  29.  */
  30. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  31.  
  32. #include <linux/kernel.h>
  33. #include <linux/sysrq.h>
  34. #include <linux/slab.h>
  35. #include <linux/fb.h>
  36. #include <linux/module.h>
  37. #include <drm/drmP.h>
  38. #include <drm/drm_crtc.h>
  39. #include <drm/drm_fb_helper.h>
  40. #include <drm/drm_crtc_helper.h>
  41.  
  42. MODULE_AUTHOR("David Airlie, Jesse Barnes");
  43. MODULE_DESCRIPTION("DRM KMS helper");
  44. MODULE_LICENSE("GPL and additional rights");
  45.  
  46. static LIST_HEAD(kernel_fb_helper_list);
  47.  
  48. /**
  49.  * DOC: fbdev helpers
  50.  *
  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
  54.  * interfaces.
  55.  *
  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().
  60.  *
  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.
  67.  *
  68.  * All other functions exported by the fb helper library can be used to
  69.  * implement the fbdev driver interface by the driver.
  70.  */
  71.  
  72. /**
  73.  * drm_fb_helper_single_add_all_connectors() - add all connectors to fbdev
  74.  *                                             emulation helper
  75.  * @fb_helper: fbdev initialized with drm_fb_helper_init
  76.  *
  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.
  81.  *
  82.  * Since this is part of the initial setup before the fbdev is published, no
  83.  * locking is required.
  84.  */
  85. int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
  86. {
  87.         struct drm_device *dev = fb_helper->dev;
  88.         struct drm_connector *connector;
  89.         int i;
  90.  
  91.         list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
  92.                 struct drm_fb_helper_connector *fb_helper_connector;
  93.  
  94.                 fb_helper_connector = kzalloc(sizeof(struct drm_fb_helper_connector), GFP_KERNEL);
  95.                 if (!fb_helper_connector)
  96.                         goto fail;
  97.  
  98.                 fb_helper_connector->connector = connector;
  99.                 fb_helper->connector_info[fb_helper->connector_count++] = fb_helper_connector;
  100.         }
  101.         return 0;
  102. fail:
  103.         for (i = 0; i < fb_helper->connector_count; i++) {
  104.                 kfree(fb_helper->connector_info[i]);
  105.                 fb_helper->connector_info[i] = NULL;
  106.         }
  107.         fb_helper->connector_count = 0;
  108.     return -ENOMEM;
  109. }
  110. EXPORT_SYMBOL(drm_fb_helper_single_add_all_connectors);
  111.  
  112. static void drm_fb_helper_save_lut_atomic(struct drm_crtc *crtc, struct drm_fb_helper *helper)
  113. {
  114.         uint16_t *r_base, *g_base, *b_base;
  115.         int i;
  116.  
  117.         r_base = crtc->gamma_store;
  118.         g_base = r_base + crtc->gamma_size;
  119.         b_base = g_base + crtc->gamma_size;
  120.  
  121.         for (i = 0; i < crtc->gamma_size; i++)
  122.                 helper->funcs->gamma_get(crtc, &r_base[i], &g_base[i], &b_base[i], i);
  123. }
  124.  
  125. static void drm_fb_helper_restore_lut_atomic(struct drm_crtc *crtc)
  126. {
  127.         uint16_t *r_base, *g_base, *b_base;
  128.  
  129.         if (crtc->funcs->gamma_set == NULL)
  130.                 return;
  131.  
  132.         r_base = crtc->gamma_store;
  133.         g_base = r_base + crtc->gamma_size;
  134.         b_base = g_base + crtc->gamma_size;
  135.  
  136.         crtc->funcs->gamma_set(crtc, r_base, g_base, b_base, 0, crtc->gamma_size);
  137. }
  138.  
  139.  
  140. static bool drm_fb_helper_is_bound(struct drm_fb_helper *fb_helper)
  141. {
  142.         struct drm_device *dev = fb_helper->dev;
  143.         struct drm_crtc *crtc;
  144.         int bound = 0, crtcs_bound = 0;
  145.  
  146.         list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
  147.                 if (crtc->fb)
  148.                         crtcs_bound++;
  149.                 if (crtc->fb == fb_helper->fb)
  150.                         bound++;
  151.         }
  152.  
  153.         if (bound < crtcs_bound)
  154.                 return false;
  155.         return true;
  156. }
  157.  
  158. static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode)
  159. {
  160.         struct drm_fb_helper *fb_helper = info->par;
  161.         struct drm_device *dev = fb_helper->dev;
  162.         struct drm_crtc *crtc;
  163.         struct drm_connector *connector;
  164.         int i, j;
  165.  
  166.         /*
  167.          * fbdev->blank can be called from irq context in case of a panic.
  168.          * Since we already have our own special panic handler which will
  169.          * restore the fbdev console mode completely, just bail out early.
  170.          */
  171.  
  172.         /*
  173.          * For each CRTC in this fb, turn the connectors on/off.
  174.          */
  175.         drm_modeset_lock_all(dev);
  176.         if (!drm_fb_helper_is_bound(fb_helper)) {
  177.                 drm_modeset_unlock_all(dev);
  178.                 return;
  179.         }
  180.  
  181.         for (i = 0; i < fb_helper->crtc_count; i++) {
  182.                 crtc = fb_helper->crtc_info[i].mode_set.crtc;
  183.  
  184.                 if (!crtc->enabled)
  185.                                 continue;
  186.  
  187.                 /* Walk the connectors & encoders on this fb turning them on/off */
  188.                 for (j = 0; j < fb_helper->connector_count; j++) {
  189.                         connector = fb_helper->connector_info[j]->connector;
  190.                         connector->funcs->dpms(connector, dpms_mode);
  191.                         drm_object_property_set_value(&connector->base,
  192.                                 dev->mode_config.dpms_property, dpms_mode);
  193.                 }
  194.         }
  195.         drm_modeset_unlock_all(dev);
  196. }
  197.  
  198. /**
  199.  * drm_fb_helper_blank - implementation for ->fb_blank
  200.  * @blank: desired blanking state
  201.  * @info: fbdev registered by the helper
  202.  */
  203. int drm_fb_helper_blank(int blank, struct fb_info *info)
  204. {
  205.         switch (blank) {
  206.         /* Display: On; HSync: On, VSync: On */
  207.         case FB_BLANK_UNBLANK:
  208.                 drm_fb_helper_dpms(info, DRM_MODE_DPMS_ON);
  209.                 break;
  210.         /* Display: Off; HSync: On, VSync: On */
  211.         case FB_BLANK_NORMAL:
  212.                 drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
  213.                 break;
  214.         /* Display: Off; HSync: Off, VSync: On */
  215.         case FB_BLANK_HSYNC_SUSPEND:
  216.                 drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
  217.                 break;
  218.         /* Display: Off; HSync: On, VSync: Off */
  219.         case FB_BLANK_VSYNC_SUSPEND:
  220.                 drm_fb_helper_dpms(info, DRM_MODE_DPMS_SUSPEND);
  221.                 break;
  222.         /* Display: Off; HSync: Off, VSync: Off */
  223.         case FB_BLANK_POWERDOWN:
  224.                 drm_fb_helper_dpms(info, DRM_MODE_DPMS_OFF);
  225.                 break;
  226.         }
  227.         return 0;
  228. }
  229. EXPORT_SYMBOL(drm_fb_helper_blank);
  230.  
  231. static void drm_fb_helper_crtc_free(struct drm_fb_helper *helper)
  232. {
  233.         int i;
  234.  
  235.         for (i = 0; i < helper->connector_count; i++)
  236.                 kfree(helper->connector_info[i]);
  237.         kfree(helper->connector_info);
  238.         for (i = 0; i < helper->crtc_count; i++) {
  239.                 kfree(helper->crtc_info[i].mode_set.connectors);
  240.                 if (helper->crtc_info[i].mode_set.mode)
  241.                         drm_mode_destroy(helper->dev, helper->crtc_info[i].mode_set.mode);
  242.         }
  243.         kfree(helper->crtc_info);
  244. }
  245.  
  246. /**
  247.  * drm_fb_helper_init - initialize a drm_fb_helper structure
  248.  * @dev: drm device
  249.  * @fb_helper: driver-allocated fbdev helper structure to initialize
  250.  * @crtc_count: maximum number of crtcs to support in this fbdev emulation
  251.  * @max_conn_count: max connector count
  252.  *
  253.  * This allocates the structures for the fbdev helper with the given limits.
  254.  * Note that this won't yet touch the hardware (through the driver interfaces)
  255.  * nor register the fbdev. This is only done in drm_fb_helper_initial_config()
  256.  * to allow driver writes more control over the exact init sequence.
  257.  *
  258.  * Drivers must set fb_helper->funcs before calling
  259.  * drm_fb_helper_initial_config().
  260.  *
  261.  * RETURNS:
  262.  * Zero if everything went ok, nonzero otherwise.
  263.  */
  264. int drm_fb_helper_init(struct drm_device *dev,
  265.                        struct drm_fb_helper *fb_helper,
  266.                        int crtc_count, int max_conn_count)
  267. {
  268.         struct drm_crtc *crtc;
  269.         int i;
  270.  
  271.         fb_helper->dev = dev;
  272.  
  273.         INIT_LIST_HEAD(&fb_helper->kernel_fb_list);
  274.  
  275.         fb_helper->crtc_info = kcalloc(crtc_count, sizeof(struct drm_fb_helper_crtc), GFP_KERNEL);
  276.         if (!fb_helper->crtc_info)
  277.                 return -ENOMEM;
  278.  
  279.         fb_helper->crtc_count = crtc_count;
  280.         fb_helper->connector_info = kcalloc(dev->mode_config.num_connector, sizeof(struct drm_fb_helper_connector *), GFP_KERNEL);
  281.         if (!fb_helper->connector_info) {
  282.                 kfree(fb_helper->crtc_info);
  283.                 return -ENOMEM;
  284.         }
  285.         fb_helper->connector_count = 0;
  286.  
  287.         for (i = 0; i < crtc_count; i++) {
  288.                 fb_helper->crtc_info[i].mode_set.connectors =
  289.                         kcalloc(max_conn_count,
  290.                                 sizeof(struct drm_connector *),
  291.                                 GFP_KERNEL);
  292.  
  293.                 if (!fb_helper->crtc_info[i].mode_set.connectors)
  294.                         goto out_free;
  295.                 fb_helper->crtc_info[i].mode_set.num_connectors = 0;
  296.         }
  297.  
  298.         i = 0;
  299.         list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
  300.                 fb_helper->crtc_info[i].mode_set.crtc = crtc;
  301.                 i++;
  302.         }
  303.  
  304.         return 0;
  305. out_free:
  306.         drm_fb_helper_crtc_free(fb_helper);
  307.         return -ENOMEM;
  308. }
  309. EXPORT_SYMBOL(drm_fb_helper_init);
  310.  
  311. static int setcolreg(struct drm_crtc *crtc, u16 red, u16 green,
  312.                      u16 blue, u16 regno, struct fb_info *info)
  313. {
  314.         struct drm_fb_helper *fb_helper = info->par;
  315.         struct drm_framebuffer *fb = fb_helper->fb;
  316.         int pindex;
  317.  
  318.         if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
  319.                 u32 *palette;
  320.                 u32 value;
  321.                 /* place color in psuedopalette */
  322.                 if (regno > 16)
  323.                         return -EINVAL;
  324.                 palette = (u32 *)info->pseudo_palette;
  325.                 red >>= (16 - info->var.red.length);
  326.                 green >>= (16 - info->var.green.length);
  327.                 blue >>= (16 - info->var.blue.length);
  328.                 value = (red << info->var.red.offset) |
  329.                         (green << info->var.green.offset) |
  330.                         (blue << info->var.blue.offset);
  331.                 if (info->var.transp.length > 0) {
  332.                         u32 mask = (1 << info->var.transp.length) - 1;
  333.                         mask <<= info->var.transp.offset;
  334.                         value |= mask;
  335.                 }
  336.                 palette[regno] = value;
  337.                 return 0;
  338.         }
  339.  
  340.         pindex = regno;
  341.  
  342.         if (fb->bits_per_pixel == 16) {
  343.                 pindex = regno << 3;
  344.  
  345.                 if (fb->depth == 16 && regno > 63)
  346.                         return -EINVAL;
  347.                 if (fb->depth == 15 && regno > 31)
  348.                         return -EINVAL;
  349.  
  350.                 if (fb->depth == 16) {
  351.                         u16 r, g, b;
  352.                         int i;
  353.                         if (regno < 32) {
  354.                                 for (i = 0; i < 8; i++)
  355.                                         fb_helper->funcs->gamma_set(crtc, red,
  356.                                                 green, blue, pindex + i);
  357.                         }
  358.  
  359.                         fb_helper->funcs->gamma_get(crtc, &r,
  360.                                                     &g, &b,
  361.                                                     pindex >> 1);
  362.  
  363.                         for (i = 0; i < 4; i++)
  364.                                 fb_helper->funcs->gamma_set(crtc, r,
  365.                                                             green, b,
  366.                                                             (pindex >> 1) + i);
  367.                 }
  368.         }
  369.  
  370.         if (fb->depth != 16)
  371.                 fb_helper->funcs->gamma_set(crtc, red, green, blue, pindex);
  372.         return 0;
  373. }
  374.  
  375. /**
  376.  * drm_fb_helper_setcmap - implementation for ->fb_setcmap
  377.  * @cmap: cmap to set
  378.  * @info: fbdev registered by the helper
  379.  */
  380. int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
  381. {
  382.         struct drm_fb_helper *fb_helper = info->par;
  383.         struct drm_crtc_helper_funcs *crtc_funcs;
  384.         u16 *red, *green, *blue, *transp;
  385.         struct drm_crtc *crtc;
  386.         int i, j, rc = 0;
  387.         int start;
  388.  
  389.                 for (i = 0; i < fb_helper->crtc_count; i++) {
  390.                 crtc = fb_helper->crtc_info[i].mode_set.crtc;
  391.                 crtc_funcs = crtc->helper_private;
  392.  
  393.                 red = cmap->red;
  394.                 green = cmap->green;
  395.                 blue = cmap->blue;
  396.                 transp = cmap->transp;
  397.                 start = cmap->start;
  398.  
  399.                 for (j = 0; j < cmap->len; j++) {
  400.                         u16 hred, hgreen, hblue, htransp = 0xffff;
  401.  
  402.                         hred = *red++;
  403.                         hgreen = *green++;
  404.                         hblue = *blue++;
  405.  
  406.                         if (transp)
  407.                                 htransp = *transp++;
  408.  
  409.                         rc = setcolreg(crtc, hred, hgreen, hblue, start++, info);
  410.                         if (rc)
  411.                                 return rc;
  412.                 }
  413.                 crtc_funcs->load_lut(crtc);
  414.         }
  415.         return rc;
  416. }
  417. EXPORT_SYMBOL(drm_fb_helper_setcmap);
  418.  
  419. /**
  420.  * drm_fb_helper_check_var - implementation for ->fb_check_var
  421.  * @var: screeninfo to check
  422.  * @info: fbdev registered by the helper
  423.  */
  424. int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
  425.                             struct fb_info *info)
  426. {
  427.         struct drm_fb_helper *fb_helper = info->par;
  428.         struct drm_framebuffer *fb = fb_helper->fb;
  429.         int depth;
  430.  
  431.         if (var->pixclock != 0 || in_dbg_master())
  432.                 return -EINVAL;
  433.  
  434.         /* Need to resize the fb object !!! */
  435.         if (var->bits_per_pixel > fb->bits_per_pixel ||
  436.             var->xres > fb->width || var->yres > fb->height ||
  437.             var->xres_virtual > fb->width || var->yres_virtual > fb->height) {
  438.                 DRM_DEBUG("fb userspace requested width/height/bpp is greater than current fb "
  439.                           "request %dx%d-%d (virtual %dx%d) > %dx%d-%d\n",
  440.                           var->xres, var->yres, var->bits_per_pixel,
  441.                           var->xres_virtual, var->yres_virtual,
  442.                           fb->width, fb->height, fb->bits_per_pixel);
  443.                 return -EINVAL;
  444.         }
  445.  
  446.         switch (var->bits_per_pixel) {
  447.         case 16:
  448.                 depth = (var->green.length == 6) ? 16 : 15;
  449.                 break;
  450.         case 32:
  451.                 depth = (var->transp.length > 0) ? 32 : 24;
  452.                 break;
  453.         default:
  454.                 depth = var->bits_per_pixel;
  455.                 break;
  456.         }
  457.  
  458.         switch (depth) {
  459.         case 8:
  460.                 var->red.offset = 0;
  461.                 var->green.offset = 0;
  462.                 var->blue.offset = 0;
  463.                 var->red.length = 8;
  464.                 var->green.length = 8;
  465.                 var->blue.length = 8;
  466.                 var->transp.length = 0;
  467.                 var->transp.offset = 0;
  468.                 break;
  469.         case 15:
  470.                 var->red.offset = 10;
  471.                 var->green.offset = 5;
  472.                 var->blue.offset = 0;
  473.                 var->red.length = 5;
  474.                 var->green.length = 5;
  475.                 var->blue.length = 5;
  476.                 var->transp.length = 1;
  477.                 var->transp.offset = 15;
  478.                 break;
  479.         case 16:
  480.                 var->red.offset = 11;
  481.                 var->green.offset = 5;
  482.                 var->blue.offset = 0;
  483.                 var->red.length = 5;
  484.                 var->green.length = 6;
  485.                 var->blue.length = 5;
  486.                 var->transp.length = 0;
  487.                 var->transp.offset = 0;
  488.                 break;
  489.         case 24:
  490.                 var->red.offset = 16;
  491.                 var->green.offset = 8;
  492.                 var->blue.offset = 0;
  493.                 var->red.length = 8;
  494.                 var->green.length = 8;
  495.                 var->blue.length = 8;
  496.                 var->transp.length = 0;
  497.                 var->transp.offset = 0;
  498.                 break;
  499.         case 32:
  500.                 var->red.offset = 16;
  501.                 var->green.offset = 8;
  502.                 var->blue.offset = 0;
  503.                 var->red.length = 8;
  504.                 var->green.length = 8;
  505.                 var->blue.length = 8;
  506.                 var->transp.length = 8;
  507.                 var->transp.offset = 24;
  508.                 break;
  509.         default:
  510.                 return -EINVAL;
  511.         }
  512.         return 0;
  513. }
  514. EXPORT_SYMBOL(drm_fb_helper_check_var);
  515.  
  516. /**
  517.  * drm_fb_helper_set_par - implementation for ->fb_set_par
  518.  * @info: fbdev registered by the helper
  519.  *
  520.  * This will let fbcon do the mode init and is called at initialization time by
  521.  * the fbdev core when registering the driver, and later on through the hotplug
  522.  * callback.
  523.  */
  524. int drm_fb_helper_set_par(struct fb_info *info)
  525. {
  526.         struct drm_fb_helper *fb_helper = info->par;
  527.         struct drm_device *dev = fb_helper->dev;
  528.         struct fb_var_screeninfo *var = &info->var;
  529.         int ret;
  530.         int i;
  531.  
  532.         if (var->pixclock != 0) {
  533.                 DRM_ERROR("PIXEL CLOCK SET\n");
  534.                 return -EINVAL;
  535.         }
  536.  
  537.         drm_modeset_lock_all(dev);
  538.                 for (i = 0; i < fb_helper->crtc_count; i++) {
  539.                 ret = drm_mode_set_config_internal(&fb_helper->crtc_info[i].mode_set);
  540.                 if (ret) {
  541.                         drm_modeset_unlock_all(dev);
  542.                                 return ret;
  543.                 }
  544.         }
  545.         drm_modeset_unlock_all(dev);
  546.  
  547.         if (fb_helper->delayed_hotplug) {
  548.                 fb_helper->delayed_hotplug = false;
  549.                 drm_fb_helper_hotplug_event(fb_helper);
  550.         }
  551.         return 0;
  552. }
  553. EXPORT_SYMBOL(drm_fb_helper_set_par);
  554.  
  555. /**
  556.  * drm_fb_helper_pan_display - implementation for ->fb_pan_display
  557.  * @var: updated screen information
  558.  * @info: fbdev registered by the helper
  559.  */
  560. int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
  561.                               struct fb_info *info)
  562. {
  563.         struct drm_fb_helper *fb_helper = info->par;
  564.         struct drm_device *dev = fb_helper->dev;
  565.         struct drm_mode_set *modeset;
  566.         struct drm_crtc *crtc;
  567.         int ret = 0;
  568.         int i;
  569.  
  570.         drm_modeset_lock_all(dev);
  571.         if (!drm_fb_helper_is_bound(fb_helper)) {
  572.                 drm_modeset_unlock_all(dev);
  573.                 return -EBUSY;
  574.         }
  575.  
  576.                 for (i = 0; i < fb_helper->crtc_count; i++) {
  577.                 crtc = fb_helper->crtc_info[i].mode_set.crtc;
  578.  
  579.                 modeset = &fb_helper->crtc_info[i].mode_set;
  580.  
  581.                 modeset->x = var->xoffset;
  582.                 modeset->y = var->yoffset;
  583.  
  584.                 if (modeset->num_connectors) {
  585.                         ret = drm_mode_set_config_internal(modeset);
  586.                         if (!ret) {
  587.                                 info->var.xoffset = var->xoffset;
  588.                                 info->var.yoffset = var->yoffset;
  589.                         }
  590.                 }
  591.         }
  592.         drm_modeset_unlock_all(dev);
  593.         return ret;
  594. }
  595. EXPORT_SYMBOL(drm_fb_helper_pan_display);
  596.  
  597. /*
  598.  * Allocates the backing storage and sets up the fbdev info structure through
  599.  * the ->fb_probe callback and then registers the fbdev and sets up the panic
  600.  * notifier.
  601.  */
  602. static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
  603.                                   int preferred_bpp)
  604. {
  605.         int ret = 0;
  606.         int crtc_count = 0;
  607.         int i;
  608.         struct fb_info *info;
  609.         struct drm_fb_helper_surface_size sizes;
  610.         int gamma_size = 0;
  611.  
  612.         memset(&sizes, 0, sizeof(struct drm_fb_helper_surface_size));
  613.         sizes.surface_depth = 24;
  614.         sizes.surface_bpp = 32;
  615.         sizes.fb_width = (unsigned)-1;
  616.         sizes.fb_height = (unsigned)-1;
  617.  
  618.         /* if driver picks 8 or 16 by default use that
  619.            for both depth/bpp */
  620.         if (preferred_bpp != sizes.surface_bpp)
  621.                 sizes.surface_depth = sizes.surface_bpp = preferred_bpp;
  622.  
  623.         /* first up get a count of crtcs now in use and new min/maxes width/heights */
  624.         for (i = 0; i < fb_helper->connector_count; i++) {
  625.                 struct drm_fb_helper_connector *fb_helper_conn = fb_helper->connector_info[i];
  626.                 struct drm_cmdline_mode *cmdline_mode;
  627.  
  628.                 cmdline_mode = &fb_helper_conn->cmdline_mode;
  629.  
  630.                 if (cmdline_mode->bpp_specified) {
  631.                         switch (cmdline_mode->bpp) {
  632.                         case 8:
  633.                                 sizes.surface_depth = sizes.surface_bpp = 8;
  634.                                 break;
  635.                         case 15:
  636.                                 sizes.surface_depth = 15;
  637.                                 sizes.surface_bpp = 16;
  638.                                 break;
  639.                         case 16:
  640.                                 sizes.surface_depth = sizes.surface_bpp = 16;
  641.                                 break;
  642.                         case 24:
  643.                                 sizes.surface_depth = sizes.surface_bpp = 24;
  644.                                 break;
  645.                         case 32:
  646.     sizes.surface_depth = 24;
  647.     sizes.surface_bpp = 32;
  648.                                 break;
  649.                         }
  650.                         break;
  651.                 }
  652.         }
  653.  
  654.         crtc_count = 0;
  655.         for (i = 0; i < fb_helper->crtc_count; i++) {
  656.                 struct drm_display_mode *desired_mode;
  657.                 desired_mode = fb_helper->crtc_info[i].desired_mode;
  658.  
  659.                 if (desired_mode) {
  660.                         if (gamma_size == 0)
  661.                                 gamma_size = fb_helper->crtc_info[i].mode_set.crtc->gamma_size;
  662.                         if (desired_mode->hdisplay < sizes.fb_width)
  663.                                 sizes.fb_width = desired_mode->hdisplay;
  664.                         if (desired_mode->vdisplay < sizes.fb_height)
  665.                                 sizes.fb_height = desired_mode->vdisplay;
  666.                         if (desired_mode->hdisplay > sizes.surface_width)
  667.                                 sizes.surface_width = desired_mode->hdisplay;
  668.                         if (desired_mode->vdisplay > sizes.surface_height)
  669.                                 sizes.surface_height = desired_mode->vdisplay;
  670.                         crtc_count++;
  671.                 }
  672.         }
  673.  
  674.         if (crtc_count == 0 || sizes.fb_width == -1 || sizes.fb_height == -1) {
  675.                 /* hmm everyone went away - assume VGA cable just fell out
  676.                    and will come back later. */
  677.                 DRM_INFO("Cannot find any crtc or sizes - going 1024x768\n");
  678.                 sizes.fb_width = sizes.surface_width = 1024;
  679.                 sizes.fb_height = sizes.surface_height = 768;
  680.         }
  681.  
  682.         /* push down into drivers */
  683.         ret = (*fb_helper->funcs->fb_probe)(fb_helper, &sizes);
  684.         if (ret < 0)
  685.                 return ret;
  686.  
  687.         info = fb_helper->fbdev;
  688.  
  689.         /*
  690.          * Set the fb pointer - usually drm_setup_crtcs does this for hotplug
  691.          * events, but at init time drm_setup_crtcs needs to be called before
  692.          * the fb is allocated (since we need to figure out the desired size of
  693.          * the fb before we can allocate it ...). Hence we need to fix things up
  694.          * here again.
  695.          */
  696.         for (i = 0; i < fb_helper->crtc_count; i++)
  697.                 if (fb_helper->crtc_info[i].mode_set.num_connectors)
  698.                 fb_helper->crtc_info[i].mode_set.fb = fb_helper->fb;
  699.  
  700.  
  701.                 info->var.pixclock = 0;
  702.  
  703.         list_add(&fb_helper->kernel_fb_list, &kernel_fb_helper_list);
  704.  
  705.         return 0;
  706. }
  707.  
  708. /**
  709.  * drm_fb_helper_fill_fix - initializes fixed fbdev information
  710.  * @info: fbdev registered by the helper
  711.  * @pitch: desired pitch
  712.  * @depth: desired depth
  713.  *
  714.  * Helper to fill in the fixed fbdev information useful for a non-accelerated
  715.  * fbdev emulations. Drivers which support acceleration methods which impose
  716.  * additional constraints need to set up their own limits.
  717.  *
  718.  * Drivers should call this (or their equivalent setup code) from their
  719.  * ->fb_probe callback.
  720.  */
  721. void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
  722.                             uint32_t depth)
  723. {
  724.         info->fix.type = FB_TYPE_PACKED_PIXELS;
  725.         info->fix.visual = depth == 8 ? FB_VISUAL_PSEUDOCOLOR :
  726.                 FB_VISUAL_TRUECOLOR;
  727.         info->fix.mmio_start = 0;
  728.         info->fix.mmio_len = 0;
  729.         info->fix.type_aux = 0;
  730.         info->fix.xpanstep = 1; /* doing it in hw */
  731.         info->fix.ypanstep = 1; /* doing it in hw */
  732.         info->fix.ywrapstep = 0;
  733.         info->fix.accel = FB_ACCEL_NONE;
  734.         info->fix.type_aux = 0;
  735.  
  736.         info->fix.line_length = pitch;
  737.         return;
  738. }
  739. EXPORT_SYMBOL(drm_fb_helper_fill_fix);
  740.  
  741. /**
  742.  * drm_fb_helper_fill_var - initalizes variable fbdev information
  743.  * @info: fbdev instance to set up
  744.  * @fb_helper: fb helper instance to use as template
  745.  * @fb_width: desired fb width
  746.  * @fb_height: desired fb height
  747.  *
  748.  * Sets up the variable fbdev metainformation from the given fb helper instance
  749.  * and the drm framebuffer allocated in fb_helper->fb.
  750.  *
  751.  * Drivers should call this (or their equivalent setup code) from their
  752.  * ->fb_probe callback after having allocated the fbdev backing
  753.  * storage framebuffer.
  754.  */
  755. void drm_fb_helper_fill_var(struct fb_info *info, struct drm_fb_helper *fb_helper,
  756.                             uint32_t fb_width, uint32_t fb_height)
  757. {
  758.         struct drm_framebuffer *fb = fb_helper->fb;
  759.         info->pseudo_palette = fb_helper->pseudo_palette;
  760.         info->var.xres_virtual = fb->width;
  761.         info->var.yres_virtual = fb->height;
  762.         info->var.bits_per_pixel = fb->bits_per_pixel;
  763.         info->var.accel_flags = FB_ACCELF_TEXT;
  764.         info->var.xoffset = 0;
  765.         info->var.yoffset = 0;
  766.         info->var.activate = FB_ACTIVATE_NOW;
  767.         info->var.height = -1;
  768.         info->var.width = -1;
  769.  
  770.         switch (fb->depth) {
  771.         case 8:
  772.                 info->var.red.offset = 0;
  773.                 info->var.green.offset = 0;
  774.                 info->var.blue.offset = 0;
  775.                 info->var.red.length = 8; /* 8bit DAC */
  776.                 info->var.green.length = 8;
  777.                 info->var.blue.length = 8;
  778.                 info->var.transp.offset = 0;
  779.                 info->var.transp.length = 0;
  780.                 break;
  781.         case 15:
  782.                 info->var.red.offset = 10;
  783.                 info->var.green.offset = 5;
  784.                 info->var.blue.offset = 0;
  785.                 info->var.red.length = 5;
  786.                 info->var.green.length = 5;
  787.                 info->var.blue.length = 5;
  788.                 info->var.transp.offset = 15;
  789.                 info->var.transp.length = 1;
  790.                 break;
  791.         case 16:
  792.                 info->var.red.offset = 11;
  793.                 info->var.green.offset = 5;
  794.                 info->var.blue.offset = 0;
  795.                 info->var.red.length = 5;
  796.                 info->var.green.length = 6;
  797.                 info->var.blue.length = 5;
  798.                 info->var.transp.offset = 0;
  799.                 break;
  800.         case 24:
  801.                 info->var.red.offset = 16;
  802.                 info->var.green.offset = 8;
  803.                 info->var.blue.offset = 0;
  804.                 info->var.red.length = 8;
  805.                 info->var.green.length = 8;
  806.                 info->var.blue.length = 8;
  807.                 info->var.transp.offset = 0;
  808.                 info->var.transp.length = 0;
  809.                 break;
  810.         case 32:
  811.                 info->var.red.offset = 16;
  812.                 info->var.green.offset = 8;
  813.                 info->var.blue.offset = 0;
  814.                 info->var.red.length = 8;
  815.                 info->var.green.length = 8;
  816.                 info->var.blue.length = 8;
  817.                 info->var.transp.offset = 24;
  818.                 info->var.transp.length = 8;
  819.                 break;
  820.         default:
  821.                 break;
  822.         }
  823.  
  824.         info->var.xres = fb_width;
  825.         info->var.yres = fb_height;
  826. }
  827. EXPORT_SYMBOL(drm_fb_helper_fill_var);
  828.  
  829. static int drm_fb_helper_probe_connector_modes(struct drm_fb_helper *fb_helper,
  830.                                                uint32_t maxX,
  831.                                                uint32_t maxY)
  832. {
  833.         struct drm_connector *connector;
  834.         int count = 0;
  835.         int i;
  836.  
  837.         for (i = 0; i < fb_helper->connector_count; i++) {
  838.                 connector = fb_helper->connector_info[i]->connector;
  839.                 count += connector->funcs->fill_modes(connector, maxX, maxY);
  840.         }
  841.  
  842.         return count;
  843. }
  844.  
  845. static struct drm_display_mode *drm_has_preferred_mode(struct drm_fb_helper_connector *fb_connector, int width, int height)
  846. {
  847.         struct drm_display_mode *mode;
  848.  
  849.         list_for_each_entry(mode, &fb_connector->connector->modes, head) {
  850.                 if (drm_mode_width(mode) > width ||
  851.                     drm_mode_height(mode) > height)
  852.                         continue;
  853.                 if (mode->type & DRM_MODE_TYPE_PREFERRED)
  854.                         return mode;
  855.         }
  856.         return NULL;
  857. }
  858.  
  859. static bool drm_has_cmdline_mode(struct drm_fb_helper_connector *fb_connector)
  860. {
  861.         struct drm_cmdline_mode *cmdline_mode;
  862.         cmdline_mode = &fb_connector->cmdline_mode;
  863.         return cmdline_mode->specified;
  864. }
  865.  
  866.  
  867. static bool drm_connector_enabled(struct drm_connector *connector, bool strict)
  868. {
  869.         bool enable;
  870.  
  871.         if (strict)
  872.                 enable = connector->status == connector_status_connected;
  873.         else
  874.                 enable = connector->status != connector_status_disconnected;
  875.  
  876.         return enable;
  877. }
  878.  
  879. static void drm_enable_connectors(struct drm_fb_helper *fb_helper,
  880.                                   bool *enabled)
  881. {
  882.         bool any_enabled = false;
  883.         struct drm_connector *connector;
  884.         int i = 0;
  885.  
  886.         for (i = 0; i < fb_helper->connector_count; i++) {
  887.                 connector = fb_helper->connector_info[i]->connector;
  888.                 enabled[i] = drm_connector_enabled(connector, true);
  889.                 DRM_DEBUG_KMS("connector %d enabled? %s\n", connector->base.id,
  890.                           enabled[i] ? "yes" : "no");
  891.                 any_enabled |= enabled[i];
  892.         }
  893.  
  894.         if (any_enabled)
  895.                 return;
  896.  
  897.         for (i = 0; i < fb_helper->connector_count; i++) {
  898.                 connector = fb_helper->connector_info[i]->connector;
  899.                 enabled[i] = drm_connector_enabled(connector, false);
  900.         }
  901. }
  902.  
  903.  
  904. static bool drm_target_preferred(struct drm_fb_helper *fb_helper,
  905.                                  struct drm_display_mode **modes,
  906.                                  bool *enabled, int width, int height)
  907. {
  908.         struct drm_fb_helper_connector *fb_helper_conn;
  909.         int i;
  910.  
  911.         for (i = 0; i < fb_helper->connector_count; i++) {
  912.                 fb_helper_conn = fb_helper->connector_info[i];
  913.  
  914.                 if (enabled[i] == false)
  915.                         continue;
  916.  
  917.                 DRM_DEBUG_KMS("looking for cmdline mode on connector %d\n",
  918.                               fb_helper_conn->connector->base.id);
  919.  
  920.                 /* got for command line mode first */
  921. //       modes[i] = drm_pick_cmdline_mode(fb_helper_conn, width, height);
  922.  
  923.         modes[i] = NULL;
  924.  
  925.                 if (!modes[i]) {
  926.                         DRM_DEBUG_KMS("looking for preferred mode on connector %d\n",
  927.                                       fb_helper_conn->connector->base.id);
  928.                         modes[i] = drm_has_preferred_mode(fb_helper_conn, width, height);
  929.                 }
  930.                 /* No preferred modes, pick one off the list */
  931.                 if (!modes[i] && !list_empty(&fb_helper_conn->connector->modes)) {
  932.                         list_for_each_entry(modes[i], &fb_helper_conn->connector->modes, head)
  933.                                 break;
  934.                 }
  935.                 DRM_DEBUG_KMS("found mode %s\n", modes[i] ? modes[i]->name :
  936.                           "none");
  937.         }
  938.         return true;
  939. }
  940.  
  941. static int drm_pick_crtcs(struct drm_fb_helper *fb_helper,
  942.                           struct drm_fb_helper_crtc **best_crtcs,
  943.                           struct drm_display_mode **modes,
  944.                           int n, int width, int height)
  945. {
  946.         int c, o;
  947.         struct drm_device *dev = fb_helper->dev;
  948.         struct drm_connector *connector;
  949.         struct drm_connector_helper_funcs *connector_funcs;
  950.         struct drm_encoder *encoder;
  951.         struct drm_fb_helper_crtc *best_crtc;
  952.         int my_score, best_score, score;
  953.         struct drm_fb_helper_crtc **crtcs, *crtc;
  954.         struct drm_fb_helper_connector *fb_helper_conn;
  955.  
  956.         if (n == fb_helper->connector_count)
  957.                 return 0;
  958.  
  959.         fb_helper_conn = fb_helper->connector_info[n];
  960.         connector = fb_helper_conn->connector;
  961.  
  962.         best_crtcs[n] = NULL;
  963.         best_crtc = NULL;
  964.         best_score = drm_pick_crtcs(fb_helper, best_crtcs, modes, n+1, width, height);
  965.         if (modes[n] == NULL)
  966.                 return best_score;
  967.  
  968.         crtcs = kzalloc(dev->mode_config.num_connector *
  969.                         sizeof(struct drm_fb_helper_crtc *), GFP_KERNEL);
  970.         if (!crtcs)
  971.                 return best_score;
  972.  
  973.         my_score = 1;
  974.         if (connector->status == connector_status_connected)
  975.                 my_score++;
  976.         if (drm_has_cmdline_mode(fb_helper_conn))
  977.                 my_score++;
  978.         if (drm_has_preferred_mode(fb_helper_conn, width, height))
  979.                 my_score++;
  980.  
  981.         connector_funcs = connector->helper_private;
  982.         encoder = connector_funcs->best_encoder(connector);
  983.         if (!encoder)
  984.                 goto out;
  985.  
  986.         /* select a crtc for this connector and then attempt to configure
  987.            remaining connectors */
  988.         for (c = 0; c < fb_helper->crtc_count; c++) {
  989.                 crtc = &fb_helper->crtc_info[c];
  990.  
  991.                 if ((encoder->possible_crtcs & (1 << c)) == 0)
  992.                         continue;
  993.  
  994.                 for (o = 0; o < n; o++)
  995.                         if (best_crtcs[o] == crtc)
  996.                                 break;
  997.  
  998.                 if (o < n) {
  999.                         /* ignore cloning unless only a single crtc */
  1000.                         if (fb_helper->crtc_count > 1)
  1001.                                 continue;
  1002.  
  1003.                         if (!drm_mode_equal(modes[o], modes[n]))
  1004.                                 continue;
  1005.                 }
  1006.  
  1007.                 crtcs[n] = crtc;
  1008.                 memcpy(crtcs, best_crtcs, n * sizeof(struct drm_fb_helper_crtc *));
  1009.                 score = my_score + drm_pick_crtcs(fb_helper, crtcs, modes, n + 1,
  1010.                                                   width, height);
  1011.                 if (score > best_score) {
  1012.                         best_crtc = crtc;
  1013.                         best_score = score;
  1014.                         memcpy(best_crtcs, crtcs,
  1015.                                dev->mode_config.num_connector *
  1016.                                sizeof(struct drm_fb_helper_crtc *));
  1017.                 }
  1018.         }
  1019. out:
  1020.         kfree(crtcs);
  1021.         return best_score;
  1022. }
  1023.  
  1024. static void drm_setup_crtcs(struct drm_fb_helper *fb_helper)
  1025. {
  1026.         struct drm_device *dev = fb_helper->dev;
  1027.         struct drm_fb_helper_crtc **crtcs;
  1028.         struct drm_display_mode **modes;
  1029.         struct drm_mode_set *modeset;
  1030.         bool *enabled;
  1031.         int width, height;
  1032.         int i, ret;
  1033.  
  1034.         DRM_DEBUG_KMS("\n");
  1035.  
  1036.         width = dev->mode_config.max_width;
  1037.         height = dev->mode_config.max_height;
  1038.  
  1039.         crtcs = kcalloc(dev->mode_config.num_connector,
  1040.                         sizeof(struct drm_fb_helper_crtc *), GFP_KERNEL);
  1041.         modes = kcalloc(dev->mode_config.num_connector,
  1042.                         sizeof(struct drm_display_mode *), GFP_KERNEL);
  1043.         enabled = kcalloc(dev->mode_config.num_connector,
  1044.                           sizeof(bool), GFP_KERNEL);
  1045.         if (!crtcs || !modes || !enabled) {
  1046.                 DRM_ERROR("Memory allocation failed\n");
  1047.                 goto out;
  1048.         }
  1049.  
  1050.  
  1051.         drm_enable_connectors(fb_helper, enabled);
  1052.  
  1053.     //ret = drm_target_cloned(fb_helper, modes, enabled, width, height);
  1054.  
  1055.     ret = 0;
  1056.  
  1057.         if (!ret) {
  1058.                 ret = drm_target_preferred(fb_helper, modes, enabled, width, height);
  1059.                 if (!ret)
  1060.                         DRM_ERROR("Unable to find initial modes\n");
  1061.         }
  1062.  
  1063.         DRM_DEBUG_KMS("picking CRTCs for %dx%d config\n", width, height);
  1064.  
  1065.         drm_pick_crtcs(fb_helper, crtcs, modes, 0, width, height);
  1066.  
  1067.         /* need to set the modesets up here for use later */
  1068.         /* fill out the connector<->crtc mappings into the modesets */
  1069.         for (i = 0; i < fb_helper->crtc_count; i++) {
  1070.                 modeset = &fb_helper->crtc_info[i].mode_set;
  1071.                 modeset->num_connectors = 0;
  1072.                 modeset->fb = NULL;
  1073.         }
  1074.  
  1075.         for (i = 0; i < fb_helper->connector_count; i++) {
  1076.                 struct drm_display_mode *mode = modes[i];
  1077.                 struct drm_fb_helper_crtc *fb_crtc = crtcs[i];
  1078.                 modeset = &fb_crtc->mode_set;
  1079.  
  1080.                 if (mode && fb_crtc) {
  1081.                         DRM_DEBUG_KMS("desired mode %s set on crtc %d\n",
  1082.                                       mode->name, fb_crtc->mode_set.crtc->base.id);
  1083.                         fb_crtc->desired_mode = mode;
  1084.                         if (modeset->mode)
  1085.                                 drm_mode_destroy(dev, modeset->mode);
  1086.                         modeset->mode = drm_mode_duplicate(dev,
  1087.                                                            fb_crtc->desired_mode);
  1088.                         modeset->connectors[modeset->num_connectors++] = fb_helper->connector_info[i]->connector;
  1089.                         modeset->fb = fb_helper->fb;
  1090.                 }
  1091.         }
  1092.  
  1093.         /* Clear out any old modes if there are no more connected outputs. */
  1094.         for (i = 0; i < fb_helper->crtc_count; i++) {
  1095.                 modeset = &fb_helper->crtc_info[i].mode_set;
  1096.                 if (modeset->num_connectors == 0) {
  1097.                         BUG_ON(modeset->fb);
  1098.                         BUG_ON(modeset->num_connectors);
  1099.                         if (modeset->mode)
  1100.                                 drm_mode_destroy(dev, modeset->mode);
  1101.                         modeset->mode = NULL;
  1102.                 }
  1103.         }
  1104. out:
  1105.         kfree(crtcs);
  1106.         kfree(modes);
  1107.         kfree(enabled);
  1108. }
  1109.  
  1110. /**
  1111.  * drm_fb_helper_initial_config - setup a sane initial connector configuration
  1112.  * @fb_helper: fb_helper device struct
  1113.  * @bpp_sel: bpp value to use for the framebuffer configuration
  1114.  *
  1115.  * Scans the CRTCs and connectors and tries to put together an initial setup.
  1116.  * At the moment, this is a cloned configuration across all heads with
  1117.  * a new framebuffer object as the backing store.
  1118.  *
  1119.  * Note that this also registers the fbdev and so allows userspace to call into
  1120.  * the driver through the fbdev interfaces.
  1121.  *
  1122.  * This function will call down into the ->fb_probe callback to let
  1123.  * the driver allocate and initialize the fbdev info structure and the drm
  1124.  * framebuffer used to back the fbdev. drm_fb_helper_fill_var() and
  1125.  * drm_fb_helper_fill_fix() are provided as helpers to setup simple default
  1126.  * values for the fbdev info structure.
  1127.  *
  1128.  * RETURNS:
  1129.  * Zero if everything went ok, nonzero otherwise.
  1130.  */
  1131. bool drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper, int bpp_sel)
  1132. {
  1133.         struct drm_device *dev = fb_helper->dev;
  1134.         int count = 0;
  1135.  
  1136. //   drm_fb_helper_parse_command_line(fb_helper);
  1137.  
  1138.         count = drm_fb_helper_probe_connector_modes(fb_helper,
  1139.                                                     dev->mode_config.max_width,
  1140.                                                     dev->mode_config.max_height);
  1141.         /*
  1142.          * we shouldn't end up with no modes here.
  1143.          */
  1144.         if (count == 0)
  1145.                 dev_info(fb_helper->dev->dev, "No connectors reported connected with modes\n");
  1146.  
  1147.         drm_setup_crtcs(fb_helper);
  1148.  
  1149.         return drm_fb_helper_single_fb_probe(fb_helper, bpp_sel);
  1150. }
  1151. EXPORT_SYMBOL(drm_fb_helper_initial_config);
  1152.  
  1153. /**
  1154.  * drm_fb_helper_hotplug_event - respond to a hotplug notification by
  1155.  *                               probing all the outputs attached to the fb
  1156.  * @fb_helper: the drm_fb_helper
  1157.  *
  1158.  * Scan the connectors attached to the fb_helper and try to put together a
  1159.  * setup after *notification of a change in output configuration.
  1160.  *
  1161.  * Called at runtime, takes the mode config locks to be able to check/change the
  1162.  * modeset configuration. Must be run from process context (which usually means
  1163.  * either the output polling work or a work item launched from the driver's
  1164.  * hotplug interrupt).
  1165.  *
  1166.  * Note that the driver must ensure that this is only called _after_ the fb has
  1167.  * been fully set up, i.e. after the call to drm_fb_helper_initial_config.
  1168.  *
  1169.  * RETURNS:
  1170.  * 0 on success and a non-zero error code otherwise.
  1171.  */
  1172. int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
  1173. {
  1174.         struct drm_device *dev = fb_helper->dev;
  1175.         int count = 0;
  1176.         u32 max_width, max_height, bpp_sel;
  1177.  
  1178.         if (!fb_helper->fb)
  1179.                 return 0;
  1180.  
  1181.         mutex_lock(&fb_helper->dev->mode_config.mutex);
  1182.         if (!drm_fb_helper_is_bound(fb_helper)) {
  1183.                 fb_helper->delayed_hotplug = true;
  1184.                 mutex_unlock(&fb_helper->dev->mode_config.mutex);
  1185.                 return 0;
  1186.         }
  1187.         DRM_DEBUG_KMS("\n");
  1188.  
  1189.         max_width = fb_helper->fb->width;
  1190.         max_height = fb_helper->fb->height;
  1191.         bpp_sel = fb_helper->fb->bits_per_pixel;
  1192.  
  1193.         count = drm_fb_helper_probe_connector_modes(fb_helper, max_width,
  1194.                                                     max_height);
  1195.         mutex_unlock(&fb_helper->dev->mode_config.mutex);
  1196.  
  1197.         drm_modeset_lock_all(dev);
  1198.         drm_setup_crtcs(fb_helper);
  1199.         drm_modeset_unlock_all(dev);
  1200.         drm_fb_helper_set_par(fb_helper->fbdev);
  1201.  
  1202.         return 0;
  1203. }
  1204. EXPORT_SYMBOL(drm_fb_helper_hotplug_event);
  1205.  
  1206.  
  1207.  
  1208.