Re: [PATCH] drm/i915: get a PC8 reference when enabling the power well

[Daniel Vetter <daniel@ffwll.ch>]

On Fri, Dec 13, 2013 at 05:46:38PM -0200, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni@intel.com>
> 
> In the current code, at haswell_modeset_global_resources, first we
> decide if we want to enable/disable the power well, then we decide if
> we want to enable/disable PC8. On the case where we're enabling PC8
> this works fine, but on the case where we disable PC8 due to a non-eDP
> monitor being enabled, we first enable the power well and then disable
> PC8. Although wrong, this doesn't seem to be causing any problems now,
> and we don't even see anything in dmesg. But the patches for runtime
> D3 turn this problem into a real bug, so we need to fix it.
> 
> This fixes the "modeset-non-lpsp" subtest from the "pm_pc8" test from
> intel-gpu-tools.
> 
> v2: - Rebase (i915_disable_power_well).
> v3: - More reabase.
> v4: - Rebase on top of -fixes instead of -nightly.
> 
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>

Applied to -fixes, thanks.
-Daniel
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 3657ab4..26c29c1 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -5688,6 +5688,8 @@ static void __intel_set_power_well(struct drm_device *dev, bool enable)
>  	unsigned long irqflags;
>  	uint32_t tmp;
>  
> +	WARN_ON(dev_priv->pc8.enabled);
> +
>  	tmp = I915_READ(HSW_PWR_WELL_DRIVER);
>  	is_enabled = tmp & HSW_PWR_WELL_STATE_ENABLED;
>  	enable_requested = tmp & HSW_PWR_WELL_ENABLE_REQUEST;
> @@ -5747,16 +5749,24 @@ static void __intel_set_power_well(struct drm_device *dev, bool enable)
>  static void __intel_power_well_get(struct drm_device *dev,
>  				   struct i915_power_well *power_well)
>  {
> -	if (!power_well->count++)
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +
> +	if (!power_well->count++) {
> +		hsw_disable_package_c8(dev_priv);
>  		__intel_set_power_well(dev, true);
> +	}
>  }
>  
>  static void __intel_power_well_put(struct drm_device *dev,
>  				   struct i915_power_well *power_well)
>  {
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +
>  	WARN_ON(!power_well->count);
> -	if (!--power_well->count && i915_disable_power_well)
> +	if (!--power_well->count && i915_disable_power_well) {
>  		__intel_set_power_well(dev, false);
> +		hsw_enable_package_c8(dev_priv);
> +	}
>  }
>  
>  void intel_display_power_get(struct drm_device *dev,
> -- 
> 1.8.3.1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch