[Intel-gfx] [PATCH] drm/i915: Squelch overzealous uncore reset WARN_ON

[Chris Wilson]

On Thu, Feb 05, 2015 at 05:45:42PM +0200, Mika Kuoppala wrote:
> We added this WARN_ON to guard against using uninitialized
> forcewake domains. But forgot blissfully that not all
> gens have forcewake domains in the first place.
> 
> v2: Move WARN_ON to fw_domains_init (Chris)
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88911
> Tested-by: Ding Heng <hengx.ding at intel.com> (v1)
> Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_uncore.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> index 76b60a3..e10bcfc 100644
> --- a/drivers/gpu/drm/i915/intel_uncore.c
> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> @@ -166,7 +166,8 @@ fw_domains_reset(struct drm_i915_private *dev_priv, enum forcewake_domains fw_do
>  	struct intel_uncore_forcewake_domain *d;
>  	enum forcewake_domain_id id;
>  
> -	WARN_ON(dev_priv->uncore.fw_domains == 0);
> +	if (dev_priv->uncore.fw_domains == 0)
> +		return;
>  
>  	for_each_fw_domain_mask(d, fw_domains, dev_priv, id)
>  		fw_domain_reset(d);
> @@ -997,6 +998,9 @@ static void intel_uncore_fw_domains_init(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  
> +	if (INTEL_INFO(dev_priv->dev)->gen <= 5)
> +		return;
> +
>  	if (IS_GEN9(dev)) {
>  		dev_priv->uncore.funcs.force_wake_get = fw_domains_get;
>  		dev_priv->uncore.funcs.force_wake_put = fw_domains_put;
> @@ -1069,6 +1073,8 @@ static void intel_uncore_fw_domains_init(struct drm_device *dev)
>  		fw_domain_init(dev_priv, FW_DOMAIN_ID_RENDER,
>  			       FORCEWAKE, FORCEWAKE_ACK);
>  	}
> +
Maybe: /* All future platforms are expected to require complex power gating */
> +	WARN_ON(dev_priv->uncore.fw_domains == 0);
>  }

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

-- 
Chris Wilson, Intel Open Source Technology Centre