root/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c

DEFINITIONS

1. guc_action_flush_log_complete
2. guc_action_flush_log
3. guc_action_control_log
4. log_to_guc
5. guc_log_enable_flush_events
6. guc_log_disable_flush_events
7. subbuf_start_callback
8. create_buf_file_callback
9. remove_buf_file_callback
10. guc_move_to_next_buf
11. guc_get_write_buffer
12. guc_check_log_buf_overflow
13. guc_get_log_buffer_size
14. guc_read_update_log_buffer
15. capture_logs_work
16. guc_log_map
17. guc_log_unmap
18. intel_guc_log_init_early
19. guc_log_relay_create
20. guc_log_relay_destroy
21. guc_log_capture_logs
22. __get_default_log_level
23. intel_guc_log_create
24. intel_guc_log_destroy
25. intel_guc_log_set_level
26. intel_guc_log_relay_enabled
27. intel_guc_log_relay_open
28. intel_guc_log_relay_flush
29. intel_guc_log_relay_close
30. intel_guc_log_handle_flush_event

   1 // SPDX-License-Identifier: MIT
   2 /*
   3  * Copyright © 2014-2019 Intel Corporation
   4  */
   5 
   6 #include <linux/debugfs.h>
   7 
   8 #include "gt/intel_gt.h"
   9 #include "i915_drv.h"
  10 #include "i915_memcpy.h"
  11 #include "intel_guc_log.h"
  12 
  13 static void guc_log_capture_logs(struct intel_guc_log *log);
  14 
  15 /**
  16  * DOC: GuC firmware log
  17  *
  18  * Firmware log is enabled by setting i915.guc_log_level to the positive level.
  19  * Log data is printed out via reading debugfs i915_guc_log_dump. Reading from
  20  * i915_guc_load_status will print out firmware loading status and scratch
  21  * registers value.
  22  */
  23 
  24 static int guc_action_flush_log_complete(struct intel_guc *guc)
  25 {
  26         u32 action[] = {
  27                 INTEL_GUC_ACTION_LOG_BUFFER_FILE_FLUSH_COMPLETE
  28         };
  29 
  30         return intel_guc_send(guc, action, ARRAY_SIZE(action));
  31 }
  32 
  33 static int guc_action_flush_log(struct intel_guc *guc)
  34 {
  35         u32 action[] = {
  36                 INTEL_GUC_ACTION_FORCE_LOG_BUFFER_FLUSH,
  37                 0
  38         };
  39 
  40         return intel_guc_send(guc, action, ARRAY_SIZE(action));
  41 }
  42 
  43 static int guc_action_control_log(struct intel_guc *guc, bool enable,
  44                                   bool default_logging, u32 verbosity)
  45 {
  46         u32 action[] = {
  47                 INTEL_GUC_ACTION_UK_LOG_ENABLE_LOGGING,
  48                 (enable ? GUC_LOG_CONTROL_LOGGING_ENABLED : 0) |
  49                 (verbosity << GUC_LOG_CONTROL_VERBOSITY_SHIFT) |
  50                 (default_logging ? GUC_LOG_CONTROL_DEFAULT_LOGGING : 0)
  51         };
  52 
  53         GEM_BUG_ON(verbosity > GUC_LOG_VERBOSITY_MAX);
  54 
  55         return intel_guc_send(guc, action, ARRAY_SIZE(action));
  56 }
  57 
  58 static inline struct intel_guc *log_to_guc(struct intel_guc_log *log)
  59 {
  60         return container_of(log, struct intel_guc, log);
  61 }
  62 
  63 static void guc_log_enable_flush_events(struct intel_guc_log *log)
  64 {
  65         intel_guc_enable_msg(log_to_guc(log),
  66                              INTEL_GUC_RECV_MSG_FLUSH_LOG_BUFFER |
  67                              INTEL_GUC_RECV_MSG_CRASH_DUMP_POSTED);
  68 }
  69 
  70 static void guc_log_disable_flush_events(struct intel_guc_log *log)
  71 {
  72         intel_guc_disable_msg(log_to_guc(log),
  73                               INTEL_GUC_RECV_MSG_FLUSH_LOG_BUFFER |
  74                               INTEL_GUC_RECV_MSG_CRASH_DUMP_POSTED);
  75 }
  76 
  77 /*
  78  * Sub buffer switch callback. Called whenever relay has to switch to a new
  79  * sub buffer, relay stays on the same sub buffer if 0 is returned.
  80  */
  81 static int subbuf_start_callback(struct rchan_buf *buf,
  82                                  void *subbuf,
  83                                  void *prev_subbuf,
  84                                  size_t prev_padding)
  85 {
  86         /*
  87          * Use no-overwrite mode by default, where relay will stop accepting
  88          * new data if there are no empty sub buffers left.
  89          * There is no strict synchronization enforced by relay between Consumer
  90          * and Producer. In overwrite mode, there is a possibility of getting
  91          * inconsistent/garbled data, the producer could be writing on to the
  92          * same sub buffer from which Consumer is reading. This can't be avoided
  93          * unless Consumer is fast enough and can always run in tandem with
  94          * Producer.
  95          */
  96         if (relay_buf_full(buf))
  97                 return 0;
  98 
  99         return 1;
 100 }
 101 
 102 /*
 103  * file_create() callback. Creates relay file in debugfs.
 104  */
 105 static struct dentry *create_buf_file_callback(const char *filename,
 106                                                struct dentry *parent,
 107                                                umode_t mode,
 108                                                struct rchan_buf *buf,
 109                                                int *is_global)
 110 {
 111         struct dentry *buf_file;
 112 
 113         /*
 114          * This to enable the use of a single buffer for the relay channel and
 115          * correspondingly have a single file exposed to User, through which
 116          * it can collect the logs in order without any post-processing.
 117          * Need to set 'is_global' even if parent is NULL for early logging.
 118          */
 119         *is_global = 1;
 120 
 121         if (!parent)
 122                 return NULL;
 123 
 124         buf_file = debugfs_create_file(filename, mode,
 125                                        parent, buf, &relay_file_operations);
 126         if (IS_ERR(buf_file))
 127                 return NULL;
 128 
 129         return buf_file;
 130 }
 131 
 132 /*
 133  * file_remove() default callback. Removes relay file in debugfs.
 134  */
 135 static int remove_buf_file_callback(struct dentry *dentry)
 136 {
 137         debugfs_remove(dentry);
 138         return 0;
 139 }
 140 
 141 /* relay channel callbacks */
 142 static struct rchan_callbacks relay_callbacks = {
 143         .subbuf_start = subbuf_start_callback,
 144         .create_buf_file = create_buf_file_callback,
 145         .remove_buf_file = remove_buf_file_callback,
 146 };
 147 
 148 static void guc_move_to_next_buf(struct intel_guc_log *log)
 149 {
 150         /*
 151          * Make sure the updates made in the sub buffer are visible when
 152          * Consumer sees the following update to offset inside the sub buffer.
 153          */
 154         smp_wmb();
 155 
 156         /* All data has been written, so now move the offset of sub buffer. */
 157         relay_reserve(log->relay.channel, log->vma->obj->base.size);
 158 
 159         /* Switch to the next sub buffer */
 160         relay_flush(log->relay.channel);
 161 }
 162 
 163 static void *guc_get_write_buffer(struct intel_guc_log *log)
 164 {
 165         /*
 166          * Just get the base address of a new sub buffer and copy data into it
 167          * ourselves. NULL will be returned in no-overwrite mode, if all sub
 168          * buffers are full. Could have used the relay_write() to indirectly
 169          * copy the data, but that would have been bit convoluted, as we need to
 170          * write to only certain locations inside a sub buffer which cannot be
 171          * done without using relay_reserve() along with relay_write(). So its
 172          * better to use relay_reserve() alone.
 173          */
 174         return relay_reserve(log->relay.channel, 0);
 175 }
 176 
 177 static bool guc_check_log_buf_overflow(struct intel_guc_log *log,
 178                                        enum guc_log_buffer_type type,
 179                                        unsigned int full_cnt)
 180 {
 181         unsigned int prev_full_cnt = log->stats[type].sampled_overflow;
 182         bool overflow = false;
 183 
 184         if (full_cnt != prev_full_cnt) {
 185                 overflow = true;
 186 
 187                 log->stats[type].overflow = full_cnt;
 188                 log->stats[type].sampled_overflow += full_cnt - prev_full_cnt;
 189 
 190                 if (full_cnt < prev_full_cnt) {
 191                         /* buffer_full_cnt is a 4 bit counter */
 192                         log->stats[type].sampled_overflow += 16;
 193                 }
 194 
 195                 dev_notice_ratelimited(guc_to_gt(log_to_guc(log))->i915->drm.dev,
 196                                        "GuC log buffer overflow\n");
 197         }
 198 
 199         return overflow;
 200 }
 201 
 202 static unsigned int guc_get_log_buffer_size(enum guc_log_buffer_type type)
 203 {
 204         switch (type) {
 205         case GUC_ISR_LOG_BUFFER:
 206                 return ISR_BUFFER_SIZE;
 207         case GUC_DPC_LOG_BUFFER:
 208                 return DPC_BUFFER_SIZE;
 209         case GUC_CRASH_DUMP_LOG_BUFFER:
 210                 return CRASH_BUFFER_SIZE;
 211         default:
 212                 MISSING_CASE(type);
 213         }
 214 
 215         return 0;
 216 }
 217 
 218 static void guc_read_update_log_buffer(struct intel_guc_log *log)
 219 {
 220         unsigned int buffer_size, read_offset, write_offset, bytes_to_copy, full_cnt;
 221         struct guc_log_buffer_state *log_buf_state, *log_buf_snapshot_state;
 222         struct guc_log_buffer_state log_buf_state_local;
 223         enum guc_log_buffer_type type;
 224         void *src_data, *dst_data;
 225         bool new_overflow;
 226 
 227         mutex_lock(&log->relay.lock);
 228 
 229         if (WARN_ON(!intel_guc_log_relay_enabled(log)))
 230                 goto out_unlock;
 231 
 232         /* Get the pointer to shared GuC log buffer */
 233         log_buf_state = src_data = log->relay.buf_addr;
 234 
 235         /* Get the pointer to local buffer to store the logs */
 236         log_buf_snapshot_state = dst_data = guc_get_write_buffer(log);
 237 
 238         if (unlikely(!log_buf_snapshot_state)) {
 239                 /*
 240                  * Used rate limited to avoid deluge of messages, logs might be
 241                  * getting consumed by User at a slow rate.
 242                  */
 243                 DRM_ERROR_RATELIMITED("no sub-buffer to capture logs\n");
 244                 log->relay.full_count++;
 245 
 246                 goto out_unlock;
 247         }
 248 
 249         /* Actual logs are present from the 2nd page */
 250         src_data += PAGE_SIZE;
 251         dst_data += PAGE_SIZE;
 252 
 253         for (type = GUC_ISR_LOG_BUFFER; type < GUC_MAX_LOG_BUFFER; type++) {
 254                 /*
 255                  * Make a copy of the state structure, inside GuC log buffer
 256                  * (which is uncached mapped), on the stack to avoid reading
 257                  * from it multiple times.
 258                  */
 259                 memcpy(&log_buf_state_local, log_buf_state,
 260                        sizeof(struct guc_log_buffer_state));
 261                 buffer_size = guc_get_log_buffer_size(type);
 262                 read_offset = log_buf_state_local.read_ptr;
 263                 write_offset = log_buf_state_local.sampled_write_ptr;
 264                 full_cnt = log_buf_state_local.buffer_full_cnt;
 265 
 266                 /* Bookkeeping stuff */
 267                 log->stats[type].flush += log_buf_state_local.flush_to_file;
 268                 new_overflow = guc_check_log_buf_overflow(log, type, full_cnt);
 269 
 270                 /* Update the state of shared log buffer */
 271                 log_buf_state->read_ptr = write_offset;
 272                 log_buf_state->flush_to_file = 0;
 273                 log_buf_state++;
 274 
 275                 /* First copy the state structure in snapshot buffer */
 276                 memcpy(log_buf_snapshot_state, &log_buf_state_local,
 277                        sizeof(struct guc_log_buffer_state));
 278 
 279                 /*
 280                  * The write pointer could have been updated by GuC firmware,
 281                  * after sending the flush interrupt to Host, for consistency
 282                  * set write pointer value to same value of sampled_write_ptr
 283                  * in the snapshot buffer.
 284                  */
 285                 log_buf_snapshot_state->write_ptr = write_offset;
 286                 log_buf_snapshot_state++;
 287 
 288                 /* Now copy the actual logs. */
 289                 if (unlikely(new_overflow)) {
 290                         /* copy the whole buffer in case of overflow */
 291                         read_offset = 0;
 292                         write_offset = buffer_size;
 293                 } else if (unlikely((read_offset > buffer_size) ||
 294                                     (write_offset > buffer_size))) {
 295                         DRM_ERROR("invalid log buffer state\n");
 296                         /* copy whole buffer as offsets are unreliable */
 297                         read_offset = 0;
 298                         write_offset = buffer_size;
 299                 }
 300 
 301                 /* Just copy the newly written data */
 302                 if (read_offset > write_offset) {
 303                         i915_memcpy_from_wc(dst_data, src_data, write_offset);
 304                         bytes_to_copy = buffer_size - read_offset;
 305                 } else {
 306                         bytes_to_copy = write_offset - read_offset;
 307                 }
 308                 i915_memcpy_from_wc(dst_data + read_offset,
 309                                     src_data + read_offset, bytes_to_copy);
 310 
 311                 src_data += buffer_size;
 312                 dst_data += buffer_size;
 313         }
 314 
 315         guc_move_to_next_buf(log);
 316 
 317 out_unlock:
 318         mutex_unlock(&log->relay.lock);
 319 }
 320 
 321 static void capture_logs_work(struct work_struct *work)
 322 {
 323         struct intel_guc_log *log =
 324                 container_of(work, struct intel_guc_log, relay.flush_work);
 325 
 326         guc_log_capture_logs(log);
 327 }
 328 
 329 static int guc_log_map(struct intel_guc_log *log)
 330 {
 331         void *vaddr;
 332 
 333         lockdep_assert_held(&log->relay.lock);
 334 
 335         if (!log->vma)
 336                 return -ENODEV;
 337 
 338         /*
 339          * Create a WC (Uncached for read) vmalloc mapping of log
 340          * buffer pages, so that we can directly get the data
 341          * (up-to-date) from memory.
 342          */
 343         vaddr = i915_gem_object_pin_map(log->vma->obj, I915_MAP_WC);
 344         if (IS_ERR(vaddr))
 345                 return PTR_ERR(vaddr);
 346 
 347         log->relay.buf_addr = vaddr;
 348 
 349         return 0;
 350 }
 351 
 352 static void guc_log_unmap(struct intel_guc_log *log)
 353 {
 354         lockdep_assert_held(&log->relay.lock);
 355 
 356         i915_gem_object_unpin_map(log->vma->obj);
 357         log->relay.buf_addr = NULL;
 358 }
 359 
 360 void intel_guc_log_init_early(struct intel_guc_log *log)
 361 {
 362         mutex_init(&log->relay.lock);
 363         INIT_WORK(&log->relay.flush_work, capture_logs_work);
 364 }
 365 
 366 static int guc_log_relay_create(struct intel_guc_log *log)
 367 {
 368         struct intel_guc *guc = log_to_guc(log);
 369         struct drm_i915_private *dev_priv = guc_to_gt(guc)->i915;
 370         struct rchan *guc_log_relay_chan;
 371         size_t n_subbufs, subbuf_size;
 372         int ret;
 373 
 374         lockdep_assert_held(&log->relay.lock);
 375         GEM_BUG_ON(!log->vma);
 376 
 377          /* Keep the size of sub buffers same as shared log buffer */
 378         subbuf_size = log->vma->size;
 379 
 380         /*
 381          * Store up to 8 snapshots, which is large enough to buffer sufficient
 382          * boot time logs and provides enough leeway to User, in terms of
 383          * latency, for consuming the logs from relay. Also doesn't take
 384          * up too much memory.
 385          */
 386         n_subbufs = 8;
 387 
 388         guc_log_relay_chan = relay_open("guc_log",
 389                                         dev_priv->drm.primary->debugfs_root,
 390                                         subbuf_size, n_subbufs,
 391                                         &relay_callbacks, dev_priv);
 392         if (!guc_log_relay_chan) {
 393                 DRM_ERROR("Couldn't create relay chan for GuC logging\n");
 394 
 395                 ret = -ENOMEM;
 396                 return ret;
 397         }
 398 
 399         GEM_BUG_ON(guc_log_relay_chan->subbuf_size < subbuf_size);
 400         log->relay.channel = guc_log_relay_chan;
 401 
 402         return 0;
 403 }
 404 
 405 static void guc_log_relay_destroy(struct intel_guc_log *log)
 406 {
 407         lockdep_assert_held(&log->relay.lock);
 408 
 409         relay_close(log->relay.channel);
 410         log->relay.channel = NULL;
 411 }
 412 
 413 static void guc_log_capture_logs(struct intel_guc_log *log)
 414 {
 415         struct intel_guc *guc = log_to_guc(log);
 416         struct drm_i915_private *dev_priv = guc_to_gt(guc)->i915;
 417         intel_wakeref_t wakeref;
 418 
 419         guc_read_update_log_buffer(log);
 420 
 421         /*
 422          * Generally device is expected to be active only at this
 423          * time, so get/put should be really quick.
 424          */
 425         with_intel_runtime_pm(&dev_priv->runtime_pm, wakeref)
 426                 guc_action_flush_log_complete(guc);
 427 }
 428 
 429 static u32 __get_default_log_level(struct intel_guc_log *log)
 430 {
 431         /* A negative value means "use platform/config default" */
 432         if (i915_modparams.guc_log_level < 0) {
 433                 return (IS_ENABLED(CONFIG_DRM_I915_DEBUG) ||
 434                         IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)) ?
 435                         GUC_LOG_LEVEL_MAX : GUC_LOG_LEVEL_NON_VERBOSE;
 436         }
 437 
 438         if (i915_modparams.guc_log_level > GUC_LOG_LEVEL_MAX) {
 439                 DRM_WARN("Incompatible option detected: %s=%d, %s!\n",
 440                          "guc_log_level", i915_modparams.guc_log_level,
 441                          "verbosity too high");
 442                 return (IS_ENABLED(CONFIG_DRM_I915_DEBUG) ||
 443                         IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)) ?
 444                         GUC_LOG_LEVEL_MAX : GUC_LOG_LEVEL_DISABLED;
 445         }
 446 
 447         GEM_BUG_ON(i915_modparams.guc_log_level < GUC_LOG_LEVEL_DISABLED);
 448         GEM_BUG_ON(i915_modparams.guc_log_level > GUC_LOG_LEVEL_MAX);
 449         return i915_modparams.guc_log_level;
 450 }
 451 
 452 int intel_guc_log_create(struct intel_guc_log *log)
 453 {
 454         struct intel_guc *guc = log_to_guc(log);
 455         struct i915_vma *vma;
 456         u32 guc_log_size;
 457         int ret;
 458 
 459         GEM_BUG_ON(log->vma);
 460 
 461         /*
 462          *  GuC Log buffer Layout
 463          *
 464          *  +===============================+ 00B
 465          *  |    Crash dump state header    |
 466          *  +-------------------------------+ 32B
 467          *  |       DPC state header        |
 468          *  +-------------------------------+ 64B
 469          *  |       ISR state header        |
 470          *  +-------------------------------+ 96B
 471          *  |                               |
 472          *  +===============================+ PAGE_SIZE (4KB)
 473          *  |        Crash Dump logs        |
 474          *  +===============================+ + CRASH_SIZE
 475          *  |           DPC logs            |
 476          *  +===============================+ + DPC_SIZE
 477          *  |           ISR logs            |
 478          *  +===============================+ + ISR_SIZE
 479          */
 480         guc_log_size = PAGE_SIZE + CRASH_BUFFER_SIZE + DPC_BUFFER_SIZE +
 481                         ISR_BUFFER_SIZE;
 482 
 483         vma = intel_guc_allocate_vma(guc, guc_log_size);
 484         if (IS_ERR(vma)) {
 485                 ret = PTR_ERR(vma);
 486                 goto err;
 487         }
 488 
 489         log->vma = vma;
 490 
 491         log->level = __get_default_log_level(log);
 492         DRM_DEBUG_DRIVER("guc_log_level=%d (%s, verbose:%s, verbosity:%d)\n",
 493                          log->level, enableddisabled(log->level),
 494                          yesno(GUC_LOG_LEVEL_IS_VERBOSE(log->level)),
 495                          GUC_LOG_LEVEL_TO_VERBOSITY(log->level));
 496 
 497         return 0;
 498 
 499 err:
 500         DRM_ERROR("Failed to allocate GuC log buffer. %d\n", ret);
 501         return ret;
 502 }
 503 
 504 void intel_guc_log_destroy(struct intel_guc_log *log)
 505 {
 506         i915_vma_unpin_and_release(&log->vma, 0);
 507 }
 508 
 509 int intel_guc_log_set_level(struct intel_guc_log *log, u32 level)
 510 {
 511         struct intel_guc *guc = log_to_guc(log);
 512         struct drm_i915_private *dev_priv = guc_to_gt(guc)->i915;
 513         intel_wakeref_t wakeref;
 514         int ret = 0;
 515 
 516         BUILD_BUG_ON(GUC_LOG_VERBOSITY_MIN != 0);
 517         GEM_BUG_ON(!log->vma);
 518 
 519         /*
 520          * GuC is recognizing log levels starting from 0 to max, we're using 0
 521          * as indication that logging should be disabled.
 522          */
 523         if (level < GUC_LOG_LEVEL_DISABLED || level > GUC_LOG_LEVEL_MAX)
 524                 return -EINVAL;
 525 
 526         mutex_lock(&dev_priv->drm.struct_mutex);
 527 
 528         if (log->level == level)
 529                 goto out_unlock;
 530 
 531         with_intel_runtime_pm(&dev_priv->runtime_pm, wakeref)
 532                 ret = guc_action_control_log(guc,
 533                                              GUC_LOG_LEVEL_IS_VERBOSE(level),
 534                                              GUC_LOG_LEVEL_IS_ENABLED(level),
 535                                              GUC_LOG_LEVEL_TO_VERBOSITY(level));
 536         if (ret) {
 537                 DRM_DEBUG_DRIVER("guc_log_control action failed %d\n", ret);
 538                 goto out_unlock;
 539         }
 540 
 541         log->level = level;
 542 
 543 out_unlock:
 544         mutex_unlock(&dev_priv->drm.struct_mutex);
 545 
 546         return ret;
 547 }
 548 
 549 bool intel_guc_log_relay_enabled(const struct intel_guc_log *log)
 550 {
 551         return log->relay.buf_addr;
 552 }
 553 
 554 int intel_guc_log_relay_open(struct intel_guc_log *log)
 555 {
 556         int ret;
 557 
 558         if (!log->vma)
 559                 return -ENODEV;
 560 
 561         mutex_lock(&log->relay.lock);
 562 
 563         if (intel_guc_log_relay_enabled(log)) {
 564                 ret = -EEXIST;
 565                 goto out_unlock;
 566         }
 567 
 568         /*
 569          * We require SSE 4.1 for fast reads from the GuC log buffer and
 570          * it should be present on the chipsets supporting GuC based
 571          * submisssions.
 572          */
 573         if (!i915_has_memcpy_from_wc()) {
 574                 ret = -ENXIO;
 575                 goto out_unlock;
 576         }
 577 
 578         ret = guc_log_relay_create(log);
 579         if (ret)
 580                 goto out_unlock;
 581 
 582         ret = guc_log_map(log);
 583         if (ret)
 584                 goto out_relay;
 585 
 586         mutex_unlock(&log->relay.lock);
 587 
 588         guc_log_enable_flush_events(log);
 589 
 590         /*
 591          * When GuC is logging without us relaying to userspace, we're ignoring
 592          * the flush notification. This means that we need to unconditionally
 593          * flush on relay enabling, since GuC only notifies us once.
 594          */
 595         queue_work(system_highpri_wq, &log->relay.flush_work);
 596 
 597         return 0;
 598 
 599 out_relay:
 600         guc_log_relay_destroy(log);
 601 out_unlock:
 602         mutex_unlock(&log->relay.lock);
 603 
 604         return ret;
 605 }
 606 
 607 void intel_guc_log_relay_flush(struct intel_guc_log *log)
 608 {
 609         struct intel_guc *guc = log_to_guc(log);
 610         struct drm_i915_private *i915 = guc_to_gt(guc)->i915;
 611         intel_wakeref_t wakeref;
 612 
 613         /*
 614          * Before initiating the forceful flush, wait for any pending/ongoing
 615          * flush to complete otherwise forceful flush may not actually happen.
 616          */
 617         flush_work(&log->relay.flush_work);
 618 
 619         with_intel_runtime_pm(&i915->runtime_pm, wakeref)
 620                 guc_action_flush_log(guc);
 621 
 622         /* GuC would have updated log buffer by now, so capture it */
 623         guc_log_capture_logs(log);
 624 }
 625 
 626 void intel_guc_log_relay_close(struct intel_guc_log *log)
 627 {
 628         struct intel_guc *guc = log_to_guc(log);
 629         struct drm_i915_private *i915 = guc_to_gt(guc)->i915;
 630 
 631         guc_log_disable_flush_events(log);
 632         intel_synchronize_irq(i915);
 633 
 634         flush_work(&log->relay.flush_work);
 635 
 636         mutex_lock(&log->relay.lock);
 637         GEM_BUG_ON(!intel_guc_log_relay_enabled(log));
 638         guc_log_unmap(log);
 639         guc_log_relay_destroy(log);
 640         mutex_unlock(&log->relay.lock);
 641 }
 642 
 643 void intel_guc_log_handle_flush_event(struct intel_guc_log *log)
 644 {
 645         queue_work(system_highpri_wq, &log->relay.flush_work);
 646 }