On Sun, Jun 22, 2025 at 11:32 PM Boris Brezillon
<boris.brezil...@collabora.com> wrote:
>
> On Wed, 18 Jun 2025 07:55:49 -0700
> Chia-I Wu <olva...@gmail.com> 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 <olva...@gmail.com>
> > ---
> > 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;
> };
The current error path uses cs_extract to mark exactly the offending
job faulty. Innocent in-flight jobs do not seem to be affected.
I looked into emitting LOAD/STORE after SYNC_ADD64 to copy the error
to panthor_job_status. Other than the extra instrs and storage,
because group_sync_upd_work can be called before LOAD/STORE, it will
need to check both panthor_job_status and panthor_syncobj_64b. That
will be a bit ugly as well.
