Re: [PATCH 5/5] drm/i915: Enable HPD interrupts with master ctl interrupt

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Nov 23, 2016 at 09:48:27PM +0530, Animesh Manna wrote:
> While suspending the device hpd related interrupts are enabled
> to get the interrupt when device is in suspend state.
> 
> Though display is in DC9 but system can be in S0 or S0i3 state.
> Hot plug during S0 state will generate de_port_interrupt but if
> system is in S0i3 state then display driver will get hotplug
> interrupt as pcu_hpd_interrupt which will come via pmc. So
> added the interrupt handling for pcu hpd interrupt.
> 
> Signed-off-by: Animesh Manna <animesh.manna@intel.com>
> Signed-off-by: A.Sunil Kamath <sunil.kamath@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_irq.c | 56 ++++++++++++++++++++++++++++++++++++++---
>  drivers/gpu/drm/i915/i915_reg.h | 12 +++++++++
>  2 files changed, 65 insertions(+), 3 deletions(-)
>  mode change 100644 => 100755 drivers/gpu/drm/i915/i915_irq.c
> 
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> old mode 100644
> new mode 100755
> index cb8a75f..2f9b604
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -110,9 +110,9 @@
>  
>  /* BXT hpd list */
>  static const u32 hpd_bxt[HPD_NUM_PINS] = {
> -	[HPD_PORT_A] = BXT_DE_PORT_HP_DDIA,
> -	[HPD_PORT_B] = BXT_DE_PORT_HP_DDIB,
> -	[HPD_PORT_C] = BXT_DE_PORT_HP_DDIC
> +	[HPD_PORT_A] = (BXT_DE_PORT_HP_DDIA | BXT_PCU_DC9_HP_DDIA),
> +	[HPD_PORT_B] = (BXT_DE_PORT_HP_DDIB | BXT_PCU_DC9_HP_DDIB),
> +	[HPD_PORT_C] = (BXT_DE_PORT_HP_DDIC | BXT_PCU_DC9_HP_DDIC)

hpd_bxt_pcu[]

>  };
>  
>  /* IIR can theoretically queue up two events. Be paranoid. */
> @@ -2463,6 +2463,24 @@ static void bxt_hpd_irq_handler(struct drm_i915_private *dev_priv,
>  			DRM_ERROR("The master control interrupt lied (DE PORT)!\n");
>  	}
>  
> +	if (master_ctl & GEN8_PCU_IRQ) {
> +		iir = I915_READ(GEN8_PCU_IIR);
> +		if (iir) {
> +			u32 tmp_mask;
> +

Please add a proper pcu irq ack/handler pair. I actually have such a
thing sitting on a branch:

git://github.com/vsyrjala/linux.git pcode_irq

> +			I915_WRITE(GEN8_PCU_IIR, iir);
> +			ret = IRQ_HANDLED;
> +			if (IS_BROXTON(dev_priv)) {
> +				tmp_mask = iir & BXT_PCU_DC9_HOTPLUG_MASK;
> +				if (tmp_mask)
> +					bxt_hpd_irq_handler(dev_priv, tmp_mask,
> +							hpd_bxt);

Umm. Does the PCH_HOTPLUG reg actually work in this "hpd redirected to
pcu" state? As in are we going to detect long vs. short pulses correctly
if you just use bxt_hpd_irq_handler()?

> +			} else
> +				DRM_ERROR("Unexpected PCU interrupt\n");
> +		} else
> +			DRM_ERROR("The master control interrupt lied (PCU)!\n");
> +	}
> +
>  	for_each_pipe(dev_priv, pipe) {
>  		u32 flip_done, fault_errors;
>  
> @@ -4294,6 +4312,19 @@ void intel_irq_uninstall(struct drm_i915_private *dev_priv)
>  	dev_priv->pm.irqs_enabled = false;
>  }
>  
> +static void bxt_enable_pcu_interrupt(struct drm_i915_private *dev_priv)
> +{
> +	u32 de_pcu_hpd_enable_mask, de_pcu_imr, de_pcu_ier;
> +
> +	de_pcu_hpd_enable_mask = GEN9_DE_PCU_PORTA_HOTPLUG |
> +				GEN9_DE_PCU_PORTB_HOTPLUG |
> +				GEN9_DE_PCU_PORTC_HOTPLUG;
> +
> +	de_pcu_imr = (I915_READ(GEN8_PCU_IMR) & 0x0);
> +	de_pcu_ier = (I915_READ(GEN8_PCU_IER) | de_pcu_hpd_enable_mask);

You'll want a bdw_update_pcu_irq() or some such thing.

> +	GEN5_IRQ_INIT(GEN8_PCU_, de_pcu_imr, de_pcu_ier);
> +}
> +
>  /**
>   * intel_runtime_pm_disable_interrupts - runtime interrupt disabling
>   * @dev_priv: i915 device instance
> @@ -4303,8 +4334,27 @@ void intel_irq_uninstall(struct drm_i915_private *dev_priv)
>   */
>  void intel_runtime_pm_disable_interrupts(struct drm_i915_private *dev_priv)
>  {
> +	unsigned long flags = 0;
> +
>  	dev_priv->drm.driver->irq_uninstall(&dev_priv->drm);
>  	dev_priv->pm.irqs_enabled = false;
> +
> +	if (IS_BROXTON(dev_priv) && dev_priv->vbt.hpd_wakeup_enabled) {
> +
> +		/* Enable HPD related interrupts during DC9 for HPD wakeup */
> +
> +		I915_WRITE(GEN8_MASTER_IRQ, GEN8_MASTER_IRQ_CONTROL);
> +		POSTING_READ(GEN8_MASTER_IRQ);
> +
> +		spin_lock_irqsave(&dev_priv->irq_lock, flags);
> +		if (dev_priv->display.hpd_irq_setup)
> +			dev_priv->display.hpd_irq_setup(dev_priv);
> +		spin_unlock_irqrestore(&dev_priv->irq_lock, flags);
> +
> +		bxt_enable_pcu_interrupt(dev_priv);
> +
> +		dev_priv->pm.irqs_enabled = true;
> +	}
>  	synchronize_irq(dev_priv->drm.irq);
>  }
>  
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 3361d7f..df89025 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6030,6 +6030,18 @@ enum {
>  #define GEN8_PCU_IIR _MMIO(0x444e8)
>  #define GEN8_PCU_IER _MMIO(0x444ec)
>  
> +/* BXT PCU DC9 hotplug control */
> +#define BXT_PCU_DC9_HP_DDIA		(1<<31)
> +#define BXT_PCU_DC9_HP_DDIB		(1<<30)
> +#define BXT_PCU_DC9_HP_DDIC		(1<<29)
> +#define BXT_PCU_DC9_HOTPLUG_MASK	(BXT_PCU_DC9_HP_DDIA | \
> +					 BXT_PCU_DC9_HP_DDIB | \
> +					 BXT_PCU_DC9_HP_DDIC)
> +
> +#define GEN9_DE_PCU_PORTA_HOTPLUG      (1 << 31)
> +#define GEN9_DE_PCU_PORTB_HOTPLUG      (1 << 30)
> +#define GEN9_DE_PCU_PORTC_HOTPLUG      (1 << 29)

Two names for the same bits?

> +
>  #define ILK_DISPLAY_CHICKEN2	_MMIO(0x42004)
>  /* Required on all Ironlake and Sandybridge according to the B-Spec. */
>  #define  ILK_ELPIN_409_SELECT	(1 << 25)
> -- 
> 1.9.1
> 
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-- 
Ville Syrjälä
Intel OTC
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