[PATCH 1/2] drm/sched: Set error to s_fence if HW job submission failed.

[Koenig, Christian]

Am 25.10.19 um 16:57 schrieb Grodzovsky, Andrey:
> On 10/25/19 4:44 AM, Christian König wrote:
>> Am 24.10.19 um 21:57 schrieb Andrey Grodzovsky:
>>> Problem:
>>> When run_job fails and HW fence returned is NULL we still signal
>>> the s_fence to avoid hangs but the user has no way of knowing if
>>> the actual HW job was ran and finished.
>>>
>>> Fix:
>>> Allow .run_job implementations to return ERR_PTR in the fence pointer
>>> returned and then set this error for s_fence->finished fence so whoever
>>> wait on this fence can inspect the signaled fence for an error.
>>>
>>> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
>>> ---
>>>    drivers/gpu/drm/scheduler/sched_main.c | 19 ++++++++++++++++---
>>>    1 file changed, 16 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/scheduler/sched_main.c
>>> b/drivers/gpu/drm/scheduler/sched_main.c
>>> index 9a0ee74..f39b97e 100644
>>> --- a/drivers/gpu/drm/scheduler/sched_main.c
>>> +++ b/drivers/gpu/drm/scheduler/sched_main.c
>>> @@ -479,6 +479,7 @@ void drm_sched_resubmit_jobs(struct
>>> drm_gpu_scheduler *sched)
>>>        struct drm_sched_job *s_job, *tmp;
>>>        uint64_t guilty_context;
>>>        bool found_guilty = false;
>>> +    struct dma_fence *fence;
>>>          list_for_each_entry_safe(s_job, tmp,
>>> &sched->ring_mirror_list, node) {
>>>            struct drm_sched_fence *s_fence = s_job->s_fence;
>>> @@ -492,7 +493,16 @@ void drm_sched_resubmit_jobs(struct
>>> drm_gpu_scheduler *sched)
>>>                dma_fence_set_error(&s_fence->finished, -ECANCELED);
>>>              dma_fence_put(s_job->s_fence->parent);
>>> -        s_job->s_fence->parent = sched->ops->run_job(s_job);
>>> +        fence = sched->ops->run_job(s_job);
>>> +
>>> +        if (IS_ERR_OR_NULL(fence)) {
>>> +            s_job->s_fence->parent = NULL;
>>> +            dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
>>> +        } else {
>>> +            s_job->s_fence->parent = fence;
>>> +        }
>>> +
>>> +
>> Maybe time for a drm_sched_run_job() function which does that
>> handling? And why don't we need to install the callback here?
>
> What code do you want to put in drm_sched_run_job ?
>
> We reinstall the callback later in drm_sched_start,
> drm_sched_resubmit_jobs is conditional on whether the guilty fence did
> signal by this time or not and so the split of the logic into
> drm_sched_start and drm_sched_resubmit_jobs.

Ah, yes of course. In this case the patch is Reviewed-by: Christian 
König <christian.koenig at amd.com>.

Regards,
Christian.

>
> Andrey
>
>
>> Apart from that looks good to me,
>> Christian.
>>
>>>        }
>>>    }
>>>    EXPORT_SYMBOL(drm_sched_resubmit_jobs);
>>> @@ -720,7 +730,7 @@ static int drm_sched_main(void *param)
>>>            fence = sched->ops->run_job(sched_job);
>>>            drm_sched_fence_scheduled(s_fence);
>>>    -        if (fence) {
>>> +        if (!IS_ERR_OR_NULL(fence)) {
>>>                s_fence->parent = dma_fence_get(fence);
>>>                r = dma_fence_add_callback(fence, &sched_job->cb,
>>>                               drm_sched_process_job);
>>> @@ -730,8 +740,11 @@ static int drm_sched_main(void *param)
>>>                    DRM_ERROR("fence add callback failed (%d)\n",
>>>                          r);
>>>                dma_fence_put(fence);
>>> -        } else
>>> +        } else {
>>> +
>>> +            dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
>>>                drm_sched_process_job(NULL, &sched_job->cb);
>>> +        }
>>>              wake_up(&sched->job_scheduled);
>>>        }