Re: [PATCH v2 17/21] drm/i915: sanity check power well sw state against hw state

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Tue,  4 Mar 2014 19:23:06 +0200
Imre Deak <imre.deak@intel.com> wrote:

> Suggested by Daniel.
> 
> v2:
> - sanitize the state checking condition, the original was rather
>   confusing (partly due to the unfortunate naming of
>   i915.disable_power_well) (Ville)
> - simpler message+backtrace generation by using WARN instead of WARN_ON
>   (Ville)
> - check if always-on power wells are truly on all the time
> 
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 38 +++++++++++++++++++++++++++++++++++---
>  1 file changed, 35 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 28fae53..c034842 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -5350,6 +5350,29 @@ static bool i9xx_always_on_power_well_enabled(struct drm_i915_private *dev_priv,
>  	return true;
>  }
>  
> +static void check_power_well_state(struct drm_i915_private *dev_priv,
> +				   struct i915_power_well *power_well)
> +{
> +	bool enabled = power_well->ops->is_enabled(dev_priv, power_well);
> +
> +	if (power_well->always_on || !i915.disable_power_well) {
> +		if (!enabled)
> +			goto mismatch;
> +
> +		return;
> +	}
> +
> +	if (enabled != (power_well->count > 0))
> +		goto mismatch;
> +
> +	return;
> +
> +mismatch:
> +	WARN(1, "state mismatch for '%s' (always_on %d hw state %d use-count %d disable_power_well %d\n",
> +		  power_well->name, power_well->always_on, enabled,
> +		  power_well->count, i915.disable_power_well);
> +}
> +
>  void intel_display_power_get(struct drm_i915_private *dev_priv,
>  			     enum intel_display_power_domain domain)
>  {
> @@ -5361,9 +5384,14 @@ 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++)
> +	for_each_power_well(i, power_well, BIT(domain), power_domains) {
> +		if (!power_well->count++) {
> +			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]++;
>  
> @@ -5387,8 +5415,12 @@ void intel_display_power_put(struct drm_i915_private *dev_priv,
>  	for_each_power_well_rev(i, power_well, BIT(domain), power_domains) {
>  		WARN_ON(!power_well->count);
>  
> -		if (!--power_well->count && i915.disable_power_well)
> +		if (!--power_well->count && 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);

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>

-- 
Jesse Barnes, Intel Open Source Technology Center