Re: [PATCH 2/4] drm/sched: Add callback and enable signaling on debug

[Christian König]

Am 05.09.22 um 12:56 schrieb Arvind Yadav:
> Here's on debug adding an enable_signaling callback for finished
> fences and enabling software signaling for finished fence.
>
> Signed-off-by: Arvind Yadav <Arvind.Yadav@xxxxxxx>
> ---
>   drivers/gpu/drm/scheduler/sched_fence.c | 12 ++++++++++++
>   drivers/gpu/drm/scheduler/sched_main.c  |  4 +++-
>   2 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/scheduler/sched_fence.c b/drivers/gpu/drm/scheduler/sched_fence.c
> index 7fd869520ef2..ebd26cdb79a0 100644
> --- a/drivers/gpu/drm/scheduler/sched_fence.c
> +++ b/drivers/gpu/drm/scheduler/sched_fence.c
> @@ -122,16 +122,28 @@ static void drm_sched_fence_release_finished(struct dma_fence *f)
>   
>   	dma_fence_put(&fence->scheduled);
>   }
> +#ifdef CONFIG_DEBUG_FS
> +static bool drm_sched_enable_signaling(struct dma_fence *f)
> +{
> +	return true;
> +}
> +#endif
>   
>   static const struct dma_fence_ops drm_sched_fence_ops_scheduled = {
>   	.get_driver_name = drm_sched_fence_get_driver_name,
>   	.get_timeline_name = drm_sched_fence_get_timeline_name,
> +#ifdef CONFIG_DEBUG_FS
> +	.enable_signaling = drm_sched_enable_signaling,
> +#endif
>   	.release = drm_sched_fence_release_scheduled,
>   };
>   
>   static const struct dma_fence_ops drm_sched_fence_ops_finished = {
>   	.get_driver_name = drm_sched_fence_get_driver_name,
>   	.get_timeline_name = drm_sched_fence_get_timeline_name,
> +#ifdef CONFIG_DEBUG_FS
> +	.enable_signaling = drm_sched_enable_signaling,
> +#endif

Adding the callback should not be necessary.

>   	.release = drm_sched_fence_release_finished,
>   };
>   
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> index e0ab14e0fb6b..140e3d8646e2 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -961,7 +961,9 @@ static int drm_sched_main(void *param)
>   			s_fence->parent = dma_fence_get(fence);
>   			/* Drop for original kref_init of the fence */
>   			dma_fence_put(fence);

Uff, not related to your patch but that looks wrong to me. The reference 
can only be dropped after the call to dma_fence_add_callback().

> -
> +#ifdef CONFIG_DEBUG_FS
> +			dma_fence_enable_sw_signaling(&s_fence->finished);
> +#endif

This should always be called, independent of the config options set.

Christian.

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