drivers/gpu/drm/evdi/evdi_painter.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2013 - 2018 DisplayLink (UK) Ltd.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License v2. See the file COPYING in the main directory of this archive for
 * more details.
 */

#include "linux/thread_info.h"
#include "linux/mm.h"
#include <drm/drmP.h>
#include <drm/drm_edid.h>
#include <uapi/drm/evdi_drm.h>
#include "evdi_drv.h"
#include "evdi_cursor.h"
#include <linux/mutex.h>
#include <linux/compiler.h>

struct evdi_event_cursor_set_pending {
	struct drm_pending_event base;
	struct drm_evdi_event_cursor_set cursor_set;
};

struct evdi_event_cursor_move_pending {
	struct drm_pending_event base;
	struct drm_evdi_event_cursor_move cursor_move;
};

struct evdi_event_update_ready_pending {
	struct drm_pending_event base;
	struct drm_evdi_event_update_ready update_ready;
};

struct evdi_event_dpms_pending {
	struct drm_pending_event base;
	struct drm_evdi_event_dpms dpms;
};

struct evdi_event_mode_changed_pending {
	struct drm_pending_event base;
	struct drm_evdi_event_mode_changed mode_changed;
};

struct evdi_event_crtc_state_pending {
	struct drm_pending_event base;
	struct drm_evdi_event_crtc_state crtc_state;
};

#define MAX_DIRTS 16
#define EDID_EXT_BLOCK_SIZE 128
#define MAX_EDID_SIZE (255 * EDID_EXT_BLOCK_SIZE + sizeof(struct edid))

struct evdi_painter {
	bool is_connected;
	struct edid *edid;
	unsigned int edid_length;

	struct mutex lock;
	struct mutex new_scanout_fb_lock;
	struct drm_clip_rect dirty_rects[MAX_DIRTS];
	int num_dirts;
	struct evdi_framebuffer *new_scanout_fb;
	struct evdi_framebuffer *scanout_fb;

	struct drm_file *drm_filp;

	bool was_update_requested;
	bool needs_full_modeset;
};

static void expand_rect(struct drm_clip_rect *a, const struct drm_clip_rect *b)
{
	a->x1 = min(a->x1, b->x1);
	a->y1 = min(a->y1, b->y1);
	a->x2 = max(a->x2, b->x2);
	a->y2 = max(a->y2, b->y2);
}

static int rect_area(const struct drm_clip_rect *r)
{
	return (r->x2 - r->x1) * (r->y2 - r->y1);
}

static void merge_dirty_rects(struct drm_clip_rect *rects, int *count)
{
	int a, b;

	for (a = 0; a < *count - 1; ++a) {
		for (b = a + 1; b < *count;) {
			/* collapse to bounding rect if it is fewer pixels */
			const int area_a = rect_area(&rects[a]);
			const int area_b = rect_area(&rects[b]);
			struct drm_clip_rect bounding_rect = rects[a];

			expand_rect(&bounding_rect, &rects[b]);

			if (rect_area(&bounding_rect) <= area_a + area_b) {
				rects[a] = bounding_rect;
				rects[b] = rects[*count - 1];
				/* repass */
				b = a + 1;
				--*count;
			} else {
				++b;
			}
		}
	}
}

static void collapse_dirty_rects(struct drm_clip_rect *rects, int *count)
{
	int i;

	EVDI_CHECKPT();
	EVDI_WARN("Not enough space for clip rects! Rects will be collapsed");

	for (i = 1; i < *count; ++i)
		expand_rect(&rects[0], &rects[i]);

	*count = 1;
}

static int copy_primary_pixels(struct evdi_framebuffer *ufb,
			       char __user *buffer,
			       int buf_byte_stride,
			       int num_rects, struct drm_clip_rect *rects,
			       int const max_x,
			       int const max_y)
{
	struct drm_framebuffer *fb = &ufb->base;
	struct drm_clip_rect *r;

	EVDI_CHECKPT();

	for (r = rects; r != rects + num_rects; ++r) {
		const int byte_offset = r->x1 * 4;
		const int byte_span = (r->x2 - r->x1) * 4;
		const int src_offset = fb->pitches[0] * r->y1 + byte_offset;
		const char *src = (char *)ufb->obj->vmapping + src_offset;
		const int dst_offset = buf_byte_stride * r->y1 + byte_offset;
		char __user *dst = buffer + dst_offset;
		int y = r->y2 - r->y1;

		/* rect size may correspond to previous resolution */
		if (max_x < r->x2 || max_y < r->y2) {
			EVDI_WARN("Rect size beyond expected dimensions\n");
			return -EFAULT;
		}

		EVDI_VERBOSE("copy rect %d,%d-%d,%d\n", r->x1, r->y1, r->x2,
			     r->y2);

		for (; y > 0; --y) {
			if (copy_to_user(dst, src, byte_span))
				return -EFAULT;

			src += fb->pitches[0];
			dst += buf_byte_stride;
		}
	}

	return 0;
}

static void copy_cursor_pixels(struct evdi_framebuffer *efb,
			      char __user *buffer,
			      int buf_byte_stride,
			      struct evdi_cursor *cursor)
{
	if (evdi_enable_cursor_blending) {
		evdi_cursor_lock(cursor);
		if (evdi_cursor_compose_and_copy(cursor,
						   efb,
						   buffer,
						   buf_byte_stride))
			EVDI_ERROR("Failed to blend cursor\n");

		evdi_cursor_unlock(cursor);
	}
}

#define painter_lock(painter)                           \
	do {                                            \
		EVDI_VERBOSE("Painter lock\n");         \
		mutex_lock(&painter->lock);             \
	} while (0)

#define painter_unlock(painter)                         \
	do {                                            \
		EVDI_VERBOSE("Painter unlock\n");       \
		mutex_unlock(&painter->lock);           \
	} while (0)

bool evdi_painter_is_connected(struct evdi_device *evdi)
{
	if (evdi && evdi->painter)
		return evdi->painter->is_connected;
	return false;
}

u8 *evdi_painter_get_edid_copy(struct evdi_device *evdi)
{
	u8 *block = NULL;

	EVDI_CHECKPT();

	painter_lock(evdi->painter);
	if (evdi_painter_is_connected(evdi) &&
		evdi->painter->edid &&
		evdi->painter->edid_length) {
		block = kmalloc(evdi->painter->edid_length, GFP_KERNEL);
		if (block) {
			memcpy(block,
			       evdi->painter->edid,
			       evdi->painter->edid_length);
			EVDI_DEBUG("(dev=%d) EDID valid\n", evdi->dev_index);
		}
	}
	painter_unlock(evdi->painter);
	return block;
}

static void evdi_painter_send_event(struct drm_file *drm_filp,
				    struct list_head *event_link)
{
	list_add_tail(event_link, &drm_filp->event_list);
	wake_up_interruptible(&drm_filp->event_wait);
}

static void evdi_painter_send_update_ready(struct evdi_painter *painter)
{
	struct evdi_event_update_ready_pending *event;

	if (painter->drm_filp) {
		event = kzalloc(sizeof(*event), GFP_KERNEL);
		event->update_ready.base.type = DRM_EVDI_EVENT_UPDATE_READY;
		event->update_ready.base.length = sizeof(event->update_ready);
		event->base.event = &event->update_ready.base;
		event->base.file_priv = painter->drm_filp;
		evdi_painter_send_event(painter->drm_filp, &event->base.link);
	} else {
		EVDI_WARN("Painter is not connected!");
	}
}

static uint32_t evdi_painter_get_gem_handle(struct evdi_painter *painter,
					   struct evdi_gem_object *obj)
{
	uint32_t handle = 0;

	if (!obj)
		return 0;

	handle = evdi_gem_object_handle_lookup(painter->drm_filp, &obj->base);

	if (handle)
		return handle;

	if (drm_gem_handle_create(painter->drm_filp,
			      &obj->base, &handle)) {
		EVDI_ERROR("Failed to create gem handle for %p\n",
			painter->drm_filp);
	}

	return handle;
}

void evdi_painter_send_cursor_set(struct evdi_painter *painter,
				  struct evdi_cursor *cursor)
{
	struct evdi_event_cursor_set_pending *event;
	struct evdi_gem_object *eobj = NULL;

	if (painter->drm_filp) {
		event = kzalloc(sizeof(*event), GFP_KERNEL);
		event->cursor_set.base.type = DRM_EVDI_EVENT_CURSOR_SET;
		event->cursor_set.base.length =
			sizeof(event->cursor_set);

		evdi_cursor_lock(cursor);
		event->cursor_set.enabled = evdi_cursor_enabled(cursor);
		evdi_cursor_hotpoint(cursor,
			&event->cursor_set.hot_x,
			&event->cursor_set.hot_y);
		evdi_cursor_size(cursor,
			&event->cursor_set.width,
			&event->cursor_set.height);
		evdi_cursor_format(cursor,
			&event->cursor_set.pixel_format);
		evdi_cursor_stride(cursor,
			&event->cursor_set.stride);
		eobj = evdi_cursor_gem(cursor);
		event->cursor_set.buffer_handle =
			evdi_painter_get_gem_handle(painter, eobj);
		if (eobj)
			event->cursor_set.buffer_length = eobj->base.size;
		if (!event->cursor_set.buffer_handle) {
			event->cursor_set.enabled = false;
			event->cursor_set.buffer_length = 0;
		}
		evdi_cursor_unlock(cursor);

		event->base.event = &event->cursor_set.base;
		event->base.file_priv = painter->drm_filp;
		evdi_painter_send_event(painter->drm_filp, &event->base.link);
	} else {
		EVDI_WARN("Painter is not connected!");
	}
}

void evdi_painter_send_cursor_move(struct evdi_painter *painter,
				   struct evdi_cursor *cursor)
{
	struct evdi_event_cursor_move_pending *event;

	if (painter->drm_filp) {
		event = kzalloc(sizeof(*event), GFP_KERNEL);
		event->cursor_move.base.type = DRM_EVDI_EVENT_CURSOR_MOVE;
		event->cursor_move.base.length = sizeof(event->cursor_move);

		evdi_cursor_lock(cursor);
		evdi_cursor_position(
			cursor,
			&event->cursor_move.x,
			&event->cursor_move.y);
		evdi_cursor_unlock(cursor);

		event->base.event = &event->cursor_move.base;
		event->base.file_priv = painter->drm_filp;
		evdi_painter_send_event(painter->drm_filp, &event->base.link);
	} else {
		EVDI_WARN("Painter is not connected!");
	}
}

static void evdi_painter_send_dpms(struct evdi_painter *painter, int mode)
{
	struct evdi_event_dpms_pending *event;

	if (painter->drm_filp) {
		event = kzalloc(sizeof(*event), GFP_KERNEL);
		event->dpms.base.type = DRM_EVDI_EVENT_DPMS;
		event->dpms.base.length = sizeof(event->dpms);
		event->dpms.mode = mode;
		event->base.event = &event->dpms.base;
		event->base.file_priv = painter->drm_filp;
		evdi_painter_send_event(painter->drm_filp, &event->base.link);
	} else {
		EVDI_WARN("Painter is not connected!");
	}
}

static void evdi_painter_send_crtc_state(struct evdi_painter *painter,
					 int state)
{
	struct evdi_event_crtc_state_pending *event;

	if (painter->drm_filp) {
		event = kzalloc(sizeof(*event), GFP_KERNEL);
		event->crtc_state.base.type = DRM_EVDI_EVENT_CRTC_STATE;
		event->crtc_state.base.length = sizeof(event->crtc_state);
		event->crtc_state.state = state;
		event->base.event = &event->crtc_state.base;
		event->base.file_priv = painter->drm_filp;
		evdi_painter_send_event(painter->drm_filp, &event->base.link);
	} else {
		EVDI_WARN("Painter is not connected!");
	}
}

static void evdi_painter_send_mode_changed(
	struct evdi_painter *painter,
	struct drm_display_mode *current_mode,
	int32_t bits_per_pixel,
	uint32_t pixel_format)
{
	struct evdi_event_mode_changed_pending *event;

	if (painter->drm_filp) {
		event = kzalloc(sizeof(*event), GFP_KERNEL);
		event->mode_changed.base.type = DRM_EVDI_EVENT_MODE_CHANGED;
		event->mode_changed.base.length = sizeof(event->mode_changed);

		event->mode_changed.hdisplay = current_mode->hdisplay;
		event->mode_changed.vdisplay = current_mode->vdisplay;
		event->mode_changed.vrefresh =
			drm_mode_vrefresh(current_mode);
		event->mode_changed.bits_per_pixel = bits_per_pixel;
		event->mode_changed.pixel_format = pixel_format;

		event->base.event = &event->mode_changed.base;
		event->base.file_priv = painter->drm_filp;
		evdi_painter_send_event(painter->drm_filp, &event->base.link);
	} else {
		EVDI_WARN("Painter is not connected!");
	}
}

void evdi_painter_mark_dirty(struct evdi_device *evdi,
			     const struct drm_clip_rect *dirty_rect)
{
	struct drm_clip_rect rect;
	struct evdi_framebuffer *efb = NULL;
	struct evdi_painter *painter = evdi->painter;

	painter_lock(evdi->painter);
	efb = evdi->painter->scanout_fb;
	if (!efb) {
		EVDI_WARN("(dev=%d) Skip clip rect. Scanout buffer not set.\n",
			  evdi->dev_index);
		goto unlock;
	}

	rect = evdi_framebuffer_sanitize_rect(efb, dirty_rect);

	EVDI_VERBOSE("(dev=%d) %d,%d-%d,%d\n", evdi->dev_index, rect.x1,
		     rect.y1, rect.x2, rect.y2);

	if (painter->num_dirts == MAX_DIRTS)
		merge_dirty_rects(&painter->dirty_rects[0],
				  &painter->num_dirts);

	if (painter->num_dirts == MAX_DIRTS)
		collapse_dirty_rects(&painter->dirty_rects[0],
				     &painter->num_dirts);

	memcpy(&painter->dirty_rects[painter->num_dirts], &rect, sizeof(rect));
	painter->num_dirts++;

unlock:
	painter_unlock(evdi->painter);
}

void evdi_painter_send_update_ready_if_needed(struct evdi_device *evdi)
{
	struct evdi_painter *painter = evdi->painter;

	painter_lock(evdi->painter);
	if (painter->was_update_requested) {
		evdi_painter_send_update_ready(painter);
		painter->was_update_requested = false;
	}
	painter_unlock(evdi->painter);
}

void evdi_painter_dpms_notify(struct evdi_device *evdi, int mode)
{
	struct evdi_painter *painter = evdi->painter;

	if (painter) {
		EVDI_DEBUG("(dev=%d) Notifying dpms mode: %d\n",
			   evdi->dev_index, mode);
		evdi_painter_send_dpms(painter, mode);
	} else {
		EVDI_WARN("Painter does not exist!");
	}
}

void evdi_painter_crtc_state_notify(struct evdi_device *evdi, int state)
{
	struct evdi_painter *painter = evdi->painter;

	if (painter) {
		EVDI_DEBUG("(dev=%d) Notifying crtc state: %d\n",
			   evdi->dev_index, state);
		evdi_painter_send_crtc_state(painter, state);
	} else {
		EVDI_WARN("Painter does not exist!");
	}
}

void evdi_painter_mode_changed_notify(struct evdi_device *evdi,
				      struct drm_display_mode *new_mode)
{
	struct evdi_painter *painter = evdi->painter;
	struct drm_framebuffer *fb = &painter->scanout_fb->base;
	int bits_per_pixel;
	uint32_t pixel_format;

	if (fb == NULL)
		return;

	bits_per_pixel = fb->format->cpp[0];
	pixel_format = fb->format->format;

	EVDI_DEBUG("(dev=%d) Notifying mode changed: %dx%d@%d; bpp %d; ",
		   evdi->dev_index, new_mode->hdisplay, new_mode->vdisplay,
		   drm_mode_vrefresh(new_mode), bits_per_pixel);
	EVDI_DEBUG("pixel format %d\n", pixel_format);

	evdi_painter_send_mode_changed(painter,
				       new_mode,
				       bits_per_pixel,
				       pixel_format);
	if (painter)
		painter->needs_full_modeset = false;
}

static int
evdi_painter_connect(struct evdi_device *evdi,
		     void const __user *edid_data, unsigned int edid_length,
		     uint32_t sku_area_limit,
		     struct drm_file *file, int dev_index)
{
	struct evdi_painter *painter = evdi->painter;
	struct edid *new_edid = NULL;
	int expected_edid_size = 0;

	EVDI_DEBUG("(dev=%d) Process is trying to connect\n",
		   evdi->dev_index);
	evdi_log_process();

	if (edid_length < sizeof(struct edid)) {
		EVDI_ERROR("Edid length too small\n");
		return -EINVAL;
	}

	if (edid_length > MAX_EDID_SIZE) {
		EVDI_ERROR("Edid length too large\n");
		return -EINVAL;
	}

	new_edid = kzalloc(edid_length, GFP_KERNEL);
	if (!new_edid)
		return -ENOMEM;

	if (copy_from_user(new_edid, edid_data, edid_length)) {
		EVDI_ERROR("(dev=%d) Failed to read edid\n", dev_index);
		kfree(new_edid);
		return -EFAULT;
	}

	expected_edid_size = sizeof(struct edid) +
			     new_edid->extensions * EDID_EXT_BLOCK_SIZE;
	if (expected_edid_size != edid_length) {
		EVDI_ERROR("Wrong edid size. Expected %d but is %d\n",
			   expected_edid_size, edid_length);
		kfree(new_edid);
		return -EINVAL;
	}

	if (painter->drm_filp)
		EVDI_WARN("(dev=%d) Double connect - replacing %p with %p\n",
			  dev_index, painter->drm_filp, file);

	painter_lock(painter);

	evdi->dev_index = dev_index;
	evdi->sku_area_limit = sku_area_limit;
	painter->drm_filp = file;
	kfree(painter->edid);
	painter->edid_length = edid_length;
	painter->edid = new_edid;
	painter->is_connected = true;
	painter->needs_full_modeset = true;

	painter_unlock(painter);

	EVDI_DEBUG("(dev=%d) Connected with %p\n", evdi->dev_index,
		   painter->drm_filp);

	drm_helper_hpd_irq_event(evdi->ddev);


	return 0;
}

static int evdi_painter_disconnect(struct evdi_device *evdi,
	struct drm_file *file)
{
	struct evdi_painter *painter = evdi->painter;

	EVDI_CHECKPT();

	painter_lock(painter);

	if (file != painter->drm_filp) {
		painter_unlock(painter);
		return -EFAULT;
	}

	evdi_painter_set_new_scanout_buffer(evdi, NULL);

	if (painter->scanout_fb) {
		drm_framebuffer_unreference(&painter->scanout_fb->base);
		painter->scanout_fb = NULL;
	}

	painter->is_connected = false;

	EVDI_DEBUG("(dev=%d) Disconnected from %p\n", evdi->dev_index,
		   painter->drm_filp);

	evdi_cursor_enable(evdi->cursor, false);

	painter->drm_filp = NULL;

	painter->was_update_requested = false;

	painter_unlock(painter);

	drm_helper_hpd_irq_event(evdi->ddev);
	return 0;
}

void evdi_painter_close(struct evdi_device *evdi, struct drm_file *file)
{
	EVDI_CHECKPT();

	if (evdi->painter)
		evdi_painter_disconnect(evdi, file);
	else
		EVDI_WARN("Painter does not exist!");
}

int evdi_painter_connect_ioctl(struct drm_device *drm_dev, void *data,
			       struct drm_file *file)
{
	struct evdi_device *evdi = drm_dev->dev_private;
	struct evdi_painter *painter = evdi->painter;
	struct drm_evdi_connect *cmd = data;
	int ret;

	EVDI_CHECKPT();
	if (painter) {
		if (cmd->connected)
			ret = evdi_painter_connect(evdi,
					     cmd->edid,
					     cmd->edid_length,
					     cmd->sku_area_limit,
					     file,
					     cmd->dev_index);
		else
			ret = evdi_painter_disconnect(evdi, file);

		if (ret) {
			EVDI_WARN("(dev=%d) (pid=%d) disconnect failed\n",
				  evdi->dev_index, (int)task_pid_nr(current));
		}
		return ret;
	}
	EVDI_WARN("Painter does not exist!");
	return -ENODEV;
}

int evdi_painter_grabpix_ioctl(struct drm_device *drm_dev, void *data,
			       __always_unused struct drm_file *file)
{
	struct evdi_device *evdi = drm_dev->dev_private;
	struct evdi_painter *painter = evdi->painter;
	struct drm_evdi_grabpix *cmd = data;
	struct drm_framebuffer *fb = NULL;
	struct evdi_framebuffer *efb = NULL;
	int err = 0;

	EVDI_CHECKPT();

	if (!painter)
		return -ENODEV;

	painter_lock(painter);

	efb = painter->scanout_fb;

	if (!efb) {
		EVDI_ERROR("Scanout buffer not set\n");
		err = -EAGAIN;
		goto unlock;
	}

	if (painter->was_update_requested) {
		EVDI_WARN("(dev=%d) Update ready not sent,",
			  evdi->dev_index);
		EVDI_WARN(" but pixels are grabbed.\n");
	}

	fb = &efb->base;
	if (!efb->obj->vmapping) {
		if (evdi_gem_vmap(efb->obj) == -ENOMEM) {
			EVDI_ERROR("Failed to map scanout buffer\n");
			err = -EFAULT;
			goto unlock;
		}
		if (!efb->obj->vmapping) {
			EVDI_ERROR("Inexistent vmapping\n");
			err = -EFAULT;
			goto unlock;
		}
	}

	if (cmd->buf_width != fb->width ||
		cmd->buf_height != fb->height) {
		EVDI_ERROR("Invalid buffer dimension\n");
		err = -EINVAL;
		goto unlock;
	}

	if (cmd->num_rects < 1) {
		EVDI_ERROR("No space for clip rects\n");
		err = -EINVAL;
		goto unlock;
	}

	if (cmd->mode == EVDI_GRABPIX_MODE_DIRTY) {
		if (painter->num_dirts < 0) {
			err = -EAGAIN;
			goto unlock;
		}
		merge_dirty_rects(&painter->dirty_rects[0],
				  &painter->num_dirts);
		if (painter->num_dirts > cmd->num_rects)
			collapse_dirty_rects(&painter->dirty_rects[0],
						 &painter->num_dirts);

		cmd->num_rects = painter->num_dirts;

		if (copy_to_user(cmd->rects, painter->dirty_rects,
			cmd->num_rects * sizeof(cmd->rects[0])))
			err = -EFAULT;
		if (err == 0)
			err = copy_primary_pixels(efb,
						  cmd->buffer,
						  cmd->buf_byte_stride,
						  painter->num_dirts,
						  painter->dirty_rects,
						  cmd->buf_width,
						  cmd->buf_height);
		if (err == 0)
			copy_cursor_pixels(efb,
					   cmd->buffer,
					   cmd->buf_byte_stride,
					   evdi->cursor);

		painter->num_dirts = 0;
	}
unlock:
	painter_unlock(painter);

	return err;
}

int evdi_painter_request_update_ioctl(struct drm_device *drm_dev,
				      __always_unused void *data,
				      __always_unused struct drm_file *file)
{
	struct evdi_device *evdi = drm_dev->dev_private;
	struct evdi_painter *painter = evdi->painter;
	int result = 0;

	if (painter) {
		painter_lock(painter);

		if (painter->was_update_requested) {
			EVDI_WARN
			  ("(dev=%d) Update was already requested - ignoring\n",
			   evdi->dev_index);
		} else {
			if (painter->num_dirts > 0)
				result = 1;
			else
				painter->was_update_requested = true;
		}

		painter_unlock(painter);

		return result;
	} else {
		return -ENODEV;
	}
}

int evdi_painter_init(struct evdi_device *dev)
{
	EVDI_CHECKPT();
	dev->painter = kzalloc(sizeof(*dev->painter), GFP_KERNEL);
	if (dev->painter) {
		mutex_init(&dev->painter->lock);
		mutex_init(&dev->painter->new_scanout_fb_lock);
		dev->painter->edid = NULL;
		dev->painter->edid_length = 0;
		dev->painter->needs_full_modeset = true;
		return 0;
	}
	return -ENOMEM;
}

void evdi_painter_cleanup(struct evdi_device *evdi)
{
	struct evdi_painter *painter = evdi->painter;

	EVDI_CHECKPT();
	if (painter) {
		painter_lock(painter);
		kfree(painter->edid);
		painter->edid_length = 0;
		painter->edid = 0;
		painter_unlock(painter);
	} else {
		EVDI_WARN("Painter does not exist\n");
	}
}

/*
 * This can be called from multiple threads so we need to lock during
 * *new_scanout_fb* assignment.
 * It is called from *evdi_crtc_page_flip* which must return immediately.
 * If we lock here whole painter object it will interfere with grab_pics
 * ioctl (which can take some time).
 * Because of that we lock only on the *new_scanout_fb*.
 */
void evdi_painter_set_new_scanout_buffer(struct evdi_device *evdi,
					 struct evdi_framebuffer *newfb)
{
	struct evdi_painter *painter = evdi->painter;
	struct evdi_framebuffer *oldfb = NULL;

	if (newfb)
		drm_framebuffer_reference(&newfb->base);

	mutex_lock(&painter->new_scanout_fb_lock);
	oldfb = painter->new_scanout_fb;
	painter->new_scanout_fb = newfb;
	mutex_unlock(&painter->new_scanout_fb_lock);

	if (oldfb)
		drm_framebuffer_unreference(&oldfb->base);
}

void evdi_painter_commit_scanout_buffer(struct evdi_device *evdi)
{
	struct evdi_painter *painter = evdi->painter;
	struct evdi_framebuffer *newfb = NULL;
	struct evdi_framebuffer *oldfb = NULL;

	painter_lock(painter);
	mutex_lock(&painter->new_scanout_fb_lock);

	newfb = painter->new_scanout_fb;

	if (newfb)
		drm_framebuffer_reference(&newfb->base);

	oldfb = painter->scanout_fb;
	painter->scanout_fb = newfb;

	mutex_unlock(&painter->new_scanout_fb_lock);
	painter_unlock(painter);

	if (oldfb)
		drm_framebuffer_unreference(&oldfb->base);
}

bool evdi_painter_needs_full_modeset(struct evdi_device *evdi)
{
	struct evdi_painter *painter = evdi->painter;

	if (painter)
		return painter->needs_full_modeset;
	return false;
}