Subversion Repositories Kolibri OS

Rev

Rev 5271 | Go to most recent revision | Blame | Compare with Previous | Last modification | View Log | Download | RSS feed

  1. /*
  2.  * Copyright (C) 2014 Intel Corporation
  3.  *
  4.  * DRM universal plane helper functions
  5.  *
  6.  * Permission is hereby granted, free of charge, to any person obtaining a
  7.  * copy of this software and associated documentation files (the "Software"),
  8.  * to deal in the Software without restriction, including without limitation
  9.  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10.  * and/or sell copies of the Software, and to permit persons to whom the
  11.  * Software is furnished to do so, subject to the following conditions:
  12.  *
  13.  * The above copyright notice and this permission notice (including the next
  14.  * paragraph) shall be included in all copies or substantial portions of the
  15.  * Software.
  16.  *
  17.  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18.  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19.  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20.  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21.  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22.  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23.  * SOFTWARE.
  24.  */
  25.  
  26. #include <linux/list.h>
  27. #include <drm/drmP.h>
  28. #include <drm/drm_plane_helper.h>
  29. #include <drm/drm_rect.h>
  30. #include <drm/drm_atomic.h>
  31. #include <drm/drm_crtc_helper.h>
  32. #include <drm/drm_atomic_helper.h>
  33.  
  34. #define SUBPIXEL_MASK 0xffff
  35.  
  36. /**
  37.  * DOC: overview
  38.  *
  39.  * This helper library has two parts. The first part has support to implement
  40.  * primary plane support on top of the normal CRTC configuration interface.
  41.  * Since the legacy ->set_config interface ties the primary plane together with
  42.  * the CRTC state this does not allow userspace to disable the primary plane
  43.  * itself.  To avoid too much duplicated code use
  44.  * drm_plane_helper_check_update() which can be used to enforce the same
  45.  * restrictions as primary planes had thus. The default primary plane only
  46.  * expose XRBG8888 and ARGB8888 as valid pixel formats for the attached
  47.  * framebuffer.
  48.  *
  49.  * Drivers are highly recommended to implement proper support for primary
  50.  * planes, and newly merged drivers must not rely upon these transitional
  51.  * helpers.
  52.  *
  53.  * The second part also implements transitional helpers which allow drivers to
  54.  * gradually switch to the atomic helper infrastructure for plane updates. Once
  55.  * that switch is complete drivers shouldn't use these any longer, instead using
  56.  * the proper legacy implementations for update and disable plane hooks provided
  57.  * by the atomic helpers.
  58.  *
  59.  * Again drivers are strongly urged to switch to the new interfaces.
  60.  */
  61.  
  62. /*
  63.  * This is the minimal list of formats that seem to be safe for modeset use
  64.  * with all current DRM drivers.  Most hardware can actually support more
  65.  * formats than this and drivers may specify a more accurate list when
  66.  * creating the primary plane.  However drivers that still call
  67.  * drm_plane_init() will use this minimal format list as the default.
  68.  */
  69. static const uint32_t safe_modeset_formats[] = {
  70.         DRM_FORMAT_XRGB8888,
  71.         DRM_FORMAT_ARGB8888,
  72. };
  73.  
  74. /*
  75.  * Returns the connectors currently associated with a CRTC.  This function
  76.  * should be called twice:  once with a NULL connector list to retrieve
  77.  * the list size, and once with the properly allocated list to be filled in.
  78.  */
  79. static int get_connectors_for_crtc(struct drm_crtc *crtc,
  80.                                    struct drm_connector **connector_list,
  81.                                    int num_connectors)
  82. {
  83.         struct drm_device *dev = crtc->dev;
  84.         struct drm_connector *connector;
  85.         int count = 0;
  86.  
  87.         /*
  88.          * Note: Once we change the plane hooks to more fine-grained locking we
  89.          * need to grab the connection_mutex here to be able to make these
  90.          * checks.
  91.          */
  92.         WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
  93.  
  94.         drm_for_each_connector(connector, dev) {
  95.                 if (connector->encoder && connector->encoder->crtc == crtc) {
  96.                         if (connector_list != NULL && count < num_connectors)
  97.                                 *(connector_list++) = connector;
  98.  
  99.                         count++;
  100.                 }
  101.         }
  102.  
  103.         return count;
  104. }
  105.  
  106. /**
  107.  * drm_plane_helper_check_update() - Check plane update for validity
  108.  * @plane: plane object to update
  109.  * @crtc: owning CRTC of owning plane
  110.  * @fb: framebuffer to flip onto plane
  111.  * @src: source coordinates in 16.16 fixed point
  112.  * @dest: integer destination coordinates
  113.  * @clip: integer clipping coordinates
  114.  * @min_scale: minimum @src:@dest scaling factor in 16.16 fixed point
  115.  * @max_scale: maximum @src:@dest scaling factor in 16.16 fixed point
  116.  * @can_position: is it legal to position the plane such that it
  117.  *                doesn't cover the entire crtc?  This will generally
  118.  *                only be false for primary planes.
  119.  * @can_update_disabled: can the plane be updated while the crtc
  120.  *                       is disabled?
  121.  * @visible: output parameter indicating whether plane is still visible after
  122.  *           clipping
  123.  *
  124.  * Checks that a desired plane update is valid.  Drivers that provide
  125.  * their own plane handling rather than helper-provided implementations may
  126.  * still wish to call this function to avoid duplication of error checking
  127.  * code.
  128.  *
  129.  * RETURNS:
  130.  * Zero if update appears valid, error code on failure
  131.  */
  132. int drm_plane_helper_check_update(struct drm_plane *plane,
  133.                                     struct drm_crtc *crtc,
  134.                                     struct drm_framebuffer *fb,
  135.                                     struct drm_rect *src,
  136.                                     struct drm_rect *dest,
  137.                                     const struct drm_rect *clip,
  138.                                     int min_scale,
  139.                                     int max_scale,
  140.                                     bool can_position,
  141.                                     bool can_update_disabled,
  142.                                     bool *visible)
  143. {
  144.         int hscale, vscale;
  145.  
  146.         if (!fb) {
  147.                 *visible = false;
  148.                 return 0;
  149.         }
  150.  
  151.         /* crtc should only be NULL when disabling (i.e., !fb) */
  152.         if (WARN_ON(!crtc)) {
  153.                 *visible = false;
  154.                 return 0;
  155.         }
  156.  
  157.         if (!crtc->enabled && !can_update_disabled) {
  158.                 DRM_DEBUG_KMS("Cannot update plane of a disabled CRTC.\n");
  159.                 return -EINVAL;
  160.         }
  161.  
  162.         /* Check scaling */
  163.         hscale = drm_rect_calc_hscale(src, dest, min_scale, max_scale);
  164.         vscale = drm_rect_calc_vscale(src, dest, min_scale, max_scale);
  165.         if (hscale < 0 || vscale < 0) {
  166.                 DRM_DEBUG_KMS("Invalid scaling of plane\n");
  167.                 return -ERANGE;
  168.         }
  169.  
  170.         *visible = drm_rect_clip_scaled(src, dest, clip, hscale, vscale);
  171.         if (!*visible)
  172.                 /*
  173.                  * Plane isn't visible; some drivers can handle this
  174.                  * so we just return success here.  Drivers that can't
  175.                  * (including those that use the primary plane helper's
  176.                  * update function) will return an error from their
  177.                  * update_plane handler.
  178.                  */
  179.                 return 0;
  180.  
  181.         if (!can_position && !drm_rect_equals(dest, clip)) {
  182.                 DRM_DEBUG_KMS("Plane must cover entire CRTC\n");
  183.                 return -EINVAL;
  184.         }
  185.  
  186.         return 0;
  187. }
  188. EXPORT_SYMBOL(drm_plane_helper_check_update);
  189.  
  190. /**
  191.  * drm_primary_helper_update() - Helper for primary plane update
  192.  * @plane: plane object to update
  193.  * @crtc: owning CRTC of owning plane
  194.  * @fb: framebuffer to flip onto plane
  195.  * @crtc_x: x offset of primary plane on crtc
  196.  * @crtc_y: y offset of primary plane on crtc
  197.  * @crtc_w: width of primary plane rectangle on crtc
  198.  * @crtc_h: height of primary plane rectangle on crtc
  199.  * @src_x: x offset of @fb for panning
  200.  * @src_y: y offset of @fb for panning
  201.  * @src_w: width of source rectangle in @fb
  202.  * @src_h: height of source rectangle in @fb
  203.  *
  204.  * Provides a default plane update handler for primary planes.  This is handler
  205.  * is called in response to a userspace SetPlane operation on the plane with a
  206.  * non-NULL framebuffer.  We call the driver's modeset handler to update the
  207.  * framebuffer.
  208.  *
  209.  * SetPlane() on a primary plane of a disabled CRTC is not supported, and will
  210.  * return an error.
  211.  *
  212.  * Note that we make some assumptions about hardware limitations that may not be
  213.  * true for all hardware --
  214.  *   1) Primary plane cannot be repositioned.
  215.  *   2) Primary plane cannot be scaled.
  216.  *   3) Primary plane must cover the entire CRTC.
  217.  *   4) Subpixel positioning is not supported.
  218.  * Drivers for hardware that don't have these restrictions can provide their
  219.  * own implementation rather than using this helper.
  220.  *
  221.  * RETURNS:
  222.  * Zero on success, error code on failure
  223.  */
  224. int drm_primary_helper_update(struct drm_plane *plane, struct drm_crtc *crtc,
  225.                               struct drm_framebuffer *fb,
  226.                               int crtc_x, int crtc_y,
  227.                               unsigned int crtc_w, unsigned int crtc_h,
  228.                               uint32_t src_x, uint32_t src_y,
  229.                               uint32_t src_w, uint32_t src_h)
  230. {
  231.         struct drm_mode_set set = {
  232.                 .crtc = crtc,
  233.                 .fb = fb,
  234.                 .mode = &crtc->mode,
  235.                 .x = src_x >> 16,
  236.                 .y = src_y >> 16,
  237.         };
  238.         struct drm_rect src = {
  239.                 .x1 = src_x,
  240.                 .y1 = src_y,
  241.                 .x2 = src_x + src_w,
  242.                 .y2 = src_y + src_h,
  243.         };
  244.         struct drm_rect dest = {
  245.                 .x1 = crtc_x,
  246.                 .y1 = crtc_y,
  247.                 .x2 = crtc_x + crtc_w,
  248.                 .y2 = crtc_y + crtc_h,
  249.         };
  250.         const struct drm_rect clip = {
  251.                 .x2 = crtc->mode.hdisplay,
  252.                 .y2 = crtc->mode.vdisplay,
  253.         };
  254.         struct drm_connector **connector_list;
  255.         int num_connectors, ret;
  256.         bool visible;
  257.  
  258.         ret = drm_plane_helper_check_update(plane, crtc, fb,
  259.                                             &src, &dest, &clip,
  260.                                             DRM_PLANE_HELPER_NO_SCALING,
  261.                                             DRM_PLANE_HELPER_NO_SCALING,
  262.                                             false, false, &visible);
  263.         if (ret)
  264.                 return ret;
  265.  
  266.         if (!visible)
  267.                 /*
  268.                  * Primary plane isn't visible.  Note that unless a driver
  269.                  * provides their own disable function, this will just
  270.                  * wind up returning -EINVAL to userspace.
  271.                  */
  272.                 return plane->funcs->disable_plane(plane);
  273.  
  274.         /* Find current connectors for CRTC */
  275.         num_connectors = get_connectors_for_crtc(crtc, NULL, 0);
  276.         BUG_ON(num_connectors == 0);
  277.         connector_list = kzalloc(num_connectors * sizeof(*connector_list),
  278.                                  GFP_KERNEL);
  279.         if (!connector_list)
  280.                 return -ENOMEM;
  281.         get_connectors_for_crtc(crtc, connector_list, num_connectors);
  282.  
  283.         set.connectors = connector_list;
  284.         set.num_connectors = num_connectors;
  285.  
  286.         /*
  287.          * We call set_config() directly here rather than using
  288.          * drm_mode_set_config_internal.  We're reprogramming the same
  289.          * connectors that were already in use, so we shouldn't need the extra
  290.          * cross-CRTC fb refcounting to accomodate stealing connectors.
  291.          * drm_mode_setplane() already handles the basic refcounting for the
  292.          * framebuffers involved in this operation.
  293.          */
  294.         ret = crtc->funcs->set_config(&set);
  295.  
  296.         kfree(connector_list);
  297.         return ret;
  298. }
  299. EXPORT_SYMBOL(drm_primary_helper_update);
  300.  
  301. /**
  302.  * drm_primary_helper_disable() - Helper for primary plane disable
  303.  * @plane: plane to disable
  304.  *
  305.  * Provides a default plane disable handler for primary planes.  This is handler
  306.  * is called in response to a userspace SetPlane operation on the plane with a
  307.  * NULL framebuffer parameter.  It unconditionally fails the disable call with
  308.  * -EINVAL the only way to disable the primary plane without driver support is
  309.  * to disable the entier CRTC. Which does not match the plane ->disable hook.
  310.  *
  311.  * Note that some hardware may be able to disable the primary plane without
  312.  * disabling the whole CRTC.  Drivers for such hardware should provide their
  313.  * own disable handler that disables just the primary plane (and they'll likely
  314.  * need to provide their own update handler as well to properly re-enable a
  315.  * disabled primary plane).
  316.  *
  317.  * RETURNS:
  318.  * Unconditionally returns -EINVAL.
  319.  */
  320. int drm_primary_helper_disable(struct drm_plane *plane)
  321. {
  322.         return -EINVAL;
  323. }
  324. EXPORT_SYMBOL(drm_primary_helper_disable);
  325.  
  326. /**
  327.  * drm_primary_helper_destroy() - Helper for primary plane destruction
  328.  * @plane: plane to destroy
  329.  *
  330.  * Provides a default plane destroy handler for primary planes.  This handler
  331.  * is called during CRTC destruction.  We disable the primary plane, remove
  332.  * it from the DRM plane list, and deallocate the plane structure.
  333.  */
  334. void drm_primary_helper_destroy(struct drm_plane *plane)
  335. {
  336.         drm_plane_cleanup(plane);
  337.         kfree(plane);
  338. }
  339. EXPORT_SYMBOL(drm_primary_helper_destroy);
  340.  
  341. const struct drm_plane_funcs drm_primary_helper_funcs = {
  342.         .update_plane = drm_primary_helper_update,
  343.         .disable_plane = drm_primary_helper_disable,
  344.         .destroy = drm_primary_helper_destroy,
  345. };
  346. EXPORT_SYMBOL(drm_primary_helper_funcs);
  347.  
  348. static struct drm_plane *create_primary_plane(struct drm_device *dev)
  349. {
  350.         struct drm_plane *primary;
  351.         int ret;
  352.  
  353.         primary = kzalloc(sizeof(*primary), GFP_KERNEL);
  354.         if (primary == NULL) {
  355.                 DRM_DEBUG_KMS("Failed to allocate primary plane\n");
  356.                 return NULL;
  357.         }
  358.  
  359.         /*
  360.          * Remove the format_default field from drm_plane when dropping
  361.          * this helper.
  362.          */
  363.         primary->format_default = true;
  364.  
  365.         /* possible_crtc's will be filled in later by crtc_init */
  366.         ret = drm_universal_plane_init(dev, primary, 0,
  367.                                        &drm_primary_helper_funcs,
  368.                                        safe_modeset_formats,
  369.                                        ARRAY_SIZE(safe_modeset_formats),
  370.                                        DRM_PLANE_TYPE_PRIMARY);
  371.         if (ret) {
  372.                 kfree(primary);
  373.                 primary = NULL;
  374.         }
  375.  
  376.         return primary;
  377. }
  378.  
  379. /**
  380.  * drm_crtc_init - Legacy CRTC initialization function
  381.  * @dev: DRM device
  382.  * @crtc: CRTC object to init
  383.  * @funcs: callbacks for the new CRTC
  384.  *
  385.  * Initialize a CRTC object with a default helper-provided primary plane and no
  386.  * cursor plane.
  387.  *
  388.  * Returns:
  389.  * Zero on success, error code on failure.
  390.  */
  391. int drm_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
  392.                   const struct drm_crtc_funcs *funcs)
  393. {
  394.         struct drm_plane *primary;
  395.  
  396.         primary = create_primary_plane(dev);
  397.         return drm_crtc_init_with_planes(dev, crtc, primary, NULL, funcs);
  398. }
  399. EXPORT_SYMBOL(drm_crtc_init);
  400.  
  401. int drm_plane_helper_commit(struct drm_plane *plane,
  402.                             struct drm_plane_state *plane_state,
  403.                             struct drm_framebuffer *old_fb)
  404. {
  405.         const struct drm_plane_helper_funcs *plane_funcs;
  406.         struct drm_crtc *crtc[2];
  407.         const struct drm_crtc_helper_funcs *crtc_funcs[2];
  408.         int i, ret = 0;
  409.  
  410.         plane_funcs = plane->helper_private;
  411.  
  412.         /* Since this is a transitional helper we can't assume that plane->state
  413.          * is always valid. Hence we need to use plane->crtc instead of
  414.          * plane->state->crtc as the old crtc. */
  415.         crtc[0] = plane->crtc;
  416.         crtc[1] = crtc[0] != plane_state->crtc ? plane_state->crtc : NULL;
  417.  
  418.         for (i = 0; i < 2; i++)
  419.                 crtc_funcs[i] = crtc[i] ? crtc[i]->helper_private : NULL;
  420.  
  421.         if (plane_funcs->atomic_check) {
  422.                 ret = plane_funcs->atomic_check(plane, plane_state);
  423.                 if (ret)
  424.                         goto out;
  425.         }
  426.  
  427.         if (plane_funcs->prepare_fb && plane_state->fb &&
  428.             plane_state->fb != old_fb) {
  429.                 ret = plane_funcs->prepare_fb(plane,
  430.                                               plane_state);
  431.                 if (ret)
  432.                         goto out;
  433.         }
  434.  
  435.         /* Point of no return, commit sw state. */
  436.         swap(plane->state, plane_state);
  437.  
  438.         for (i = 0; i < 2; i++) {
  439.                 if (crtc_funcs[i] && crtc_funcs[i]->atomic_begin)
  440.                         crtc_funcs[i]->atomic_begin(crtc[i], crtc[i]->state);
  441.         }
  442.  
  443.         /*
  444.          * Drivers may optionally implement the ->atomic_disable callback, so
  445.          * special-case that here.
  446.          */
  447.         if (drm_atomic_plane_disabling(plane, plane_state) &&
  448.             plane_funcs->atomic_disable)
  449.                 plane_funcs->atomic_disable(plane, plane_state);
  450.         else
  451.                 plane_funcs->atomic_update(plane, plane_state);
  452.  
  453.         for (i = 0; i < 2; i++) {
  454.                 if (crtc_funcs[i] && crtc_funcs[i]->atomic_flush)
  455.                         crtc_funcs[i]->atomic_flush(crtc[i], crtc[i]->state);
  456.         }
  457.  
  458.         /*
  459.          * If we only moved the plane and didn't change fb's, there's no need to
  460.          * wait for vblank.
  461.          */
  462.         if (plane->state->fb == old_fb)
  463.                 goto out;
  464.  
  465.         for (i = 0; i < 2; i++) {
  466.                 if (!crtc[i])
  467.                         continue;
  468.  
  469.                 if (crtc[i]->cursor == plane)
  470.                         continue;
  471.  
  472.                 /* There's no other way to figure out whether the crtc is running. */
  473.                 ret = drm_crtc_vblank_get(crtc[i]);
  474.                 if (ret == 0) {
  475.                         drm_crtc_wait_one_vblank(crtc[i]);
  476.                         drm_crtc_vblank_put(crtc[i]);
  477.                 }
  478.  
  479.                 ret = 0;
  480.         }
  481.  
  482.         if (plane_funcs->cleanup_fb)
  483.                 plane_funcs->cleanup_fb(plane, plane_state);
  484. out:
  485.         if (plane_state) {
  486.                 if (plane->funcs->atomic_destroy_state)
  487.                         plane->funcs->atomic_destroy_state(plane, plane_state);
  488.                 else
  489.                         drm_atomic_helper_plane_destroy_state(plane, plane_state);
  490.         }
  491.  
  492.         return ret;
  493. }
  494.  
  495. /**
  496.  * drm_plane_helper_update() - Transitional helper for plane update
  497.  * @plane: plane object to update
  498.  * @crtc: owning CRTC of owning plane
  499.  * @fb: framebuffer to flip onto plane
  500.  * @crtc_x: x offset of primary plane on crtc
  501.  * @crtc_y: y offset of primary plane on crtc
  502.  * @crtc_w: width of primary plane rectangle on crtc
  503.  * @crtc_h: height of primary plane rectangle on crtc
  504.  * @src_x: x offset of @fb for panning
  505.  * @src_y: y offset of @fb for panning
  506.  * @src_w: width of source rectangle in @fb
  507.  * @src_h: height of source rectangle in @fb
  508.  *
  509.  * Provides a default plane update handler using the atomic plane update
  510.  * functions. It is fully left to the driver to check plane constraints and
  511.  * handle corner-cases like a fully occluded or otherwise invisible plane.
  512.  *
  513.  * This is useful for piecewise transitioning of a driver to the atomic helpers.
  514.  *
  515.  * RETURNS:
  516.  * Zero on success, error code on failure
  517.  */
  518. int drm_plane_helper_update(struct drm_plane *plane, struct drm_crtc *crtc,
  519.                             struct drm_framebuffer *fb,
  520.                             int crtc_x, int crtc_y,
  521.                             unsigned int crtc_w, unsigned int crtc_h,
  522.                             uint32_t src_x, uint32_t src_y,
  523.                             uint32_t src_w, uint32_t src_h)
  524. {
  525.         struct drm_plane_state *plane_state;
  526.  
  527.         if (plane->funcs->atomic_duplicate_state)
  528.                 plane_state = plane->funcs->atomic_duplicate_state(plane);
  529.         else {
  530.                 if (!plane->state)
  531.                         drm_atomic_helper_plane_reset(plane);
  532.  
  533.                 plane_state = drm_atomic_helper_plane_duplicate_state(plane);
  534.         }
  535.         if (!plane_state)
  536.                 return -ENOMEM;
  537.         plane_state->plane = plane;
  538.  
  539.         plane_state->crtc = crtc;
  540.         drm_atomic_set_fb_for_plane(plane_state, fb);
  541.         plane_state->crtc_x = crtc_x;
  542.         plane_state->crtc_y = crtc_y;
  543.         plane_state->crtc_h = crtc_h;
  544.         plane_state->crtc_w = crtc_w;
  545.         plane_state->src_x = src_x;
  546.         plane_state->src_y = src_y;
  547.         plane_state->src_h = src_h;
  548.         plane_state->src_w = src_w;
  549.  
  550.         return drm_plane_helper_commit(plane, plane_state, plane->fb);
  551. }
  552. EXPORT_SYMBOL(drm_plane_helper_update);
  553.  
  554. /**
  555.  * drm_plane_helper_disable() - Transitional helper for plane disable
  556.  * @plane: plane to disable
  557.  *
  558.  * Provides a default plane disable handler using the atomic plane update
  559.  * functions. It is fully left to the driver to check plane constraints and
  560.  * handle corner-cases like a fully occluded or otherwise invisible plane.
  561.  *
  562.  * This is useful for piecewise transitioning of a driver to the atomic helpers.
  563.  *
  564.  * RETURNS:
  565.  * Zero on success, error code on failure
  566.  */
  567. int drm_plane_helper_disable(struct drm_plane *plane)
  568. {
  569.         struct drm_plane_state *plane_state;
  570.  
  571.         /* crtc helpers love to call disable functions for already disabled hw
  572.          * functions. So cope with that. */
  573.         if (!plane->crtc)
  574.                 return 0;
  575.  
  576.         if (plane->funcs->atomic_duplicate_state)
  577.                 plane_state = plane->funcs->atomic_duplicate_state(plane);
  578.         else {
  579.                 if (!plane->state)
  580.                         drm_atomic_helper_plane_reset(plane);
  581.  
  582.                 plane_state = drm_atomic_helper_plane_duplicate_state(plane);
  583.         }
  584.         if (!plane_state)
  585.                 return -ENOMEM;
  586.         plane_state->plane = plane;
  587.  
  588.         plane_state->crtc = NULL;
  589.         drm_atomic_set_fb_for_plane(plane_state, NULL);
  590.  
  591.         return drm_plane_helper_commit(plane, plane_state, plane->fb);
  592. }
  593. EXPORT_SYMBOL(drm_plane_helper_disable);
  594.