[Intel-gfx] [PATCH 1/5] drm/i915/execlists: Set priority hint prior to submission

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> Since we now run process_csb() outside of the engine->active.lock, we
> can process a CS-event immediately upon our ELSP write. As we currently
> inspect the pending queue *after* the ELSP write, there is an
> opportunity for a CS-event to update the pending queue before we can
> read it, making ourselves chases an invalid pointer.
>
> Fixes: df403069029d ("drm/i915/execlists: Lift process_csb() out of the irq-off spinlock")
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>

Reviewed-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>

> ---
>  drivers/gpu/drm/i915/gt/intel_lrc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
> index 44780e7fafec..d42584439f51 100644
> --- a/drivers/gpu/drm/i915/gt/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
> @@ -1335,9 +1335,9 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
>  	if (submit) {
>  		*port = execlists_schedule_in(last, port - execlists->pending);
>  		memset(port + 1, 0, (last_port - port) * sizeof(*port));
> -		execlists_submit_ports(engine);
>  		execlists->switch_priority_hint =
>  			switch_prio(engine, *execlists->pending);
> +		execlists_submit_ports(engine);
>  	} else {
>  		ring_set_paused(engine, 0);
>  	}
> -- 
> 2.23.0.rc1