Re: [PATCH v5] drm/i915/pxp: Add drm_dbgs for critical PXP events.

["Teres Alexis, Alan Previn" <alan.previn.teres.alexis@xxxxxxxxx>]

On Fri, 2023-11-24 at 08:30 +0000, Tvrtko Ursulin wrote:
> On 22/11/2023 19:15, Alan Previn wrote:
alan:snip
alan: thanks for reviewing.
> >   	if (iir & GEN12_DISPLAY_STATE_RESET_COMPLETE_INTERRUPT)
> > -		pxp->session_events |= PXP_TERMINATION_COMPLETE;
> > +		pxp->session_events |= PXP_TERMINATION_COMPLETE | PXP_EVENT_TYPE_IRQ;
> 
> This looked to be doing more than adding debug logs, but then no one is 
> actually consuming this new flag?!
alan: see below hunk, inside pxp_session_work the drm_dbg that was prints
the "events" that came from above. we need this debug message to uniquely
recognize that contexts pxp keys would get invalidated in response to
a KCR IRQ (as opposed to other known flows that are being reported by other
means like banning hanging contexts, or as part of suspend etc).
NOTE: pxp->session_events does get set in at lease one other path
outside the IRQ (which triggers teardown but not coming from KCR-hw)
This flag is solely for the debug message. Hope this works.

> 
> Regards,
> 
> Tvrtko
> 
> >   
> >   	if (pxp->session_events)
> >   		queue_work(system_unbound_wq, &pxp->session_work);
> > diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_session.c b/drivers/gpu/drm/i915/pxp/intel_pxp_session.c
> > index 0a3e66b0265e..091c86e03d1a 100644
> > --- a/drivers/gpu/drm/i915/pxp/intel_pxp_session.c
> > +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_session.c
> > @@ -137,8 +137,10 @@ void intel_pxp_terminate(struct intel_pxp *pxp, bool post_invalidation_needs_res
> >   static void pxp_terminate_complete(struct intel_pxp *pxp)
> >   {
> >   	/* Re-create the arb session after teardown handle complete */
> > -	if (fetch_and_zero(&pxp->hw_state_invalidated))
> > +	if (fetch_and_zero(&pxp->hw_state_invalidated)) {
> > +		drm_dbg(&pxp->ctrl_gt->i915->drm, "PXP: creating arb_session after invalidation");
> >   		pxp_create_arb_session(pxp);
> > +	}
> >   
> >   	complete_all(&pxp->termination);
> >   }
> > @@ -157,6 +159,8 @@ static void pxp_session_work(struct work_struct *work)
> >   	if (!events)
> >   		return;
> >   
> > +	drm_dbg(&gt->i915->drm, "PXP: processing event-flags 0x%08x", events);
> > +
> >   	if (events & PXP_INVAL_REQUIRED)
> >   		intel_pxp_invalidate(pxp);
> >   
> > diff --git a/drivers/gpu/drm/i915/pxp/intel_pxp_types.h b/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
> > index 7e11fa8034b2..07864b584cf4 100644
> > --- a/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
> > +++ b/drivers/gpu/drm/i915/pxp/intel_pxp_types.h
> > @@ -124,6 +124,7 @@ struct intel_pxp {
> >   #define PXP_TERMINATION_REQUEST  BIT(0)
> >   #define PXP_TERMINATION_COMPLETE BIT(1)
> >   #define PXP_INVAL_REQUIRED       BIT(2)
> > +#define PXP_EVENT_TYPE_IRQ       BIT(3)
> >   };
> >   
> >   #endif /* __INTEL_PXP_TYPES_H__ */
> > 
> > base-commit: 5429d55de723544dfc0630cf39d96392052b27a1