-----Original Message----- From: Intel-gfx <[email protected]> On Behalf Of Nitin Gote Sent: Thursday, July 11, 2024 9:32 AM To: Wilson, Chris P <[email protected]>; [email protected]; [email protected] Cc: [email protected]; Shyti, Andi <[email protected]>; Das, Nirmoy <[email protected]>; [email protected]; Gote, Nitin R <[email protected]>; Chris Wilson <[email protected]>; [email protected] Subject: [PATCH v3] drm/i915/gt: Do not consider preemption during execlists_dequeue for gen8 > > We're seeing a GPU HANG issue on a CHV platform, which was caused by > bac24f59f454 ("drm/i915/execlists: Enable coarse preemption boundaries for > gen8"). > > Gen8 platform has only timeslice and doesn't support a preemption mechanism > as engines do not have a preemption timer and doesn't send an irq if the > preemption timeout expires.
That seems to mean the original can_preempt function was inaccurately built, so fixing it here makes the most sense to me, especially if it's causing problems. Reviewed-by: Jonathan Cavitt <[email protected]> -Jonathan Cavitt > So, add a fix to not consider preemption > during dequeuing for gen8 platforms. > > v2: Simplify can_preempt() function (Tvrtko Ursulin) > > v3: > - Inside need_preempt(), condition of can_preempt() is not required > as simplified can_preempt() is enough. (Chris Wilson) > > Fixes: bac24f59f454 ("drm/i915/execlists: Enable coarse preemption boundaries > for gen8") > Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/11396 > Suggested-by: Andi Shyti <[email protected]> > Signed-off-by: Nitin Gote <[email protected]> > Cc: Chris Wilson <[email protected]> > CC: <[email protected]> # v5.2+ > --- > drivers/gpu/drm/i915/gt/intel_execlists_submission.c | 6 +----- > 1 file changed, 1 insertion(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c > b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c > index 21829439e686..72090f52fb85 100644 > --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c > +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c > @@ -3315,11 +3315,7 @@ static void remove_from_engine(struct i915_request *rq) > > static bool can_preempt(struct intel_engine_cs *engine) > { > - if (GRAPHICS_VER(engine->i915) > 8) > - return true; > - > - /* GPGPU on bdw requires extra w/a; not implemented */ > - return engine->class != RENDER_CLASS; > + return GRAPHICS_VER(engine->i915) > 8; > } > > static void kick_execlists(const struct i915_request *rq, int prio) > -- > 2.25.1 > >
