[Intel-gfx] [PATCH v8 00/20] Gen8+ engine-reset

[Michel Thierry]

These patches add the reset-engine feature from Gen8. This is also
referred to as Timeout detection and recovery (TDR). This complements to
the full gpu reset feature available in i915 but it only allows to reset a
particular engine instead of all engines thus providing a light weight
engine reset and recovery mechanism.

Thanks to recent changes merged, this implementation is now not only for
execlists, but for GuC based submission too; it is still limited from
Gen8 onwards. I have also included the changes for watchdog timeout
detection. The GuC related patches are functional, but can be seen as RFC.

Timeout detection relies on the existing hangcheck, which remains the same;
main changes are to the recovery mechanism. Once we detect a hang on a
particular engine we identify the request that caused the hang, skip the
request and adjust head pointers to allow the execution to proceed
normally. After some cleanup, submissions are restarted to process
remaining work queued to that engine.

If engine reset fails to recover engine correctly then we fallback to full
gpu reset.

We can argue about the effectiveness of reset-engine vs full reset when
more than one ring is hung, but the benefits of just resetting one engine
are reduced when the driver has to do it multiple times.

v2: ELSP queue request tracking and reset path changes to handle incomplete
requests during reset. Thanks to Chris Wilson for providing these patches.

v3: Let the waiter keep handling the full gpu reset if it already has the
lock; point out that GuC submission needs a different method to restart
workloads after the engine reset completes.

v4: Handle reset as 2 level resets, by first going to engine only and fall
backing to full/chip reset as needed, i.e. reset_engine will need the
struct_mutex.

v5: Rebased after reset flag split in 2, add GuC support, include watchdog
detection patches, addressing comments from prev RFC.

v6: Mutex-less reset engine. Updates in watchdog abi and guc whitelist &
register-restore fixes (including an old patch from Daniele).

v7: Removed leftovers from v5; review comments; ability to cancel the reset
if there's no active request.

v8: Moved patch looking for active request at the beginning of these series;
drop patch to request the engine's reset readinnes earlier since this is
done during the reset flow too; warn if hw fails to acknowledge reset
_readiness_.

Daniele Ceraolo Spurio (1):
  drm/i915/guc: fix mmio whitelist mmio_start offset and add reminder

Michel Thierry (19):
  drm/i915: Look for active requests earlier in the reset path
  drm/i915: Update i915.reset to handle engine resets
  drm/i915: Modify error handler for per engine hang recovery
  drm/i915: Add support for per engine reset recovery
  drm/i915: Add engine reset count to error state
  drm/i915: Export per-engine reset count info to debugfs
  drm/i915: Carry on with reset even if hw engine is not ready
  drm/i915: Enable Engine reset and recovery support
  drm/i915: Add engine reset count in get-reset-stats ioctl
  drm/i915/selftests: reset engine self tests
  drm/i915/guc: Provide register list to be saved/restored during engine
    reset
  drm/i915/guc: Rename the function that resets the GuC
  drm/i915/guc: Add support for reset engine using GuC commands
  drm/i915: Watchdog timeout: Pass GuC shared data structure during
    param load
  drm/i915: Watchdog timeout: IRQ handler for gen8+
  drm/i915: Watchdog timeout: Ringbuffer command emission for gen8+
  drm/i915: Watchdog timeout: DRM kernel interface to set the timeout
  drm/i915: Watchdog timeout: Include threshold value in error state
  drm/i915: Watchdog timeout: Export media reset count from GuC to
    debugfs

 drivers/gpu/drm/i915/i915_debugfs.c              |  43 +++++++
 drivers/gpu/drm/i915/i915_drv.c                  |  74 +++++++++++
 drivers/gpu/drm/i915/i915_drv.h                  |  90 ++++++++++++-
 drivers/gpu/drm/i915/i915_gem.c                  | 104 +++++++++------
 drivers/gpu/drm/i915/i915_gem_context.c          | 109 +++++++++++++++-
 drivers/gpu/drm/i915/i915_gem_context.h          |   4 +
 drivers/gpu/drm/i915/i915_gpu_error.c            |  15 ++-
 drivers/gpu/drm/i915/i915_guc_submission.c       | 138 ++++++++++++++++++--
 drivers/gpu/drm/i915/i915_irq.c                  |  36 +++++-
 drivers/gpu/drm/i915/i915_params.c               |   6 +-
 drivers/gpu/drm/i915/i915_params.h               |   2 +-
 drivers/gpu/drm/i915/i915_pci.c                  |   5 +-
 drivers/gpu/drm/i915/i915_reg.h                  |   6 +
 drivers/gpu/drm/i915/intel_engine_cs.c           |  65 +++++++---
 drivers/gpu/drm/i915/intel_guc_fwif.h            |  27 +++-
 drivers/gpu/drm/i915/intel_guc_loader.c          |  11 ++
 drivers/gpu/drm/i915/intel_hangcheck.c           |  13 +-
 drivers/gpu/drm/i915/intel_lrc.c                 | 155 ++++++++++++++++++++++-
 drivers/gpu/drm/i915/intel_ringbuffer.h          |   9 ++
 drivers/gpu/drm/i915/intel_uc.c                  |   4 +-
 drivers/gpu/drm/i915/intel_uc.h                  |   3 +
 drivers/gpu/drm/i915/intel_uncore.c              |  16 ++-
 drivers/gpu/drm/i915/selftests/intel_hangcheck.c | 149 ++++++++++++++++++++++
 include/uapi/drm/i915_drm.h                      |   7 +-
 24 files changed, 986 insertions(+), 105 deletions(-)

-- 
2.11.0