Re: [PATCH 7/8] drm/i915/skl: Assert the requirements to enter or exit DC6.

[Imre Deak <imre.deak@intel.com>]

On Wed, 2015-04-01 at 16:22 +0530, Animesh Manna wrote:
> From: Suketu Shah <suketu.j.shah@intel.com>
> 
> Warn if the conditions to enter or exit DC6 are not satisfied such
> as support for runtime PM, state of power well, CSR loading etc.
> 
> v2: Removed camelcase in functions and variables.
> 
> v3: Do some minimal check to assert if CSR program is not loaded.
> 
> v4:
> 1] Correct the check for backlight-disabling in assert_can_enable_dc6().
> 2] Check csr.loaded = false before disabling DC6 and simplify other checks.
> 
> v5:
> 1] Remove checks for DC5 state from assert_can_enable_dc6 function as DC5 is no
>    longer enabled before enabling DC6.
> 2] Correct the check for CSR-loading in assert_can_disable_dc6 function as CSR must
>    be loaded for context restore to happen on DC6 disabling.
> 
> v6:
> 1] It's okay to explicitly disable DC6 during driver-load/resume even though it might
>    already be disabled and so don't warn about it.
> 
> v7: Rebase to latest.
> 
> v8: Sqashed the patch from Imre -
> [PATCH] drm/i915/skl: avoid false CSR fw not loaded WARN during driver load/resume
> 
> v9: After adding dmc ver 1.0 support rebased on top of nightly. (Animesh)
> 
> Issue: VIZ-2819
> Signed-off-by: A.Sunil Kamath <sunil.kamath@intel.com>
> Signed-off-by: Suketu Shah <suketu.j.shah@intel.com>
> Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
> Signed-off-by: Animesh Manna <animesh.manna@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_runtime_pm.c | 38 +++++++++++++++++++++++++++------
>  1 file changed, 32 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index cc94503..9196de3 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -1,5 +1,5 @@
> -/*
> - * Copyright © 2012-2014 Intel Corporation
> +		/*
> + * Cipyright © 2012-2014 Intel Corporation

Unintentional change.

>   *
>   * Permission is hereby granted, free of charge, to any person obtaining a
>   * copy of this software and associated documentation files (the "Software"),
> @@ -408,12 +408,39 @@ static void gen9_disable_dc5(struct drm_i915_private *dev_priv)
>  	POSTING_READ(DC_STATE_EN);
>  }
>  
> -static void skl_enable_dc6(struct drm_i915_private *dev_priv)
> +static void assert_can_enable_dc6(struct drm_i915_private *dev_priv)
>  {
>  	struct drm_device *dev = dev_priv->dev;
> +
> +	WARN(!IS_SKYLAKE(dev), "Platform doesn't support DC6.\n");
> +	WARN(!HAS_RUNTIME_PM(dev), "Runtime PM not enabled.\n");
> +	WARN(I915_READ(UTIL_PIN_CTL) & UTIL_PIN_ENABLE,
> +		"Backlight is not disabled.\n");
> +	WARN((I915_READ(DC_STATE_EN) & DC_STATE_EN_UPTO_DC6),
> +		"DC6 already programmed to be enabled.\n");
> +
> +	assert_csr_loaded(dev_priv);
> +}
> +
> +static void assert_can_disable_dc6(struct drm_i915_private *dev_priv)
> +{
> +	/*
> +	 * During initialization, the firmware may not be loaded yet.
> +	 * We still want to make sure that the DC enabling flag is cleared.
> +	 */
> +	if (dev_priv->power_domains.initializing)
> +		return;

I missed this earlier, but this early return should also be added to
assert_can_disable_dc5().

With the above fixed:
Reviewed-by: Imre Deak <imre.deak@intel.com>

> +
> +	assert_csr_loaded(dev_priv);
> +	WARN(!(I915_READ(DC_STATE_EN) & DC_STATE_EN_UPTO_DC6),
> +		"DC6 already programmed to be disabled.\n");
> +}
> +
> +static void skl_enable_dc6(struct drm_i915_private *dev_priv)
> +{
>  	uint32_t val;
>  
> -	WARN_ON(!IS_SKYLAKE(dev));
> +	assert_can_enable_dc6(dev_priv);
>  
>  	DRM_DEBUG_KMS("Enabling DC6\n");
>  
> @@ -428,10 +455,9 @@ static void skl_enable_dc6(struct drm_i915_private *dev_priv)
>  
>  static void skl_disable_dc6(struct drm_i915_private *dev_priv)
>  {
> -	struct drm_device *dev = dev_priv->dev;
>  	uint32_t val;
>  
> -	WARN_ON(!IS_SKYLAKE(dev));
> +	assert_can_disable_dc6(dev_priv);
>  
>  	DRM_DEBUG_KMS("Disabling DC6\n");
>  


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