Re: [PATCH] drm/i915: Disable idle messaging before ring disable

[Daniel Vetter <daniel@ffwll.ch>]

On Fri, May 22, 2015 at 08:18:46PM +0300, Mika Kuoppala wrote:
> According to bspec, with ring mode scheduling on gen >= 8,
> we need to disable ring idle message before writing zero to
> Ring Buffer Enable.
> 
> Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.h         |  2 ++
>  drivers/gpu/drm/i915/i915_reg.h         |  2 ++
>  drivers/gpu/drm/i915/intel_ringbuffer.c | 28 +++++++++++++++++++++++++++-
>  drivers/gpu/drm/i915/intel_uncore.c     | 12 ++++++++++++
>  4 files changed, 43 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 1038f5c..564c593 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2609,6 +2609,8 @@ void intel_uncore_forcewake_get__locked(struct drm_i915_private *dev_priv,
>  void intel_uncore_forcewake_put__locked(struct drm_i915_private *dev_priv,
>  					enum forcewake_domains domains);
>  void assert_forcewakes_inactive(struct drm_i915_private *dev_priv);
> +void assert_forcewakes_active(struct drm_i915_private *dev_priv);
> +
>  static inline bool intel_vgpu_active(struct drm_device *dev)
>  {
>  	return to_i915(dev)->vgpu.active;
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 6eeba63..9bead93 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -1643,6 +1643,8 @@ enum skl_disp_power_wells {
>  #define   GFX_PSMI_GRANULARITY		(1<<10)
>  #define   GFX_PPGTT_ENABLE		(1<<9)
>  
> +#define CSPWRFSM	0x022AC
> +
>  #define VLV_DISPLAY_BASE 0x180000
>  #define VLV_MIPI_BASE VLV_DISPLAY_BASE
>  
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index d934f85..c06dc76 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -531,6 +531,31 @@ static void intel_ring_setup_status_page(struct intel_engine_cs *ring)
>  	}
>  }
>  
> +static void disable_ring(struct intel_engine_cs *ring)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(ring->dev);
> +	const bool need_idle_disable = ring->id == RCS &&
> +		INTEL_INFO(ring->dev)->gen > 7;
> +
> +	assert_forcewakes_active(dev_priv);
> +
> +	if (need_idle_disable) {
> +		I915_WRITE(RING_PSMI_CTL(ring->mmio_base),
> +			   _MASKED_BIT_ENABLE(GEN6_PSMI_SLEEP_MSG_DISABLE));
> +
> +		if (wait_for((I915_READ(CSPWRFSM) & ((1 << 6) - 1)) == 0x30,
> +			     1000))
> +			DRM_ERROR("%s: disable idle msg timeout\n",
> +				  ring->name);
> +	}
> +
> +	I915_WRITE_CTL(ring, 0);
> +
> +	if (need_idle_disable)
> +		I915_WRITE(GEN6_RC_SLEEP_PSMI_CONTROL,
> +			   _MASKED_BIT_DISABLE(GEN6_PSMI_SLEEP_MSG_DISABLE));
> +}
> +
>  static bool stop_ring(struct intel_engine_cs *ring)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(ring->dev);
> @@ -548,7 +573,8 @@ static bool stop_ring(struct intel_engine_cs *ring)
>  		}
>  	}
>  
> -	I915_WRITE_CTL(ring, 0);
> +	disable_ring(ring);
> +
>  	I915_WRITE_HEAD(ring, 0);
>  	ring->write_tail(ring, 0);
>  
> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> index a6d8a3e..4e070e0 100644
> --- a/drivers/gpu/drm/i915/intel_uncore.c
> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> @@ -525,6 +525,18 @@ void assert_forcewakes_inactive(struct drm_i915_private *dev_priv)
>  		WARN_ON(domain->wake_count);
>  }
>  
> +void assert_forcewakes_active(struct drm_i915_private *dev_priv)

Just an side: kerneldoc for intel_uncore would be really nice ...
-Daniel

> +{
> +	struct intel_uncore_forcewake_domain *domain;
> +	enum forcewake_domain_id id;
> +
> +	if (!dev_priv->uncore.funcs.force_wake_get)
> +		return;
> +
> +	for_each_fw_domain(domain, dev_priv, id)
> +		WARN_ON(domain->wake_count == 0);
> +}
> +
>  /* We give fast paths for the really cool registers */
>  #define NEEDS_FORCE_WAKE(dev_priv, reg) \
>  	 ((reg) < 0x40000 && (reg) != FORCEWAKE)
> -- 
> 1.9.1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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