Re: [PATCH v2 1/4] drm/sched: Enable signaling for finished fence

[Andrey Grodzovsky]

On 2022-09-06 02:34, Christian König wrote:
> Am 05.09.22 um 18:34 schrieb Arvind Yadav:
> > Here's enabling software signaling for finished fence.
> >
> > Signed-off-by: Arvind Yadav <Arvind.Yadav@xxxxxxx>
> > ---
> >
> > Changes in v1 :
> > 1- Addressing Christian's comment to remove CONFIG_DEBUG_FS check from
> > this patch.
> > 2- The version of this patch is also changed and previously
> > it was [PATCH 2/4]
> >
> > ---
> >   drivers/gpu/drm/scheduler/sched_main.c | 2 ++
> >   1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/scheduler/sched_main.c 
> > b/drivers/gpu/drm/scheduler/sched_main.c
> > index e0ab14e0fb6b..fe72de0e2911 100644
> > --- a/drivers/gpu/drm/scheduler/sched_main.c
> > +++ b/drivers/gpu/drm/scheduler/sched_main.c
> > @@ -962,6 +962,8 @@ static int drm_sched_main(void *param)
> >               /* Drop for original kref_init of the fence */
> >               dma_fence_put(fence);
> >   + dma_fence_enable_sw_signaling(&s_fence->finished);
>
> Ok, this makes it a lot clearer. Previously I though that we have some 
> bug in dma_fence_add_callback().
>
> This is essentially the wrong place to call this, the finished fence 
> should be enabled by the caller and not here.
>
> There is also another problem in dma_fence_enable_sw_signaling(), it 
> returns early when the fence is already signaled:
>
>         if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
>                 return;
>
> Please remove that one first.


Why we even need this explicit call if dma_fence_add_callback calls 
__dma_fence_enable_signaling anyway ?

Andrey


> Thanks,
> Christian.
>
>
> > +
> >               r = dma_fence_add_callback(fence, &sched_job->cb,
> >                              drm_sched_job_done_cb);
> >               if (r == -ENOENT)