[PATCH v10 0/5] drm/amdgpu: Add WAIT_EVENT ioctl for render-node events

This series introduces a render-node WAIT_EVENT ioctl for retrieving
AMDGPU event records and their associated metadata.

WAIT_EVENT complements the EVENTFD notification interface rather than
replacing it. EVENTFD provides lightweight readiness notifications,
while WAIT_EVENT allows userspace to retrieve the corresponding event
type, queue identity, and event-specific metadata.

This series builds on the render-node EVENTFD infrastructure introduced
in:

  https://patchwork.freedesktop.org/series/164618/

It also depends on the EVENTFD producer series:

  drm/amdgpu: Wire GPU events into EVENTFD notifications
  https://patchwork.freedesktop.org/series/168402/

The WAIT_EVENT manager is maintained per drm_file. Queue-scoped requests
resolve the userspace queue_id to the corresponding user queue at the
ioctl boundary. Pending records are matched internally using queue
pointer equality, while queue_id remains a userspace identifier used at
the UAPI boundary and returned in event metadata.

The initial producer set records USERQ_EOP and QUEUE_RESET events by
reusing the existing queue-resolution paths:

  - USERQ_EOP records are generated from
    amdgpu_userq_process_fence_irq(), reusing the existing
    doorbell-to-queue lookup.

  - QUEUE_RESET records are generated from
    amdgpu_userq_handle_hung_queue(), where successful queue reset
    handling already converges.

This avoids additional queue lookups, queue scans, or changes to the
existing interrupt handling paths.

MEMORY_EXCEPTION and SCRATCH WAIT_EVENT producers are intentionally not
included in this series. MEMORY_EXCEPTION depends on separate PASID to
file-private lookup work, while SCRATCH follows a different notification
path and will be addressed separately.

Changes since v9
================

- Replace the relative timeout with an absolute CLOCK_MONOTONIC
  deadline, as suggested by Christian.

- Recompute the remaining timeout after every wakeup so interrupted or
  spurious wakeups continue to honor the original userspace deadline.

- Add kerneldoc for the WAIT_EVENT manager, timeout conversion,
  matching helpers, producer helpers, and teardown paths.

- Clarify the lifetime of the per-file WAIT_EVENT manager. The USERQ
  manager is torn down before the embedded WAIT_EVENT manager is
  finalized, so queues are removed from producer lookup paths before the
  manager can go out of scope.

- Keep queue pointers as the internal routing and matching key for
  queue-scoped events.

- Populate queue_id only at the WAIT_EVENT ioctl boundary after a record
  is matched, keeping queue_id as a userspace identifier rather than an
  internal routing key.

- Simplify queue reference cleanup by relying on
  amdgpu_userq_put() to handle NULL pointers.

- Improve documentation describing manager state, event matching, and
  teardown ordering.

Srinivasan Shanmugam (5):
  drm/amdgpu/uapi: Add WAIT_EVENT ioctl and metadata structures
  drm/amdgpu: Add wait-event manager and per-file lifetime plumbing
  drm/amdgpu: Remove queue-scoped WAIT_EVENT records on queue teardown
  drm/amdgpu: Record USERQ_EOP WAIT_EVENT notifications
  drm/amdgpu: Record QUEUE_RESET WAIT_EVENT notifications

 drivers/gpu/drm/amd/amdgpu/Makefile           |   2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu.h           |   5 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c       |   1 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c       |   5 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c     |  33 ++
 drivers/gpu/drm/amd/amdgpu/amdgpu_userq.h     |   2 +
 .../gpu/drm/amd/amdgpu/amdgpu_wait_event.c    | 508 ++++++++++++++++++
 .../gpu/drm/amd/amdgpu/amdgpu_wait_event.h    | 101 ++++
 include/uapi/drm/amdgpu_drm.h                 | 115 ++++
 9 files changed, 769 insertions(+), 3 deletions(-)
 create mode 100644 drivers/gpu/drm/amd/amdgpu/amdgpu_wait_event.c
 create mode 100644 drivers/gpu/drm/amd/amdgpu/amdgpu_wait_event.h

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2.34.1