[Intel-gfx] [PATCH v2 06/18] drm/i915: Check for duplicated power well IDs

[Ville Syrjälä]

On Fri, Jul 07, 2017 at 05:39:07PM +0300, Imre Deak wrote:
> Check that all the power well IDs are unique on the given platform.
> 
> v2:
> - Fix using BIT_ULL() instead of BIT() for 64 bit mask.
> 
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_runtime_pm.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index 27c69f9..bc17d2f 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -2563,6 +2563,8 @@ static uint32_t get_allowed_dc_mask(const struct drm_i915_private *dev_priv,
>  int intel_power_domains_init(struct drm_i915_private *dev_priv)
>  {
>  	struct i915_power_domains *power_domains = &dev_priv->power_domains;
> +	u64 power_well_ids;
> +	int i;
>  
>  	i915.disable_power_well = sanitize_disable_power_well_option(dev_priv,
>  						     i915.disable_power_well);
> @@ -2599,6 +2601,15 @@ int intel_power_domains_init(struct drm_i915_private *dev_priv)
>  		set_power_wells(power_domains, i9xx_always_on_power_well);
>  	}
>  
> +	power_well_ids = 0;
> +	for (i = 0; i < power_domains->power_well_count; i++) {
> +		enum i915_power_well_id id = power_domains->power_wells[i].id;
> +
> +		WARN_ON(id >= sizeof(power_well_ids) * 8);
> +		WARN_ON(power_well_ids & BIT_ULL(id));
> +		power_well_ids |= BIT_ULL(id);
> +	}

Like Rodrigo, I was also worried about conflicting power well IDs, but
this should at least give us a runtime warning. Compile time error
would be nicer, but I guess there's no good way to do that.

Maybe pull this code into a separate functions called
assert_power_well_ids_unique() or something like that? That way you
wouldn't have to actually read the code to figure out what it's doing.

> +
>  	return 0;
>  }
>  
> -- 
> 2.7.4
> 
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-- 
Ville Syrjälä
Intel OTC