[PATCH] drm/sched: Call drm_sched_fence_set_parent() from drm_sched_fence_scheduled()

[Christian König]

Am 13.06.23 um 11:46 schrieb Boris Brezillon:
> On Tue, 13 Jun 2023 11:44:24 +0200
> Boris Brezillon <boris.brezillon at collabora.com> wrote:
>
>> Drivers that can delegate waits to the firmware/GPU pass the scheduled
>> fence to drm_sched_job_add_dependency(), and issue wait commands to
>> the firmware/GPU at job submission time. For this to be possible, they
>> need all their 'native' dependencies to have a valid parent since this
>> is where the actual HW fence information are encoded.
>>
>> In drm_sched_main(), we currently call drm_sched_fence_set_parent()
>> after drm_sched_fence_set_parent(), leaving a short period of time
> after drm_sched_fence_scheduled(), ...

I was just about to complain, but yeah sounds like the right idea to me.

Just let me review the patch in more detail.

Christian.

>
>> during which the job depending on this fence can be submitted.
>>
>> Since setting parent and signaling the fence are two things that are
>> kinda related (you can't have a parent if the job hasn't been scheduled),
>> it probably makes sense to pass the parent fence to
>> drm_sched_fence_scheduled() and let it call drm_sched_fence_set_parent()
>> before it signals the scheduled fence.