Re: [PATCH 1/4] drm/i915/gen9+: Enable hotplug detection early

["Sharma, Shashank" <shashank.sharma@intel.com>]

Regards

Shashank


On 1/28/2017 1:24 PM, Imre Deak wrote:
> On Sat, Jan 28, 2017 at 10:24:19AM +0530, Sharma, Shashank wrote:
>> Regards
>>
>> Shashank
>>
>>
>> On 1/27/2017 3:09 PM, Imre Deak wrote:
>>> For LSPCON resume time initialization we need to sample the
>>> corresponding pin's HPD level, but this is only available when HPD
>>> detection is enabled. Currently we enable detection only when enabling
>>> HPD interrupts which is too late, so bring the enabling of detection
>>> earlier.
>>>
>>> This is needed by the next patch.
>>>
>>> Cc: Shashank Sharma <shashank.sharma@intel.com>
>>> Cc: Jani Nikula <jani.nikula@linux.intel.com>
>>> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
>>> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
>>> Cc: <stable@vger.kernel.org> # v4.9+
>>> Signed-off-by: Imre Deak <imre.deak@intel.com>
>>> ---
>>>   drivers/gpu/drm/i915/i915_irq.c | 71 +++++++++++++++++++++++++++++------------
>>>   1 file changed, 51 insertions(+), 20 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
>>> index 8440d8b..6daf522 100644
>>> --- a/drivers/gpu/drm/i915/i915_irq.c
>>> +++ b/drivers/gpu/drm/i915/i915_irq.c
>>> @@ -3142,24 +3142,33 @@ static void ibx_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>>   	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
>>>   }
>>> +static void spt_hpd_detection_setup(struct drm_i915_private *dev_priv)
>>> +{
>>> +	u32 hotplug;
>>> +
>>> +	/* Enable digital hotplug on the PCH */
>>> +	hotplug = I915_READ(PCH_PORT_HOTPLUG);
>>> +	hotplug |= PORTA_HOTPLUG_ENABLE |
>>> +		   PORTB_HOTPLUG_ENABLE |
>>> +		   PORTC_HOTPLUG_ENABLE |
>>> +		   PORTD_HOTPLUG_ENABLE;
>>> +	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
>>> +
>>> +	hotplug = I915_READ(PCH_PORT_HOTPLUG2);
>>> +	hotplug |= PORTE_HOTPLUG_ENABLE;
>>> +	I915_WRITE(PCH_PORT_HOTPLUG2, hotplug);
>>> +}
>>> +
>>>   static void spt_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>>   {
>>> -	u32 hotplug_irqs, hotplug, enabled_irqs;
>>> +	u32 hotplug_irqs, enabled_irqs;
>>>   	hotplug_irqs = SDE_HOTPLUG_MASK_SPT;
>>>   	enabled_irqs = intel_hpd_enabled_irqs(dev_priv, hpd_spt);
>>>   	ibx_display_interrupt_update(dev_priv, hotplug_irqs, enabled_irqs);
>>> -	/* Enable digital hotplug on the PCH */
>>> -	hotplug = I915_READ(PCH_PORT_HOTPLUG);
>>> -	hotplug |= PORTD_HOTPLUG_ENABLE | PORTC_HOTPLUG_ENABLE |
>>> -		PORTB_HOTPLUG_ENABLE | PORTA_HOTPLUG_ENABLE;
>>> -	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
>>> -
>>> -	hotplug = I915_READ(PCH_PORT_HOTPLUG2);
>>> -	hotplug |= PORTE_HOTPLUG_ENABLE;
>>> -	I915_WRITE(PCH_PORT_HOTPLUG2, hotplug);
>>> +	spt_hpd_detection_setup(dev_priv);
>>>   }
>>>   static void ilk_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>> @@ -3196,18 +3205,15 @@ static void ilk_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>>   	ibx_hpd_irq_setup(dev_priv);
>>>   }
>>> -static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>> +static void __bxt_hpd_detection_setup(struct drm_i915_private *dev_priv,
>>> +					     u32 enabled_irqs)
>>>   {
>>> -	u32 hotplug_irqs, hotplug, enabled_irqs;
>>> -
>>> -	enabled_irqs = intel_hpd_enabled_irqs(dev_priv, hpd_bxt);
>>> -	hotplug_irqs = BXT_DE_PORT_HOTPLUG_MASK;
>>> -
>>> -	bdw_update_port_irq(dev_priv, hotplug_irqs, enabled_irqs);
>>> +	u32 hotplug;
>>>   	hotplug = I915_READ(PCH_PORT_HOTPLUG);
>>> -	hotplug |= PORTC_HOTPLUG_ENABLE | PORTB_HOTPLUG_ENABLE |
>>> -		PORTA_HOTPLUG_ENABLE;
>>> +	hotplug |= PORTA_HOTPLUG_ENABLE |
>>> +		   PORTB_HOTPLUG_ENABLE |
>>> +		   PORTC_HOTPLUG_ENABLE;
>>>   	DRM_DEBUG_KMS("Invert bit setting: hp_ctl:%x hp_port:%x\n",
>>>   		      hotplug, enabled_irqs);
>>> @@ -3217,7 +3223,6 @@ static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>>   	 * For BXT invert bit has to be set based on AOB design
>>>   	 * for HPD detection logic, update it based on VBT fields.
>>>   	 */
>>> -
>>>   	if ((enabled_irqs & BXT_DE_PORT_HP_DDIA) &&
>>>   	    intel_bios_is_port_hpd_inverted(dev_priv, PORT_A))
>>>   		hotplug |= BXT_DDIA_HPD_INVERT;
>>> @@ -3231,6 +3236,23 @@ static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>>   	I915_WRITE(PCH_PORT_HOTPLUG, hotplug);
>>>   }
>>> +static void bxt_hpd_detection_setup(struct drm_i915_private *dev_priv)
>>> +{
>>> +	__bxt_hpd_detection_setup(dev_priv, BXT_DE_PORT_HOTPLUG_MASK);
>> Do we need another layer of internal function ? Why cant the content of
>> __bxt_hpd_detection_setup be here, just
>> like spd_hpd_detection_setup, as they both are static to the file ?
> The port configuration is platform specific and so I wanted to keep it
> close to where the rest of HPD setup is done. The caller of
> bxt_hpd_detection_setup() only cares about enabling detection on _all_
> ports as the other *_hpd_detection_setup() helpers.
I am not very convinced, but seems no harm too :)
>>> +}
>>> +
>>> +static void bxt_hpd_irq_setup(struct drm_i915_private *dev_priv)
>>> +{
>>> +	u32 hotplug_irqs, enabled_irqs;
>>> +
>>> +	enabled_irqs = intel_hpd_enabled_irqs(dev_priv, hpd_bxt);
>>> +	hotplug_irqs = BXT_DE_PORT_HOTPLUG_MASK;
>>> +
>>> +	bdw_update_port_irq(dev_priv, hotplug_irqs, enabled_irqs);
>>> +
>>> +	__bxt_hpd_detection_setup(dev_priv, enabled_irqs);
>>> +}
>>> +
>>>   static void ibx_irq_postinstall(struct drm_device *dev)
>>>   {
>>>   	struct drm_i915_private *dev_priv = to_i915(dev);
>>> @@ -3246,6 +3268,12 @@ static void ibx_irq_postinstall(struct drm_device *dev)
>>>   	gen5_assert_iir_is_zero(dev_priv, SDEIIR);
>>>   	I915_WRITE(SDEIMR, ~mask);
>>> +
>>> +	if (HAS_PCH_IBX(dev_priv) || HAS_PCH_CPT(dev_priv) ||
>>> +	    HAS_PCH_LPT(dev_priv))
>>> +		; /* TODO: Enable HPD detection on older PCH platforms too */
>>> +	else
>>> +		spt_hpd_detection_setup(dev_priv);
>>>   }
>>>   static void gen5_gt_irq_postinstall(struct drm_device *dev)
>>> @@ -3457,6 +3485,9 @@ static void gen8_de_irq_postinstall(struct drm_i915_private *dev_priv)
>>>   	GEN5_IRQ_INIT(GEN8_DE_PORT_, ~de_port_masked, de_port_enables);
>>>   	GEN5_IRQ_INIT(GEN8_DE_MISC_, ~de_misc_masked, de_misc_masked);
>>> +
>>> +	if (IS_GEN9_LP(dev_priv))
>> I have not done the delta analysis between hotplug interrupts, but this will
>> be true for GLK too.
>> Should we bother ?
> The GLK HPD detection setup and interrupt setup and handling is the same as
> on BXT. See bxt_hpd_irq_setup() and bxt_hpd_irq_handler() that are
> called on GLK as well.
Yep, I was wandering about SCDC kind of interrupts, which are new in 
GLK, but probably I should
take care of it, while writing the code for that.

Reviewed-by: Shashank Sharma <shashank.sharma@intel.com>
>> - Shashank
>>> +		bxt_hpd_detection_setup(dev_priv);
>>>   }
>>>   static int gen8_irq_postinstall(struct drm_device *dev)

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