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drm/xe: only resume exec queues that were actually suspended

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A consumer-issued suspend() can fail (e.g. the queue is killed, banned
or wedged), leaving the queue un-suspended. The consumer must then not
issue the matching resume(): resuming a queue that was never suspended
is incorrect.

Add an lr.suspended flag to struct xe_exec_queue that records whether a
consumer suspend() succeeded and a matching resume() is still owed. Set
it on a successful suspend() in the preempt-fence path, clear it on
resume(), and only resume queues that have it set.

In resume_and_reinstall_preempt_fences() also skip queues that have
since been reset/killed/banned/wedged: such a queue's suspend may not
have completed (suspend_pending can still be set, e.g. a preempt fence
signalled with -ENOENT without waiting), so resuming it would trip the
!suspend_pending assert in the backend. Leave it marked suspended and
let teardown resolve its state.

A queue is only ever suspended by a single consumer at a time
(preempt-fence mode and hw engine group fault mode are mutually
exclusive), so a single flag is sufficient.

Assisted-by: Github-Copilot:Claude-opus-4.8
Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20260713202317.2187787-9-niranjana.vishwanathapura@intel.com
This commit is contained in:
Niranjana Vishwanathapura
2026-07-13 13:23:16 -07:00
parent 068388c0cd
commit 65f40fa502
3 changed files with 36 additions and 1 deletions
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12
drivers/gpu/drm/xe/xe_exec_queue_types.h
View File

@@ -200,6 +200,18 @@ struct xe_exec_queue {
u32 seqno;
/** @lr.link: link into VM's list of exec queues */
struct list_head link;
/**
* @lr.suspended: Tracks whether the consumer-issued suspend()
* succeeded and a matching resume() is still owed. suspend() can
* fail (e.g. killed/banned/wedged), leaving the queue
* un-suspended, so consumers must only resume() queues that were
* actually suspended. Set by the suspend caller on success and
* cleared by the resume caller. A queue is only ever suspended by
* a single consumer at a time (preempt-fence mode and hw engine
* group fault mode are mutually exclusive), so a single flag is
* sufficient.
*/
bool suspended;
} lr;
#define XE_EXEC_QUEUE_TLB_INVAL_PRIMARY_GT 0

7
drivers/gpu/drm/xe/xe_preempt_fence.c
View File

@@ -74,6 +74,13 @@ static bool preempt_fence_enable_signaling(struct dma_fence *fence)
struct xe_exec_queue *q = pfence->q;
pfence->error = q->ops->suspend(q);
/*
* Record a successful suspend so the rebind worker only resumes queues
* that were actually suspended; a failed suspend() leaves the queue
* un-suspended and must not be paired with a resume().
*/
if (!pfence->error)
WRITE_ONCE(q->lr.suspended, true);
queue_work(q->vm->xe->preempt_fence_wq, &pfence->preempt_work);
return true;
}

18
drivers/gpu/drm/xe/xe_vm.c
View File

@@ -206,7 +206,23 @@ static void resume_and_reinstall_preempt_fences(struct xe_vm *vm,
xe_vm_assert_held(vm);
list_for_each_entry(q, &vm->preempt.exec_queues, lr.link) {
q->ops->resume(q);
/*
* Only resume queues whose suspend() actually succeeded. A
* failed suspend() (e.g. killed/banned/wedged) leaves the queue
* un-suspended, so it must not be resumed.
*
* Also skip queues that have since been reset/killed/banned/
* wedged: their suspend may not have completed (suspend_pending
* can still be set, e.g. a preempt fence signalled with -ENOENT
* without waiting), so resuming would trip the !suspend_pending
* assert in the backend. Such queues are being torn down anyway,
* so leave them marked suspended and let teardown resolve their
* state.
*/
if (READ_ONCE(q->lr.suspended) && !q->ops->reset_status(q)) {
WRITE_ONCE(q->lr.suspended, false);
q->ops->resume(q);
}
drm_gpuvm_resv_add_fence(&vm->gpuvm, exec, q->lr.pfence,
DMA_RESV_USAGE_BOOKKEEP, DMA_RESV_USAGE_BOOKKEEP);