Re: [PATCH 4/6] drm/i915/opregion: abstract ASLE presence check

[Jani Nikula <jani.nikula@intel.com>]

On Thu, 11 Jan 2024, Radhakrishna Sripada <radhakrishna.sripada@intel.com> wrote:
> On Thu, Jan 11, 2024 at 07:21:17PM +0200, Jani Nikula wrote:
>> Add a function to check the opregion ASLE presence instead of accessing
>> the opregion structures directly.
>> 
>> Reorder the checks in i915_has_asle() to avoid the function call if
>> possible.
>> 
>> Cc: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>> ---
>>  drivers/gpu/drm/i915/display/intel_display_irq.c | 6 +++---
>>  drivers/gpu/drm/i915/display/intel_opregion.c    | 5 +++++
>>  drivers/gpu/drm/i915/display/intel_opregion.h    | 6 ++++++
>>  3 files changed, 14 insertions(+), 3 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/display/intel_display_irq.c b/drivers/gpu/drm/i915/display/intel_display_irq.c
>> index 99843883cef7..f846c5b108b5 100644
>> --- a/drivers/gpu/drm/i915/display/intel_display_irq.c
>> +++ b/drivers/gpu/drm/i915/display/intel_display_irq.c
>> @@ -266,12 +266,12 @@ void i915_disable_pipestat(struct drm_i915_private *dev_priv,
>>  	intel_uncore_posting_read(&dev_priv->uncore, reg);
>>  }
>>  
>> -static bool i915_has_asle(struct drm_i915_private *dev_priv)
>> +static bool i915_has_asle(struct drm_i915_private *i915)
> Why not move this to intel_opregion.c and export it instead of
> intel_opregion_asle_present ?

I'm trying to be conscious of the possible performance impact of making
calls from the irq code just to find there's nothing to do.

>>  {
>> -	if (!dev_priv->display.opregion.asle)
>> +	if (!IS_PINEVIEW(i915) && !IS_MOBILE(i915))
> Can we extend this check to dgfx as well?

Extend how? This will return early for everything after IVB.

BR,
Jani.

>
> -Radhakrishna(RK) Sripada
>
>>  		return false;
>>  
>> -	return IS_PINEVIEW(dev_priv) || IS_MOBILE(dev_priv);
>> +	return intel_opregion_asle_present(i915);
>>  }
>>  
>>  /**
>> diff --git a/drivers/gpu/drm/i915/display/intel_opregion.c b/drivers/gpu/drm/i915/display/intel_opregion.c
>> index 8b9e820971cb..26aacb01f9ec 100644
>> --- a/drivers/gpu/drm/i915/display/intel_opregion.c
>> +++ b/drivers/gpu/drm/i915/display/intel_opregion.c
>> @@ -632,6 +632,11 @@ static void asle_work(struct work_struct *work)
>>  	asle->aslc = aslc_stat;
>>  }
>>  
>> +bool intel_opregion_asle_present(struct drm_i915_private *i915)
>> +{
>> +	return i915->display.opregion.asle;
>> +}
>> +
>>  void intel_opregion_asle_intr(struct drm_i915_private *dev_priv)
>>  {
>>  	if (dev_priv->display.opregion.asle)
>> diff --git a/drivers/gpu/drm/i915/display/intel_opregion.h b/drivers/gpu/drm/i915/display/intel_opregion.h
>> index 9efadfb72584..d084b30e8703 100644
>> --- a/drivers/gpu/drm/i915/display/intel_opregion.h
>> +++ b/drivers/gpu/drm/i915/display/intel_opregion.h
>> @@ -69,6 +69,7 @@ void intel_opregion_resume(struct drm_i915_private *dev_priv);
>>  void intel_opregion_suspend(struct drm_i915_private *dev_priv,
>>  			    pci_power_t state);
>>  
>> +bool intel_opregion_asle_present(struct drm_i915_private *i915);
>>  void intel_opregion_asle_intr(struct drm_i915_private *dev_priv);
>>  int intel_opregion_notify_encoder(struct intel_encoder *intel_encoder,
>>  				  bool enable);
>> @@ -111,6 +112,11 @@ static inline void intel_opregion_suspend(struct drm_i915_private *dev_priv,
>>  {
>>  }
>>  
>> +static inline bool intel_opregion_asle_present(struct drm_i915_private *i915)
>> +{
>> +	return false;
>> +}
>> +
>>  static inline void intel_opregion_asle_intr(struct drm_i915_private *dev_priv)
>>  {
>>  }
>> -- 
>> 2.39.2
>> 

-- 
Jani Nikula, Intel