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Diffstat (limited to 'drivers/gpu/drm/drm_damage_helper.c')
-rw-r--r-- | drivers/gpu/drm/drm_damage_helper.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_damage_helper.c b/drivers/gpu/drm/drm_damage_helper.c new file mode 100644 index 000000000000..8dc906a489a9 --- /dev/null +++ b/drivers/gpu/drm/drm_damage_helper.c @@ -0,0 +1,83 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT +/************************************************************************** + * + * Copyright (c) 2018 VMware, Inc., Palo Alto, CA., USA + * All Rights Reserved. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sub license, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice (including the + * next paragraph) shall be included in all copies or substantial portions + * of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL + * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, + * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR + * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE + * USE OR OTHER DEALINGS IN THE SOFTWARE. + * + * Authors: + * Deepak Rawat <drawat@vmware.com> + * + **************************************************************************/ + +#include <drm/drm_damage_helper.h> + +/** + * DOC: overview + * + * FB_DAMAGE_CLIPS is an optional plane property which provides a means to + * specify a list of damage rectangles on a plane in framebuffer coordinates of + * the framebuffer attached to the plane. In current context damage is the area + * of plane framebuffer that has changed since last plane update (also called + * page-flip), irrespective of whether currently attached framebuffer is same as + * framebuffer attached during last plane update or not. + * + * FB_DAMAGE_CLIPS is a hint to kernel which could be helpful for some drivers + * to optimize internally especially for virtual devices where each framebuffer + * change needs to be transmitted over network, usb, etc. + * + * Since FB_DAMAGE_CLIPS is a hint so it is an optional property. User-space can + * ignore damage clips property and in that case driver will do a full plane + * update. In case damage clips are provided then it is guaranteed that the area + * inside damage clips will be updated to plane. For efficiency driver can do + * full update or can update more than specified in damage clips. Since driver + * is free to read more, user-space must always render the entire visible + * framebuffer. Otherwise there can be corruptions. Also, if a user-space + * provides damage clips which doesn't encompass the actual damage to + * framebuffer (since last plane update) can result in incorrect rendering. + * + * FB_DAMAGE_CLIPS is a blob property with the layout of blob data is simply an + * array of &drm_mode_rect. Unlike plane &drm_plane_state.src coordinates, + * damage clips are not in 16.16 fixed point. Similar to plane src in + * framebuffer, damage clips cannot be negative. In damage clip, x1/y1 are + * inclusive and x2/y2 are exclusive. While kernel does not error for overlapped + * damage clips, it is strongly discouraged. + * + * Drivers that are interested in damage interface for plane should enable + * FB_DAMAGE_CLIPS property by calling drm_plane_enable_fb_damage_clips(). + */ + +/** + * drm_plane_enable_fb_damage_clips - Enables plane fb damage clips property. + * @plane: Plane on which to enable damage clips property. + * + * This function lets driver to enable the damage clips property on a plane. + */ +void drm_plane_enable_fb_damage_clips(struct drm_plane *plane) +{ + struct drm_device *dev = plane->dev; + struct drm_mode_config *config = &dev->mode_config; + + drm_object_attach_property(&plane->base, config->prop_fb_damage_clips, + 0); +} +EXPORT_SYMBOL(drm_plane_enable_fb_damage_clips); |