[Intel-gfx] [RFC PATCH 53/97] drm/i915/guc: Disable semaphores when using GuC scheduling

[Matthew Brost]

On Tue, May 25, 2021 at 10:52:01AM +0100, Tvrtko Ursulin wrote:
> 
> On 06/05/2021 20:14, Matthew Brost wrote:
> > Disable semaphores when using GuC scheduling as semaphores are broken in
> > the current GuC firmware.
> 
> What is "current"? Given that the patch itself is like year and a half old.
> 

Stale comment. Semaphore work with the firmware we just haven't enabled
them in the i915 with GuC submission as this an optimization and not
required for functionality.

Matt

> Regards,
> 
> Tvrtko
> 
> > Cc: John Harrison <john.c.harrison at intel.com>
> > Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> > ---
> >   drivers/gpu/drm/i915/gem/i915_gem_context.c | 6 ++++--
> >   1 file changed, 4 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> > index 993faa213b41..d30260ffe2a7 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
> > @@ -230,7 +230,8 @@ static void intel_context_set_gem(struct intel_context *ce,
> >   		ce->timeline = intel_timeline_get(ctx->timeline);
> >   	if (ctx->sched.priority >= I915_PRIORITY_NORMAL &&
> > -	    intel_engine_has_timeslices(ce->engine))
> > +	    intel_engine_has_timeslices(ce->engine) &&
> > +	    intel_engine_has_semaphores(ce->engine))
> >   		__set_bit(CONTEXT_USE_SEMAPHORES, &ce->flags);
> >   	intel_context_set_watchdog_us(ce, ctx->watchdog.timeout_us);
> > @@ -1939,7 +1940,8 @@ static int __apply_priority(struct intel_context *ce, void *arg)
> >   	if (!intel_engine_has_timeslices(ce->engine))
> >   		return 0;
> > -	if (ctx->sched.priority >= I915_PRIORITY_NORMAL)
> > +	if (ctx->sched.priority >= I915_PRIORITY_NORMAL &&
> > +	    intel_engine_has_semaphores(ce->engine))
> >   		intel_context_set_use_semaphores(ce);
> >   	else
> >   		intel_context_clear_use_semaphores(ce);
> >