drivers/gpu/drm/vmwgfx/vmwgfx_fb.c

   1 /**************************************************************************
   2  *
   3  * Copyright © 2007 David Airlie
   4  * Copyright © 2009 VMware, Inc., Palo Alto, CA., USA
   5  * All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the
   9  * "Software"), to deal in the Software without restriction, including
  10  * without limitation the rights to use, copy, modify, merge, publish,
  11  * distribute, sub license, and/or sell copies of the Software, and to
  12  * permit persons to whom the Software is furnished to do so, subject to
  13  * the following conditions:
  14  *
  15  * The above copyright notice and this permission notice (including the
  16  * next paragraph) shall be included in all copies or substantial portions
  17  * of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  22  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  23  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  24  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  25  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  26  *
  27  **************************************************************************/
  28
  29 #include <linux/export.h>
  30
  31 #include <drm/drmP.h>
  32 #include "vmwgfx_drv.h"
  33
  34 #include <drm/ttm/ttm_placement.h>
  35
  36 #define VMW_DIRTY_DELAY (HZ / 30)
  37
  38 struct vmw_fb_par {
  39         struct vmw_private *vmw_priv;
  40
  41         void *vmalloc;
  42
  43         struct vmw_dma_buffer *vmw_bo;
  44         struct ttm_bo_kmap_obj map;
  45
  46         u32 pseudo_palette[17];
  47
  48         unsigned depth;
  49         unsigned bpp;
  50
  51         unsigned max_width;
  52         unsigned max_height;
  53
  54         void *bo_ptr;
  55         unsigned bo_size;
  56         bool bo_iowrite;
  57
  58         struct {
  59                 spinlock_t lock;
  60                 bool active;
  61                 unsigned x1;
  62                 unsigned y1;
  63                 unsigned x2;
  64                 unsigned y2;
  65         } dirty;
  66 };
  67
  68 static int vmw_fb_setcolreg(unsigned regno, unsigned red, unsigned green,
  69                             unsigned blue, unsigned transp,
  70                             struct fb_info *info)
  71 {
  72         struct vmw_fb_par *par = info->par;
  73         u32 *pal = par->pseudo_palette;
  74
  75         if (regno > 15) {
  76                 DRM_ERROR("Bad regno %u.\n", regno);
  77                 return 1;
  78         }
  79
  80         switch (par->depth) {
  81         case 24:
  82         case 32:
  83                 pal[regno] = ((red & 0xff00) << 8) |
  84                               (green & 0xff00) |
  85                              ((blue  & 0xff00) >> 8);
  86                 break;
  87         default:
  88                 DRM_ERROR("Bad depth %u, bpp %u.\n", par->depth, par->bpp);
  89                 return 1;
  90         }
  91
  92         return 0;
  93 }
  94
  95 static int vmw_fb_check_var(struct fb_var_screeninfo *var,
  96                             struct fb_info *info)
  97 {
  98         int depth = var->bits_per_pixel;
  99         struct vmw_fb_par *par = info->par;
 100         struct vmw_private *vmw_priv = par->vmw_priv;
 101
 102         switch (var->bits_per_pixel) {
 103         case 32:
 104                 depth = (var->transp.length > 0) ? 32 : 24;
 105                 break;
 106         default:
 107                 DRM_ERROR("Bad bpp %u.\n", var->bits_per_pixel);
 108                 return -EINVAL;
 109         }
 110
 111         switch (depth) {
 112         case 24:
 113                 var->red.offset = 16;
 114                 var->green.offset = 8;
 115                 var->blue.offset = 0;
 116                 var->red.length = 8;
 117                 var->green.length = 8;
 118                 var->blue.length = 8;
 119                 var->transp.length = 0;
 120                 var->transp.offset = 0;
 121                 break;
 122         case 32:
 123                 var->red.offset = 16;
 124                 var->green.offset = 8;
 125                 var->blue.offset = 0;
 126                 var->red.length = 8;
 127                 var->green.length = 8;
 128                 var->blue.length = 8;
 129                 var->transp.length = 8;
 130                 var->transp.offset = 24;
 131                 break;
 132         default:
 133                 DRM_ERROR("Bad depth %u.\n", depth);
 134                 return -EINVAL;
 135         }
 136
 137         if (!(vmw_priv->capabilities & SVGA_CAP_DISPLAY_TOPOLOGY) &&
 138             (var->xoffset != 0 || var->yoffset != 0)) {
 139                 DRM_ERROR("Can not handle panning without display topology\n");
 140                 return -EINVAL;
 141         }
 142
 143         if ((var->xoffset + var->xres) > par->max_width ||
 144             (var->yoffset + var->yres) > par->max_height) {
 145                 DRM_ERROR("Requested geom can not fit in framebuffer\n");
 146                 return -EINVAL;
 147         }
 148
 149         if (!vmw_kms_validate_mode_vram(vmw_priv,
 150                                         info->fix.line_length,
 151                                         var->yoffset + var->yres)) {
 152                 DRM_ERROR("Requested geom can not fit in framebuffer\n");
 153                 return -EINVAL;
 154         }
 155
 156         return 0;
 157 }
 158
 159 static int vmw_fb_set_par(struct fb_info *info)
 160 {
 161         struct vmw_fb_par *par = info->par;
 162         struct vmw_private *vmw_priv = par->vmw_priv;
 163         int ret;
 164
 165         ret = vmw_kms_write_svga(vmw_priv, info->var.xres, info->var.yres,
 166                                  info->fix.line_length,
 167                                  par->bpp, par->depth);
 168         if (ret)
 169                 return ret;
 170
 171         if (vmw_priv->capabilities & SVGA_CAP_DISPLAY_TOPOLOGY) {
 172                 /* TODO check if pitch and offset changes */
 173                 vmw_write(vmw_priv, SVGA_REG_NUM_GUEST_DISPLAYS, 1);
 174                 vmw_write(vmw_priv, SVGA_REG_DISPLAY_ID, 0);
 175                 vmw_write(vmw_priv, SVGA_REG_DISPLAY_IS_PRIMARY, true);
 176                 vmw_write(vmw_priv, SVGA_REG_DISPLAY_POSITION_X, info->var.xoffset);
 177                 vmw_write(vmw_priv, SVGA_REG_DISPLAY_POSITION_Y, info->var.yoffset);
 178                 vmw_write(vmw_priv, SVGA_REG_DISPLAY_WIDTH, info->var.xres);
 179                 vmw_write(vmw_priv, SVGA_REG_DISPLAY_HEIGHT, info->var.yres);
 180                 vmw_write(vmw_priv, SVGA_REG_DISPLAY_ID, SVGA_ID_INVALID);
 181         }
 182
 183         /* This is really helpful since if this fails the user
 184          * can probably not see anything on the screen.
 185          */
 186         WARN_ON(vmw_read(vmw_priv, SVGA_REG_FB_OFFSET) != 0);
 187
 188         return 0;
 189 }
 190
 191 static int vmw_fb_pan_display(struct fb_var_screeninfo *var,
 192                               struct fb_info *info)
 193 {
 194         return 0;
 195 }
 196
 197 static int vmw_fb_blank(int blank, struct fb_info *info)
 198 {
 199         return 0;
 200 }
 201
 202 /*
 203  * Dirty code
 204  */
 205
 206 static void vmw_fb_dirty_flush(struct vmw_fb_par *par)
 207 {
 208         struct vmw_private *vmw_priv = par->vmw_priv;
 209         struct fb_info *info = vmw_priv->fb_info;
 210         int stride = (info->fix.line_length / 4);
 211         int *src = (int *)info->screen_base;
 212         __le32 __iomem *vram_mem = par->bo_ptr;
 213         unsigned long flags;
 214         unsigned x, y, w, h;
 215         int i, k;
 216         struct {
 217                 uint32_t header;
 218                 SVGAFifoCmdUpdate body;
 219         } *cmd;
 220
 221         if (vmw_priv->suspended)
 222                 return;
 223
 224         spin_lock_irqsave(&par->dirty.lock, flags);
 225         if (!par->dirty.active) {
 226                 spin_unlock_irqrestore(&par->dirty.lock, flags);
 227                 return;
 228         }
 229         x = par->dirty.x1;
 230         y = par->dirty.y1;
 231         w = min(par->dirty.x2, info->var.xres) - x;
 232         h = min(par->dirty.y2, info->var.yres) - y;
 233         par->dirty.x1 = par->dirty.x2 = 0;
 234         par->dirty.y1 = par->dirty.y2 = 0;
 235         spin_unlock_irqrestore(&par->dirty.lock, flags);
 236
 237         for (i = y * stride; i < info->fix.smem_len / 4; i += stride) {
 238                 for (k = i+x; k < i+x+w && k < info->fix.smem_len / 4; k++)
 239                         iowrite32(src[k], vram_mem + k);
 240         }
 241
 242 #if 0
 243         DRM_INFO("%s, (%u, %u) (%ux%u)\n", __func__, x, y, w, h);
 244 #endif
 245
 246         cmd = vmw_fifo_reserve(vmw_priv, sizeof(*cmd));
 247         if (unlikely(cmd == NULL)) {
 248                 DRM_ERROR("Fifo reserve failed.\n");
 249                 return;
 250         }
 251
 252         cmd->header = cpu_to_le32(SVGA_CMD_UPDATE);
 253         cmd->body.x = cpu_to_le32(x);
 254         cmd->body.y = cpu_to_le32(y);
 255         cmd->body.width = cpu_to_le32(w);
 256         cmd->body.height = cpu_to_le32(h);
 257         vmw_fifo_commit(vmw_priv, sizeof(*cmd));
 258 }
 259
 260 static void vmw_fb_dirty_mark(struct vmw_fb_par *par,
 261                               unsigned x1, unsigned y1,
 262                               unsigned width, unsigned height)
 263 {
 264         struct fb_info *info = par->vmw_priv->fb_info;
 265         unsigned long flags;
 266         unsigned x2 = x1 + width;
 267         unsigned y2 = y1 + height;
 268
 269         spin_lock_irqsave(&par->dirty.lock, flags);
 270         if (par->dirty.x1 == par->dirty.x2) {
 271                 par->dirty.x1 = x1;
 272                 par->dirty.y1 = y1;
 273                 par->dirty.x2 = x2;
 274                 par->dirty.y2 = y2;
 275                 /* if we are active start the dirty work
 276                  * we share the work with the defio system */
 277                 if (par->dirty.active)
 278                         schedule_delayed_work(&info->deferred_work, VMW_DIRTY_DELAY);
 279         } else {
 280                 if (x1 < par->dirty.x1)
 281                         par->dirty.x1 = x1;
 282                 if (y1 < par->dirty.y1)
 283                         par->dirty.y1 = y1;
 284                 if (x2 > par->dirty.x2)
 285                         par->dirty.x2 = x2;
 286                 if (y2 > par->dirty.y2)
 287                         par->dirty.y2 = y2;
 288         }
 289         spin_unlock_irqrestore(&par->dirty.lock, flags);
 290 }
 291
 292 static void vmw_deferred_io(struct fb_info *info,
 293                             struct list_head *pagelist)
 294 {
 295         struct vmw_fb_par *par = info->par;
 296         unsigned long start, end, min, max;
 297         unsigned long flags;
 298         struct page *page;
 299         int y1, y2;
 300
 301         min = ULONG_MAX;
 302         max = 0;
 303         list_for_each_entry(page, pagelist, lru) {
 304                 start = page->index << PAGE_SHIFT;
 305                 end = start + PAGE_SIZE - 1;
 306                 min = min(min, start);
 307                 max = max(max, end);
 308         }
 309
 310         if (min < max) {
 311                 y1 = min / info->fix.line_length;
 312                 y2 = (max / info->fix.line_length) + 1;
 313
 314                 spin_lock_irqsave(&par->dirty.lock, flags);
 315                 par->dirty.x1 = 0;
 316                 par->dirty.y1 = y1;
 317                 par->dirty.x2 = info->var.xres;
 318                 par->dirty.y2 = y2;
 319                 spin_unlock_irqrestore(&par->dirty.lock, flags);
 320         }
 321
 322         vmw_fb_dirty_flush(par);
 323 };
 324
 325 struct fb_deferred_io vmw_defio = {
 326         .delay          = VMW_DIRTY_DELAY,
 327         .deferred_io    = vmw_deferred_io,
 328 };
 329
 330 /*
 331  * Draw code
 332  */
 333
 334 static void vmw_fb_fillrect(struct fb_info *info, const struct fb_fillrect *rect)
 335 {
 336         cfb_fillrect(info, rect);
 337         vmw_fb_dirty_mark(info->par, rect->dx, rect->dy,
 338                           rect->width, rect->height);
 339 }
 340
 341 static void vmw_fb_copyarea(struct fb_info *info, const struct fb_copyarea *region)
 342 {
 343         cfb_copyarea(info, region);
 344         vmw_fb_dirty_mark(info->par, region->dx, region->dy,
 345                           region->width, region->height);
 346 }
 347
 348 static void vmw_fb_imageblit(struct fb_info *info, const struct fb_image *image)
 349 {
 350         cfb_imageblit(info, image);
 351         vmw_fb_dirty_mark(info->par, image->dx, image->dy,
 352                           image->width, image->height);
 353 }
 354
 355 /*
 356  * Bring up code
 357  */
 358
 359 static struct fb_ops vmw_fb_ops = {
 360         .owner = THIS_MODULE,
 361         .fb_check_var = vmw_fb_check_var,
 362         .fb_set_par = vmw_fb_set_par,
 363         .fb_setcolreg = vmw_fb_setcolreg,
 364         .fb_fillrect = vmw_fb_fillrect,
 365         .fb_copyarea = vmw_fb_copyarea,
 366         .fb_imageblit = vmw_fb_imageblit,
 367         .fb_pan_display = vmw_fb_pan_display,
 368         .fb_blank = vmw_fb_blank,
 369 };
 370
 371 static int vmw_fb_create_bo(struct vmw_private *vmw_priv,
 372                             size_t size, struct vmw_dma_buffer **out)
 373 {
 374         struct vmw_dma_buffer *vmw_bo;
 375         struct ttm_placement ne_placement = vmw_vram_ne_placement;
 376         int ret;
 377
 378         ne_placement.lpfn = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 379
 380         /* interuptable? */
 381         ret = ttm_write_lock(&vmw_priv->fbdev_master.lock, false);
 382         if (unlikely(ret != 0))
 383                 return ret;
 384
 385         vmw_bo = kmalloc(sizeof(*vmw_bo), GFP_KERNEL);
 386         if (!vmw_bo)
 387                 goto err_unlock;
 388
 389         ret = vmw_dmabuf_init(vmw_priv, vmw_bo, size,
 390                               &ne_placement,
 391                               false,
 392                               &vmw_dmabuf_bo_free);
 393         if (unlikely(ret != 0))
 394                 goto err_unlock; /* init frees the buffer on failure */
 395
 396         *out = vmw_bo;
 397
 398         ttm_write_unlock(&vmw_priv->fbdev_master.lock);
 399
 400         return 0;
 401
 402 err_unlock:
 403         ttm_write_unlock(&vmw_priv->fbdev_master.lock);
 404         return ret;
 405 }
 406
 407 int vmw_fb_init(struct vmw_private *vmw_priv)
 408 {
 409         struct device *device = &vmw_priv->dev->pdev->dev;
 410         struct vmw_fb_par *par;
 411         struct fb_info *info;
 412         unsigned initial_width, initial_height;
 413         unsigned fb_width, fb_height;
 414         unsigned fb_bpp, fb_depth, fb_offset, fb_pitch, fb_size;
 415         int ret;
 416
 417         fb_bpp = 32;
 418         fb_depth = 24;
 419
 420         /* XXX As shouldn't these be as well. */
 421         fb_width = min(vmw_priv->fb_max_width, (unsigned)2048);
 422         fb_height = min(vmw_priv->fb_max_height, (unsigned)2048);
 423
 424         initial_width = min(vmw_priv->initial_width, fb_width);
 425         initial_height = min(vmw_priv->initial_height, fb_height);
 426
 427         fb_pitch = fb_width * fb_bpp / 8;
 428         fb_size = fb_pitch * fb_height;
 429         fb_offset = vmw_read(vmw_priv, SVGA_REG_FB_OFFSET);
 430
 431         info = framebuffer_alloc(sizeof(*par), device);
 432         if (!info)
 433                 return -ENOMEM;
 434
 435         /*
 436          * Par
 437          */
 438         vmw_priv->fb_info = info;
 439         par = info->par;
 440         par->vmw_priv = vmw_priv;
 441         par->depth = fb_depth;
 442         par->bpp = fb_bpp;
 443         par->vmalloc = NULL;
 444         par->max_width = fb_width;
 445         par->max_height = fb_height;
 446
 447         /*
 448          * Create buffers and alloc memory
 449          */
 450         par->vmalloc = vmalloc(fb_size);
 451         if (unlikely(par->vmalloc == NULL)) {
 452                 ret = -ENOMEM;
 453                 goto err_free;
 454         }
 455
 456         ret = vmw_fb_create_bo(vmw_priv, fb_size, &par->vmw_bo);
 457         if (unlikely(ret != 0))
 458                 goto err_free;
 459
 460         ret = ttm_bo_kmap(&par->vmw_bo->base,
 461                           0,
 462                           par->vmw_bo->base.num_pages,
 463                           &par->map);
 464         if (unlikely(ret != 0))
 465                 goto err_unref;
 466         par->bo_ptr = ttm_kmap_obj_virtual(&par->map, &par->bo_iowrite);
 467         par->bo_size = fb_size;
 468
 469         /*
 470          * Fixed and var
 471          */
 472         strcpy(info->fix.id, "svgadrmfb");
 473         info->fix.type = FB_TYPE_PACKED_PIXELS;
 474         info->fix.visual = FB_VISUAL_TRUECOLOR;
 475         info->fix.type_aux = 0;
 476         info->fix.xpanstep = 1; /* doing it in hw */
 477         info->fix.ypanstep = 1; /* doing it in hw */
 478         info->fix.ywrapstep = 0;
 479         info->fix.accel = FB_ACCEL_NONE;
 480         info->fix.line_length = fb_pitch;
 481
 482         info->fix.smem_start = 0;
 483         info->fix.smem_len = fb_size;
 484
 485         info->pseudo_palette = par->pseudo_palette;
 486         info->screen_base = par->vmalloc;
 487         info->screen_size = fb_size;
 488
 489         info->flags = FBINFO_DEFAULT;
 490         info->fbops = &vmw_fb_ops;
 491
 492         /* 24 depth per default */
 493         info->var.red.offset = 16;
 494         info->var.green.offset = 8;
 495         info->var.blue.offset = 0;
 496         info->var.red.length = 8;
 497         info->var.green.length = 8;
 498         info->var.blue.length = 8;
 499         info->var.transp.offset = 0;
 500         info->var.transp.length = 0;
 501
 502         info->var.xres_virtual = fb_width;
 503         info->var.yres_virtual = fb_height;
 504         info->var.bits_per_pixel = par->bpp;
 505         info->var.xoffset = 0;
 506         info->var.yoffset = 0;
 507         info->var.activate = FB_ACTIVATE_NOW;
 508         info->var.height = -1;
 509         info->var.width = -1;
 510
 511         info->var.xres = initial_width;
 512         info->var.yres = initial_height;
 513
 514         /* Use default scratch pixmap (info->pixmap.flags = FB_PIXMAP_SYSTEM) */
 515
 516         info->apertures = alloc_apertures(1);
 517         if (!info->apertures) {
 518                 ret = -ENOMEM;
 519                 goto err_aper;
 520         }
 521         info->apertures->ranges[0].base = vmw_priv->vram_start;
 522         info->apertures->ranges[0].size = vmw_priv->vram_size;
 523
 524         /*
 525          * Dirty & Deferred IO
 526          */
 527         par->dirty.x1 = par->dirty.x2 = 0;
 528         par->dirty.y1 = par->dirty.y2 = 0;
 529         par->dirty.active = true;
 530         spin_lock_init(&par->dirty.lock);
 531         info->fbdefio = &vmw_defio;
 532         fb_deferred_io_init(info);
 533
 534         ret = register_framebuffer(info);
 535         if (unlikely(ret != 0))
 536                 goto err_defio;
 537
 538         return 0;
 539
 540 err_defio:
 541         fb_deferred_io_cleanup(info);
 542 err_aper:
 543         ttm_bo_kunmap(&par->map);
 544 err_unref:
 545         ttm_bo_unref((struct ttm_buffer_object **)&par->vmw_bo);
 546 err_free:
 547         vfree(par->vmalloc);
 548         framebuffer_release(info);
 549         vmw_priv->fb_info = NULL;
 550
 551         return ret;
 552 }
 553
 554 int vmw_fb_close(struct vmw_private *vmw_priv)
 555 {
 556         struct fb_info *info;
 557         struct vmw_fb_par *par;
 558         struct ttm_buffer_object *bo;
 559
 560         if (!vmw_priv->fb_info)
 561                 return 0;
 562
 563         info = vmw_priv->fb_info;
 564         par = info->par;
 565         bo = &par->vmw_bo->base;
 566         par->vmw_bo = NULL;
 567
 568         /* ??? order */
 569         fb_deferred_io_cleanup(info);
 570         unregister_framebuffer(info);
 571
 572         ttm_bo_kunmap(&par->map);
 573         ttm_bo_unref(&bo);
 574
 575         vfree(par->vmalloc);
 576         framebuffer_release(info);
 577
 578         return 0;
 579 }
 580
 581 int vmw_fb_off(struct vmw_private *vmw_priv)
 582 {
 583         struct fb_info *info;
 584         struct vmw_fb_par *par;
 585         unsigned long flags;
 586
 587         if (!vmw_priv->fb_info)
 588                 return -EINVAL;
 589
 590         info = vmw_priv->fb_info;
 591         par = info->par;
 592
 593         spin_lock_irqsave(&par->dirty.lock, flags);
 594         par->dirty.active = false;
 595         spin_unlock_irqrestore(&par->dirty.lock, flags);
 596
 597         flush_delayed_work(&info->deferred_work);
 598
 599         par->bo_ptr = NULL;
 600         ttm_bo_kunmap(&par->map);
 601
 602         vmw_dmabuf_unpin(vmw_priv, par->vmw_bo, false);
 603
 604         return 0;
 605 }
 606
 607 int vmw_fb_on(struct vmw_private *vmw_priv)
 608 {
 609         struct fb_info *info;
 610         struct vmw_fb_par *par;
 611         unsigned long flags;
 612         bool dummy;
 613         int ret;
 614
 615         if (!vmw_priv->fb_info)
 616                 return -EINVAL;
 617
 618         info = vmw_priv->fb_info;
 619         par = info->par;
 620
 621         /* we are already active */
 622         if (par->bo_ptr != NULL)
 623                 return 0;
 624
 625         /* Make sure that all overlays are stoped when we take over */
 626         vmw_overlay_stop_all(vmw_priv);
 627
 628         ret = vmw_dmabuf_to_start_of_vram(vmw_priv, par->vmw_bo, true, false);
 629         if (unlikely(ret != 0)) {
 630                 DRM_ERROR("could not move buffer to start of VRAM\n");
 631                 goto err_no_buffer;
 632         }
 633
 634         ret = ttm_bo_kmap(&par->vmw_bo->base,
 635                           0,
 636                           par->vmw_bo->base.num_pages,
 637                           &par->map);
 638         BUG_ON(ret != 0);
 639         par->bo_ptr = ttm_kmap_obj_virtual(&par->map, &dummy);
 640
 641         spin_lock_irqsave(&par->dirty.lock, flags);
 642         par->dirty.active = true;
 643         spin_unlock_irqrestore(&par->dirty.lock, flags);
 644
 645 err_no_buffer:
 646         vmw_fb_set_par(info);
 647
 648         vmw_fb_dirty_mark(par, 0, 0, info->var.xres, info->var.yres);
 649
 650         /* If there already was stuff dirty we wont
 651          * schedule a new work, so lets do it now */
 652         schedule_delayed_work(&info->deferred_work, 0);
 653
 654         return 0;
 655 }