+the PVR devs On Mon, 31 Jul 2023 01:00:59 +0000 Matthew Brost <matthew.brost@xxxxxxxxx> wrote: > On Thu, May 04, 2023 at 01:23:05AM -0400, Luben Tuikov wrote: > > On 2023-04-03 20:22, Matthew Brost wrote: > > > If the TDR is set to a value, it can fire before a job is submitted in > > > drm_sched_main. The job should be always be submitted before the TDR > > > fires, fix this ordering. > > > > > > Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx> > > > --- > > > drivers/gpu/drm/scheduler/sched_main.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c > > > index 6ae710017024..4eac02d212c1 100644 > > > --- a/drivers/gpu/drm/scheduler/sched_main.c > > > +++ b/drivers/gpu/drm/scheduler/sched_main.c > > > @@ -1150,10 +1150,10 @@ static void drm_sched_main(struct work_struct *w) > > > s_fence = sched_job->s_fence; > > > > > > atomic_inc(&sched->hw_rq_count); > > > - drm_sched_job_begin(sched_job); > > > > > > trace_drm_run_job(sched_job, entity); > > > fence = sched->ops->run_job(sched_job); > > > + drm_sched_job_begin(sched_job); > > > complete_all(&entity->entity_idle); > > > drm_sched_fence_scheduled(s_fence); > > > > > > > Not sure if this is correct. In drm_sched_job_begin() we add the job to the "pending_list" > > (meaning it is pending execution in the hardware) and we also start a timeout timer. Both > > of those should be started before the job is given to the hardware. > > > > The correct solution is probably add to pending list before run_job() > and kick TDR after run_job(). This would make the PVR driver simpler too. Right now, the driver iterates over the pending job list to signal jobs done_fences, but there's a race between the interrupt handler (that's iterating over this list to signal fences) and the drm_sched logic (that's inserting the job in the pending_list after run_job() returns). The race is taken care of with an addition field that's pointing to the last submitted job [1], but if we can get rid of that logic, that's for the best. [1]https://gitlab.freedesktop.org/frankbinns/powervr/-/blob/powervr-next/drivers/gpu/drm/imagination/pvr_queue.h#L119
