[Intel-gfx] [PATCH 1/3] drm/i915: Use intel_engine_stop_cs when stopping ringbuffer

[Chris Wilson]

Quoting Mika Kuoppala (2019-02-27 16:58:48)
> We have an exported function for stopping the engine before
> disabling a ringbuffer. Take it into use.
> 
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_engine_cs.c  |  3 +++
>  drivers/gpu/drm/i915/intel_ringbuffer.c | 31 +++++++++++--------------
>  2 files changed, 16 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
> index 4f244019560d..3feb0f74c239 100644
> --- a/drivers/gpu/drm/i915/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/intel_engine_cs.c
> @@ -817,6 +817,9 @@ void intel_engine_cancel_stop_cs(struct intel_engine_cs *engine)
>  {
>         struct drm_i915_private *dev_priv = engine->i915;
>  
> +       if (INTEL_GEN(dev_priv) < 3)
> +               return;
> +
>         GEM_TRACE("%s\n", engine->name);
>  
>         I915_WRITE_FW(RING_MI_MODE(engine->mmio_base),
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index 1b96b0960adc..5363dad1208d 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -607,23 +607,19 @@ static void ring_setup_status_page(struct intel_engine_cs *engine)
>  static bool stop_ring(struct intel_engine_cs *engine)
>  {
>         struct drm_i915_private *dev_priv = engine->i915;
> +       int ret;
>  
> -       if (INTEL_GEN(dev_priv) > 2) {
> -               I915_WRITE_MODE(engine, _MASKED_BIT_ENABLE(STOP_RING));
> -               if (intel_wait_for_register(dev_priv,
> -                                           RING_MI_MODE(engine->mmio_base),
> -                                           MODE_IDLE,
> -                                           MODE_IDLE,
> -                                           1000)) {
> -                       DRM_ERROR("%s : timed out trying to stop ring\n",
> -                                 engine->name);
> -                       /* Sometimes we observe that the idle flag is not
> -                        * set even though the ring is empty. So double
> -                        * check before giving up.
> -                        */
> -                       if (I915_READ_HEAD(engine) != I915_READ_TAIL(engine))
> -                               return false;
> -               }
> +       ret = intel_engine_stop_cs(engine);
> +       if (ret == -ENODEV)
> +               ret = 0;
> +
> +       if (ret) {
> +               /* Sometimes we observe that the idle flag is not

As you go past, gradually switch over to
/*
 * Sometimes...
style. The joys of a slow transition to uniformity and switching styles
half way through.

> +                * set even though the ring is empty. So double
> +                * check before giving up.
> +                */
> +               if (I915_READ_HEAD(engine) != I915_READ_TAIL(engine))
> +                       return false;
>         }
>  
>         I915_WRITE_HEAD(engine, I915_READ_TAIL(engine));
> @@ -718,8 +714,7 @@ static int init_ring_common(struct intel_engine_cs *engine)
>                 goto out;
>         }
>  
> -       if (INTEL_GEN(dev_priv) > 2)
> -               I915_WRITE_MODE(engine, _MASKED_BIT_DISABLE(STOP_RING));
> +       intel_engine_cancel_stop_cs(engine);
>  
>         /* Now awake, let it get started */
>         if (ring->tail != ring->head) {

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