Re: [PATCH] drm/panthor: always set fence errors on CS_FAULT

[Boris Brezillon]

On Wed, 18 Jun 2025 07:55:49 -0700
Chia-I Wu <olvaffe@xxxxxxxxx> wrote:

> It is unclear why fence errors were set only for CS_INHERIT_FAULT.
> Downstream driver also does not treat CS_INHERIT_FAULT specially.
> Remove the check.
> 
> Signed-off-by: Chia-I Wu <olvaffe@xxxxxxxxx>
> ---
>  drivers/gpu/drm/panthor/panthor_sched.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
> index a2248f692a030..1a3b1c49f7d7b 100644
> --- a/drivers/gpu/drm/panthor/panthor_sched.c
> +++ b/drivers/gpu/drm/panthor/panthor_sched.c
> @@ -1399,7 +1399,7 @@ cs_slot_process_fault_event_locked(struct panthor_device *ptdev,
>  	fault = cs_iface->output->fault;
>  	info = cs_iface->output->fault_info;
>  
> -	if (queue && CS_EXCEPTION_TYPE(fault) == DRM_PANTHOR_EXCEPTION_CS_INHERIT_FAULT) {
> +	if (queue) {
>  		u64 cs_extract = queue->iface.output->extract;
>  		struct panthor_job *job;
>  

Now that I look at the code, I think we should record the error when
the ERROR_BARRIER is executed instead of flagging all in-flight jobs as
faulty. One option would be to re-use the profiling buffer by adding an
error field to panthor_job_profiling_data, but we're going to lose 4
bytes per slot because of the 64-bit alignment we want for timestamps,
so maybe just create a separate buffers with N entries of:

struct panthor_job_status {
   u32 error;
};