/**************************************************************************
 *
 * Copyright © 2007 David Airlie
 * Copyright © 2009-2015 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.
 *
 **************************************************************************/

#include <linux/pci.h>

#include <drm/drm_fourcc.h>
#include <drm/ttm/ttm_placement.h>

#include "vmwgfx_drv.h"
#include "vmwgfx_kms.h"

#define VMW_DIRTY_DELAY (HZ / 30)

struct vmw_fb_par {
        struct vmw_private *vmw_priv;

        void *vmalloc;

        struct mutex bo_mutex;
        struct vmw_buffer_object *vmw_bo;
        unsigned bo_size;
        struct drm_framebuffer *set_fb;
        struct drm_display_mode *set_mode;
        u32 fb_x;
        u32 fb_y;
        bool bo_iowrite;

        u32 pseudo_palette[17];

        unsigned max_width;
        unsigned max_height;

        struct {
                spinlock_t lock;
                bool active;
                unsigned x1;
                unsigned y1;
                unsigned x2;
                unsigned y2;
        } dirty;

        struct drm_crtc *crtc;
        struct drm_connector *con;
        struct delayed_work local_work;
};

static int vmw_fb_setcolreg(unsigned regno, unsigned red, unsigned green,
                            unsigned blue, unsigned transp,
                            struct fb_info *info)
{
        struct vmw_fb_par *par = info->par;
        u32 *pal = par->pseudo_palette;

        if (regno > 15) {
                DRM_ERROR("Bad regno %u.\n", regno);
                return 1;
        }

        switch (par->set_fb->format->depth) {
        case 24:
        case 32:
                pal[regno] = ((red & 0xff00) << 8) |
                              (green & 0xff00) |
                             ((blue  & 0xff00) >> 8);
                break;
        default:
                DRM_ERROR("Bad depth %u, bpp %u.\n",
                          par->set_fb->format->depth,
                          par->set_fb->format->cpp[0] * 8);
                return 1;
        }

        return 0;
}

static int vmw_fb_check_var(struct fb_var_screeninfo *var,
                            struct fb_info *info)
{
        int depth = var->bits_per_pixel;
        struct vmw_fb_par *par = info->par;
        struct vmw_private *vmw_priv = par->vmw_priv;

        switch (var->bits_per_pixel) {
        case 32:
                depth = (var->transp.length > 0) ? 32 : 24;
                break;
        default:
                DRM_ERROR("Bad bpp %u.\n", var->bits_per_pixel);
                return -EINVAL;
        }

        switch (depth) {
        case 24:
                var->red.offset = 16;
                var->green.offset = 8;
                var->blue.offset = 0;
                var->red.length = 8;
                var->green.length = 8;
                var->blue.length = 8;
                var->transp.length = 0;
                var->transp.offset = 0;
                break;
        case 32:
                var->red.offset = 16;
                var->green.offset = 8;
                var->blue.offset = 0;
                var->red.length = 8;
                var->green.length = 8;
                var->blue.length = 8;
                var->transp.length = 8;
                var->transp.offset = 24;
                break;
        default:
                DRM_ERROR("Bad depth %u.\n", depth);
                return -EINVAL;
        }

        if ((var->xoffset + var->xres) > par->max_width ||
            (var->yoffset + var->yres) > par->max_height) {
                DRM_ERROR("Requested geom can not fit in framebuffer\n");
                return -EINVAL;
        }

        if (!vmw_kms_validate_mode_vram(vmw_priv,
                                        var->xres * var->bits_per_pixel/8,
                                        var->yoffset + var->yres)) {
                DRM_ERROR("Requested geom can not fit in framebuffer\n");
                return -EINVAL;
        }

        return 0;
}

static int vmw_fb_blank(int blank, struct fb_info *info)
{
        return 0;
}

/**
 * vmw_fb_dirty_flush - flush dirty regions to the kms framebuffer
 *
 * @work: The struct work_struct associated with this task.
 *
 * This function flushes the dirty regions of the vmalloc framebuffer to the
 * kms framebuffer, and if the kms framebuffer is visible, also updated the
 * corresponding displays. Note that this function runs even if the kms
 * framebuffer is not bound to a crtc and thus not visible, but it's turned
 * off during hibernation using the par->dirty.active bool.
 */
static void vmw_fb_dirty_flush(struct work_struct *work)
{
        struct vmw_fb_par *par = container_of(work, struct vmw_fb_par,
                                              local_work.work);
        struct vmw_private *vmw_priv = par->vmw_priv;
        struct fb_info *info = vmw_priv->fb_info;
        unsigned long irq_flags;
        s32 dst_x1, dst_x2, dst_y1, dst_y2, w = 0, h = 0;
        u32 cpp, max_x, max_y;
        struct drm_clip_rect clip;
        struct drm_framebuffer *cur_fb;
        u8 *src_ptr, *dst_ptr;
        struct vmw_buffer_object *vbo = par->vmw_bo;
        void *virtual;

        if (!READ_ONCE(par->dirty.active))
                return;

        mutex_lock(&par->bo_mutex);
        cur_fb = par->set_fb;
        if (!cur_fb)
                goto out_unlock;

        (void) ttm_bo_reserve(&vbo->base, false, false, NULL);
        virtual = vmw_bo_map_and_cache(vbo);
        if (!virtual)
                goto out_unreserve;

        spin_lock_irqsave(&par->dirty.lock, irq_flags);
        if (!par->dirty.active) {
                spin_unlock_irqrestore(&par->dirty.lock, irq_flags);
                goto out_unreserve;
        }

        /*
         * Handle panning when copying from vmalloc to framebuffer.
         * Clip dirty area to framebuffer.
         */
        cpp = cur_fb->format->cpp[0];
        max_x = par->fb_x + cur_fb->width;
        max_y = par->fb_y + cur_fb->height;

        dst_x1 = par->dirty.x1 - par->fb_x;
        dst_y1 = par->dirty.y1 - par->fb_y;
        dst_x1 = max_t(s32, dst_x1, 0);
        dst_y1 = max_t(s32, dst_y1, 0);

        dst_x2 = par->dirty.x2 - par->fb_x;
        dst_y2 = par->dirty.y2 - par->fb_y;
        dst_x2 = min_t(s32, dst_x2, max_x);
        dst_y2 = min_t(s32, dst_y2, max_y);
        w = dst_x2 - dst_x1;
        h = dst_y2 - dst_y1;
        w = max_t(s32, 0, w);
        h = max_t(s32, 0, h);

        par->dirty.x1 = par->dirty.x2 = 0;
        par->dirty.y1 = par->dirty.y2 = 0;
        spin_unlock_irqrestore(&par->dirty.lock, irq_flags);

        if (w && h) {
                dst_ptr = (u8 *)virtual  +
                        (dst_y1 * par->set_fb->pitches[0] + dst_x1 * cpp);
                src_ptr = (u8 *)par->vmalloc +
                        ((dst_y1 + par->fb_y) * info->fix.line_length +
                         (dst_x1 + par->fb_x) * cpp);

                while (h-- > 0) {
                        memcpy(dst_ptr, src_ptr, w*cpp);
                        dst_ptr += par->set_fb->pitches[0];
                        src_ptr += info->fix.line_length;
                }

                clip.x1 = dst_x1;
                clip.x2 = dst_x2;
                clip.y1 = dst_y1;
                clip.y2 = dst_y2;
        }

out_unreserve:
        ttm_bo_unreserve(&vbo->base);
        if (w && h) {
                WARN_ON_ONCE(par->set_fb->funcs->dirty(cur_fb, NULL, 0, 0,
                                                       &clip, 1));
                vmw_cmd_flush(vmw_priv, false);
        }
out_unlock:
        mutex_unlock(&par->bo_mutex);
}

static void vmw_fb_dirty_mark(struct vmw_fb_par *par,
                              unsigned x1, unsigned y1,
                              unsigned width, unsigned height)
{
        unsigned long flags;
        unsigned x2 = x1 + width;
        unsigned y2 = y1 + height;

        spin_lock_irqsave(&par->dirty.lock, flags);
        if (par->dirty.x1 == par->dirty.x2) {
                par->dirty.x1 = x1;
                par->dirty.y1 = y1;
                par->dirty.x2 = x2;
                par->dirty.y2 = y2;
                /* if we are active start the dirty work
                 * we share the work with the defio system */
                if (par->dirty.active)
                        schedule_delayed_work(&par->local_work,
                                              VMW_DIRTY_DELAY);
        } else {
                if (x1 < par->dirty.x1)
                        par->dirty.x1 = x1;
                if (y1 < par->dirty.y1)
                        par->dirty.y1 = y1;
                if (x2 > par->dirty.x2)
                        par->dirty.x2 = x2;
                if (y2 > par->dirty.y2)
                        par->dirty.y2 = y2;
        }
        spin_unlock_irqrestore(&par->dirty.lock, flags);
}

static int vmw_fb_pan_display(struct fb_var_screeninfo *var,
                              struct fb_info *info)
{
        struct vmw_fb_par *par = info->par;

        if ((var->xoffset + var->xres) > var->xres_virtual ||
            (var->yoffset + var->yres) > var->yres_virtual) {
                DRM_ERROR("Requested panning can not fit in framebuffer\n");
                return -EINVAL;
        }

        mutex_lock(&par->bo_mutex);
        par->fb_x = var->xoffset;
        par->fb_y = var->yoffset;
        if (par->set_fb)
                vmw_fb_dirty_mark(par, par->fb_x, par->fb_y, par->set_fb->width,
                                  par->set_fb->height);
        mutex_unlock(&par->bo_mutex);

        return 0;
}

static void vmw_deferred_io(struct fb_info *info,
                            struct list_head *pagelist)
{
        struct vmw_fb_par *par = info->par;
        unsigned long start, end, min, max;
        unsigned long flags;
        struct page *page;
        int y1, y2;

        min = ULONG_MAX;
        max = 0;
        list_for_each_entry(page, pagelist, lru) {
                start = page->index << PAGE_SHIFT;
                end = start + PAGE_SIZE - 1;
                min = min(min, start);
                max = max(max, end);
        }

        if (min < max) {
                y1 = min / info->fix.line_length;
                y2 = (max / info->fix.line_length) + 1;

                spin_lock_irqsave(&par->dirty.lock, flags);
                par->dirty.x1 = 0;
                par->dirty.y1 = y1;
                par->dirty.x2 = info->var.xres;
                par->dirty.y2 = y2;
                spin_unlock_irqrestore(&par->dirty.lock, flags);

                /*
                 * Since we've already waited on this work once, try to
                 * execute asap.
                 */
                cancel_delayed_work(&par->local_work);
                schedule_delayed_work(&par->local_work, 0);
        }
};

static struct fb_deferred_io vmw_defio = {
        .delay          = VMW_DIRTY_DELAY,
        .deferred_io    = vmw_deferred_io,
};

/*
 * Draw code
 */

static void vmw_fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
{
        cfb_fillrect(info, rect);
        vmw_fb_dirty_mark(info->par, rect->dx, rect->dy,
                          rect->width, rect->height);
}

static void vmw_fb_copyarea(struct fb_info *info, const struct fb_copyarea *region)
{
        cfb_copyarea(info, region);
        vmw_fb_dirty_mark(info->par, region->dx, region->dy,
                          region->width, region->height);
}

static void vmw_fb_imageblit(struct fb_info *info, const struct fb_image *image)
{
        cfb_imageblit(info, image);
        vmw_fb_dirty_mark(info->par, image->dx, image->dy,
                          image->width, image->height);
}

/*
 * Bring up code
 */

static int vmw_fb_create_bo(struct vmw_private *vmw_priv,
                            size_t size, struct vmw_buffer_object **out)
{
        struct vmw_buffer_object *vmw_bo;
        int ret;

        ret = vmw_bo_create(vmw_priv, size,
                              &vmw_sys_placement,
                              false, false,
                              &vmw_bo_bo_free, &vmw_bo);
        if (unlikely(ret != 0))
                return ret;

        *out = vmw_bo;

        return ret;
}

static int vmw_fb_compute_depth(struct fb_var_screeninfo *var,
                                int *depth)
{
        switch (var->bits_per_pixel) {
        case 32:
                *depth = (var->transp.length > 0) ? 32 : 24;
                break;
        default:
                DRM_ERROR("Bad bpp %u.\n", var->bits_per_pixel);
                return -EINVAL;
        }

        return 0;
}

static int vmwgfx_set_config_internal(struct drm_mode_set *set)
{
        struct drm_crtc *crtc = set->crtc;
        struct drm_modeset_acquire_ctx ctx;
        int ret;

        drm_modeset_acquire_init(&ctx, 0);

restart:
        ret = crtc->funcs->set_config(set, &ctx);

        if (ret == -EDEADLK) {
                drm_modeset_backoff(&ctx);
                goto restart;
        }

        drm_modeset_drop_locks(&ctx);
        drm_modeset_acquire_fini(&ctx);

        return ret;
}

static int vmw_fb_kms_detach(struct vmw_fb_par *par,
                             bool detach_bo,
                             bool unref_bo)
{
        struct drm_framebuffer *cur_fb = par->set_fb;
        int ret;

        /* Detach the KMS framebuffer from crtcs */
        if (par->set_mode) {
                struct drm_mode_set set;

                set.crtc = par->crtc;
                set.x = 0;
                set.y = 0;
                set.mode = NULL;
                set.fb = NULL;
                set.num_connectors = 0;
                set.connectors = &par->con;
                ret = vmwgfx_set_config_internal(&set);
                if (ret) {
                        DRM_ERROR("Could not unset a mode.\n");
                        return ret;
                }
                drm_mode_destroy(&par->vmw_priv->drm, par->set_mode);
                par->set_mode = NULL;
        }

        if (cur_fb) {
                drm_framebuffer_put(cur_fb);
                par->set_fb = NULL;
        }

        if (par->vmw_bo && detach_bo && unref_bo)
                vmw_bo_unreference(&par->vmw_bo);

        return 0;
}

static int vmw_fb_kms_framebuffer(struct fb_info *info)
{
        struct drm_mode_fb_cmd2 mode_cmd = {0};
        struct vmw_fb_par *par = info->par;
        struct fb_var_screeninfo *var = &info->var;
        struct drm_framebuffer *cur_fb;
        struct vmw_framebuffer *vfb;
        int ret = 0, depth;
        size_t new_bo_size;

        ret = vmw_fb_compute_depth(var, &depth);
        if (ret)
                return ret;

        mode_cmd.width = var->xres;
        mode_cmd.height = var->yres;
        mode_cmd.pitches[0] = ((var->bits_per_pixel + 7) / 8) * mode_cmd.width;
        mode_cmd.pixel_format =
                drm_mode_legacy_fb_format(var->bits_per_pixel, depth);

        cur_fb = par->set_fb;
        if (cur_fb && cur_fb->width == mode_cmd.width &&
            cur_fb->height == mode_cmd.height &&
            cur_fb->format->format == mode_cmd.pixel_format &&
            cur_fb->pitches[0] == mode_cmd.pitches[0])
                return 0;

        /* Need new buffer object ? */
        new_bo_size = (size_t) mode_cmd.pitches[0] * (size_t) mode_cmd.height;
        ret = vmw_fb_kms_detach(par,
                                par->bo_size < new_bo_size ||
                                par->bo_size > 2*new_bo_size,
                                true);
        if (ret)
                return ret;

        if (!par->vmw_bo) {
                ret = vmw_fb_create_bo(par->vmw_priv, new_bo_size,
                                       &par->vmw_bo);
                if (ret) {
                        DRM_ERROR("Failed creating a buffer object for "
                                  "fbdev.\n");
                        return ret;
                }
                par->bo_size = new_bo_size;
        }

        vfb = vmw_kms_new_framebuffer(par->vmw_priv, par->vmw_bo, NULL,
                                      true, &mode_cmd);
        if (IS_ERR(vfb))
                return PTR_ERR(vfb);

        par->set_fb = &vfb->base;

        return 0;
}

static int vmw_fb_set_par(struct fb_info *info)
{
        struct vmw_fb_par *par = info->par;
        struct vmw_private *vmw_priv = par->vmw_priv;
        struct drm_mode_set set;
        struct fb_var_screeninfo *var = &info->var;
        struct drm_display_mode new_mode = { DRM_MODE("fb_mode",
                DRM_MODE_TYPE_DRIVER,
                0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_PVSYNC)
        };
        struct drm_display_mode *mode;
        int ret;

        mode = drm_mode_duplicate(&vmw_priv->drm, &new_mode);
        if (!mode) {
                DRM_ERROR("Could not create new fb mode.\n");
                return -ENOMEM;
        }

        mode->hdisplay = var->xres;
        mode->vdisplay = var->yres;
        vmw_guess_mode_timing(mode);

        if (!vmw_kms_validate_mode_vram(vmw_priv,
                                        mode->hdisplay *
                                        DIV_ROUND_UP(var->bits_per_pixel, 8),
                                        mode->vdisplay)) {
                drm_mode_destroy(&vmw_priv->drm, mode);
                return -EINVAL;
        }

        mutex_lock(&par->bo_mutex);
        ret = vmw_fb_kms_framebuffer(info);
        if (ret)
                goto out_unlock;

        par->fb_x = var->xoffset;
        par->fb_y = var->yoffset;

        set.crtc = par->crtc;
        set.x = 0;
        set.y = 0;
        set.mode = mode;
        set.fb = par->set_fb;
        set.num_connectors = 1;
        set.connectors = &par->con;

        ret = vmwgfx_set_config_internal(&set);
        if (ret)
                goto out_unlock;

        vmw_fb_dirty_mark(par, par->fb_x, par->fb_y,
                          par->set_fb->width, par->set_fb->height);

        /* If there already was stuff dirty we wont
         * schedule a new work, so lets do it now */

        schedule_delayed_work(&par->local_work, 0);

out_unlock:
        if (par->set_mode)
                drm_mode_destroy(&vmw_priv->drm, par->set_mode);
        par->set_mode = mode;

        mutex_unlock(&par->bo_mutex);

        return ret;
}


static const struct fb_ops vmw_fb_ops = {
        .owner = THIS_MODULE,
        .fb_check_var = vmw_fb_check_var,
        .fb_set_par = vmw_fb_set_par,
        .fb_setcolreg = vmw_fb_setcolreg,
        .fb_fillrect = vmw_fb_fillrect,
        .fb_copyarea = vmw_fb_copyarea,
        .fb_imageblit = vmw_fb_imageblit,
        .fb_pan_display = vmw_fb_pan_display,
        .fb_blank = vmw_fb_blank,
};

int vmw_fb_init(struct vmw_private *vmw_priv)
{
        struct device *device = vmw_priv->drm.dev;
        struct vmw_fb_par *par;
        struct fb_info *info;
        unsigned fb_width, fb_height;
        unsigned int fb_bpp, fb_pitch, fb_size;
        struct drm_display_mode *init_mode;
        int ret;

        fb_bpp = 32;

        /* XXX As shouldn't these be as well. */
        fb_width = min(vmw_priv->fb_max_width, (unsigned)2048);
        fb_height = min(vmw_priv->fb_max_height, (unsigned)2048);

        fb_pitch = fb_width * fb_bpp / 8;
        fb_size = fb_pitch * fb_height;

        info = framebuffer_alloc(sizeof(*par), device);
        if (!info)
                return -ENOMEM;

        /*
         * Par
         */
        vmw_priv->fb_info = info;
        par = info->par;
        memset(par, 0, sizeof(*par));
        INIT_DELAYED_WORK(&par->local_work, &vmw_fb_dirty_flush);
        par->vmw_priv = vmw_priv;
        par->vmalloc = NULL;
        par->max_width = fb_width;
        par->max_height = fb_height;

        ret = vmw_kms_fbdev_init_data(vmw_priv, 0, par->max_width,
                                      par->max_height, &par->con,
                                      &par->crtc, &init_mode);
        if (ret)
                goto err_kms;

        info->var.xres = init_mode->hdisplay;
        info->var.yres = init_mode->vdisplay;

        /*
         * Create buffers and alloc memory
         */
        par->vmalloc = vzalloc(fb_size);
        if (unlikely(par->vmalloc == NULL)) {
                ret = -ENOMEM;
                goto err_free;
        }

        /*
         * Fixed and var
         */
        strcpy(info->fix.id, "svgadrmfb");
        info->fix.type = FB_TYPE_PACKED_PIXELS;
        info->fix.visual = FB_VISUAL_TRUECOLOR;
        info->fix.type_aux = 0;
        info->fix.xpanstep = 1; /* doing it in hw */
        info->fix.ypanstep = 1; /* doing it in hw */
        info->fix.ywrapstep = 0;
        info->fix.accel = FB_ACCEL_NONE;
        info->fix.line_length = fb_pitch;

        info->fix.smem_start = 0;
        info->fix.smem_len = fb_size;

        info->pseudo_palette = par->pseudo_palette;
        info->screen_base = (char __iomem *)par->vmalloc;
        info->screen_size = fb_size;

        info->fbops = &vmw_fb_ops;

        /* 24 depth per default */
        info->var.red.offset = 16;
        info->var.green.offset = 8;
        info->var.blue.offset = 0;
        info->var.red.length = 8;
        info->var.green.length = 8;
        info->var.blue.length = 8;
        info->var.transp.offset = 0;
        info->var.transp.length = 0;

        info->var.xres_virtual = fb_width;
        info->var.yres_virtual = fb_height;
        info->var.bits_per_pixel = fb_bpp;
        info->var.xoffset = 0;
        info->var.yoffset = 0;
        info->var.activate = FB_ACTIVATE_NOW;
        info->var.height = -1;
        info->var.width = -1;

        /* Use default scratch pixmap (info->pixmap.flags = FB_PIXMAP_SYSTEM) */
        info->apertures = alloc_apertures(1);
        if (!info->apertures) {
                ret = -ENOMEM;
                goto err_aper;
        }
        info->apertures->ranges[0].base = vmw_priv->vram_start;
        info->apertures->ranges[0].size = vmw_priv->vram_size;

        /*
         * Dirty & Deferred IO
         */
        par->dirty.x1 = par->dirty.x2 = 0;
        par->dirty.y1 = par->dirty.y2 = 0;
        par->dirty.active = true;
        spin_lock_init(&par->dirty.lock);
        mutex_init(&par->bo_mutex);
        info->fbdefio = &vmw_defio;
        fb_deferred_io_init(info);

        ret = register_framebuffer(info);
        if (unlikely(ret != 0))
                goto err_defio;

        vmw_fb_set_par(info);

        return 0;

err_defio:
        fb_deferred_io_cleanup(info);
err_aper:
err_free:
        vfree(par->vmalloc);
err_kms:
        framebuffer_release(info);
        vmw_priv->fb_info = NULL;

        return ret;
}

int vmw_fb_close(struct vmw_private *vmw_priv)
{
        struct fb_info *info;
        struct vmw_fb_par *par;

        if (!vmw_priv->fb_info)
                return 0;

        info = vmw_priv->fb_info;
        par = info->par;

        /* ??? order */
        fb_deferred_io_cleanup(info);
        cancel_delayed_work_sync(&par->local_work);
        unregister_framebuffer(info);

        mutex_lock(&par->bo_mutex);
        (void) vmw_fb_kms_detach(par, true, true);
        mutex_unlock(&par->bo_mutex);

        vfree(par->vmalloc);
        framebuffer_release(info);

        return 0;
}

int vmw_fb_off(struct vmw_private *vmw_priv)
{
        struct fb_info *info;
        struct vmw_fb_par *par;
        unsigned long flags;

        if (!vmw_priv->fb_info)
                return -EINVAL;

        info = vmw_priv->fb_info;
        par = info->par;

        spin_lock_irqsave(&par->dirty.lock, flags);
        par->dirty.active = false;
        spin_unlock_irqrestore(&par->dirty.lock, flags);

        flush_delayed_work(&info->deferred_work);
        flush_delayed_work(&par->local_work);

        return 0;
}

int vmw_fb_on(struct vmw_private *vmw_priv)
{
        struct fb_info *info;
        struct vmw_fb_par *par;
        unsigned long flags;

        if (!vmw_priv->fb_info)
                return -EINVAL;

        info = vmw_priv->fb_info;
        par = info->par;

        spin_lock_irqsave(&par->dirty.lock, flags);
        par->dirty.active = true;
        spin_unlock_irqrestore(&par->dirty.lock, flags);

        /*
         * Need to reschedule a dirty update, because otherwise that's
         * only done in dirty_mark() if the previous coalesced
         * dirty region was empty.
         */
        schedule_delayed_work(&par->local_work, 0);

        return 0;
}