Re: [PATCH 16/19] drm/i915: sanity check power well sw state against hw state

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Feb 18, 2014 at 12:02:17AM +0200, Imre Deak wrote:
> Suggested by Daniel.
> 
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 33 ++++++++++++++++++++++++++++++---
>  1 file changed, 30 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index e81e7de..21ccf89 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -5338,6 +5338,24 @@ static void hsw_power_well_disable(struct drm_i915_private *dev_priv,
>  	hsw_enable_package_c8(dev_priv);
>  }
>  
> +static void check_power_well_state(struct drm_i915_private *dev_priv,
> +				   struct i915_power_well *power_well)
> +{
> +	bool enabled;
> +
> +	if (!power_well->ops->is_enabled)
> +		return;
> +
> +	enabled = power_well->ops->is_enabled(dev_priv, power_well);
> +
> +	if (enabled != (power_well->count > 0 || !i915.disable_power_well)) {

Doesn't i915.disable_power_well==true mean "leave power wells always
enabled"? So I think the '!' needs to be removed.

> +		DRM_ERROR("state mismatch for '%s' (hw state %d use-count %d disable_power_well %d\n",
> +			  power_well->name, enabled, power_well->count,
> +			  i915.disable_power_well);
> +		WARN_ON(1);
> +	}

For an error message + backtrace, you could just use WARN().

> +}
> +
>  void intel_display_power_get(struct drm_i915_private *dev_priv,
>  			     enum intel_display_power_domain domain)
>  {
> @@ -5349,9 +5367,14 @@ void intel_display_power_get(struct drm_i915_private *dev_priv,
>  
>  	mutex_lock(&power_domains->lock);
>  
> -	for_each_power_well(i, power_well, BIT(domain), power_domains)
> -		if (!power_well->count++ && power_well->ops->enable)
> +	for_each_power_well(i, power_well, BIT(domain), power_domains) {
> +		if (!power_well->count++ && power_well->ops->enable) {
> +			DRM_DEBUG_KMS("enabling %s\n", power_well->name);
>  			power_well->ops->enable(dev_priv, power_well);
> +		}
> +
> +		check_power_well_state(dev_priv, power_well);
> +	}
>  
>  	power_domains->domain_use_count[domain]++;
>  
> @@ -5376,8 +5399,12 @@ void intel_display_power_put(struct drm_i915_private *dev_priv,
>  		WARN_ON(!power_well->count);
>  
>  		if (!--power_well->count && power_well->ops->disable &&
> -		    i915.disable_power_well)
> +		    i915.disable_power_well) {
> +			DRM_DEBUG_KMS("disabling %s\n", power_well->name);
>  			power_well->ops->disable(dev_priv, power_well);
> +		}
> +
> +		check_power_well_state(dev_priv, power_well);
>  	}
>  
>  	mutex_unlock(&power_domains->lock);
> -- 
> 1.8.4
> 
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-- 
Ville Syrjälä
Intel OTC