Message-ID: <20210216180825.GA420119@ideak-desk.fi.intel.com>
Date:   Tue, 16 Feb 2021 20:08:25 +0200
From:   Imre Deak <imre.deak@...el.com>
To:     Lyude Paul <lyude@...hat.com>
Cc:     intel-gfx@...ts.freedesktop.org, David Airlie <airlied@...ux.ie>,
        open list <linux-kernel@...r.kernel.org>,
        "open list:DRM DRIVERS" <dri-devel@...ts.freedesktop.org>
Subject: Re: [Intel-gfx] [PATCH v2] drm/i915/gen9bc: Handle TGP PCH during
 suspend/resume

Hi,

thanks for respinning this patchset, some comments below.

On Fri, Feb 12, 2021 at 01:50:53PM -0500, Lyude Paul wrote:
> From: Tejas Upadhyay <tejaskumarx.surendrakumar.upadhyay@...el.com>
> 
> For Legacy S3 suspend/resume GEN9 BC needs to enable and
> setup TGP PCH.
> 
> v2:
> * Move Wa_14010685332 into it's own function - vsyrjala
> * Add TODO comment about figuring out if we can move this workaround - imre
> 
> Cc: Matt Roper <matthew.d.roper@...el.com>
> Signed-off-by: Tejas Upadhyay <tejaskumarx.surendrakumar.upadhyay@...el.com>
> Signed-off-by: Lyude Paul <lyude@...hat.com>
> ---
>  drivers/gpu/drm/i915/i915_irq.c | 53 ++++++++++++++++++++++-----------
>  1 file changed, 36 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 98145a7f28a4..7d912aa950ee 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -3040,6 +3040,19 @@ static void valleyview_irq_reset(struct drm_i915_private *dev_priv)
>  	spin_unlock_irq(&dev_priv->irq_lock);
>  }
>  
> +static void cnp_irq_post_reset(struct drm_i915_private *dev_priv)

Maybe a better name is cnp_display_clock_wa.

> +{
> +	struct intel_uncore *uncore = &dev_priv->uncore;
> +
> +	/*
> +	 * Wa_14010685332:cnp/cmp,tgp,adp

Bspec says this WA applies ICL onwards and it's not PCH specific, for
instance I haven't found the GEN9/CNP/CMP WA entries for it. Please also
add a 'clarify platforms where this applies' todo item.

> +	 * TODO: Figure out if this workaround can be applied in the s0ix suspend/resume handlers as
> +	 * on earlier platforms and whether the workaround is also needed for runtime suspend/resume
> +	 */
> +	intel_uncore_rmw(uncore, SOUTH_CHICKEN1, SBCLK_RUN_REFCLK_DIS, SBCLK_RUN_REFCLK_DIS);
> +	intel_uncore_rmw(uncore, SOUTH_CHICKEN1, SBCLK_RUN_REFCLK_DIS, 0);
> +}
> +
>  static void gen8_irq_reset(struct drm_i915_private *dev_priv)
>  {
>  	struct intel_uncore *uncore = &dev_priv->uncore;
> @@ -3061,8 +3074,14 @@ static void gen8_irq_reset(struct drm_i915_private *dev_priv)
>  	GEN3_IRQ_RESET(uncore, GEN8_DE_MISC_);
>  	GEN3_IRQ_RESET(uncore, GEN8_PCU_);
>  
> -	if (HAS_PCH_SPLIT(dev_priv))
> +	if (INTEL_PCH_TYPE(dev_priv) >= PCH_ICP)

It was mentioned already earlier, why is this check necessary and can't we
just call ibx_irq_reset() for all PCHs?

> +		GEN3_IRQ_RESET(uncore, SDE);
> +	else if (HAS_PCH_SPLIT(dev_priv))
>  		ibx_irq_reset(dev_priv);
> +
> +	if (INTEL_PCH_TYPE(dev_priv) == PCH_CNP ||
> +	    (INTEL_PCH_TYPE(dev_priv) >= PCH_TGP && INTEL_PCH_TYPE(dev_priv) < PCH_DG1))

The check could be also moved to the helper.

> +		cnp_irq_post_reset(dev_priv);
>  }
>  
>  static void gen11_display_irq_reset(struct drm_i915_private *dev_priv)
> @@ -3104,15 +3123,9 @@ static void gen11_display_irq_reset(struct drm_i915_private *dev_priv)
>  	if (INTEL_PCH_TYPE(dev_priv) >= PCH_ICP)
>  		GEN3_IRQ_RESET(uncore, SDE);
>  
> -	/* Wa_14010685332:cnp/cmp,tgp,adp */
>  	if (INTEL_PCH_TYPE(dev_priv) == PCH_CNP ||
> -	    (INTEL_PCH_TYPE(dev_priv) >= PCH_TGP &&
> -	     INTEL_PCH_TYPE(dev_priv) < PCH_DG1)) {
> -		intel_uncore_rmw(uncore, SOUTH_CHICKEN1,
> -				 SBCLK_RUN_REFCLK_DIS, SBCLK_RUN_REFCLK_DIS);
> -		intel_uncore_rmw(uncore, SOUTH_CHICKEN1,
> -				 SBCLK_RUN_REFCLK_DIS, 0);
> -	}
> +	    (INTEL_PCH_TYPE(dev_priv) >= PCH_TGP && INTEL_PCH_TYPE(dev_priv) < PCH_DG1))
> +		cnp_irq_post_reset(dev_priv);
>  }
>  
>  static void gen11_irq_reset(struct drm_i915_private *dev_priv)
> @@ -3474,6 +3487,9 @@ static void spt_hpd_irq_setup(struct drm_i915_private *dev_priv)
>  	ibx_display_interrupt_update(dev_priv, hotplug_irqs, enabled_irqs);
>  
>  	spt_hpd_detection_setup(dev_priv);
> +
> +	if (INTEL_PCH_TYPE(dev_priv) >= PCH_ICP)
> +		icp_hpd_irq_setup(dev_priv);

This doesn't look correct, icp_hpd_irq_setup() redoes the interrupt
setup done already earlier in this function and
spt_hpd_detection_setup() is probably also not correct on ICP+. Looks
like for ICP+ we need to call icp_hpd_irq_setup() instead of
spt_hpd_irq_setup(), but haven't checked in detail.

>  }
>  
>  static u32 ilk_hotplug_enables(struct drm_i915_private *i915,
> @@ -3764,9 +3780,19 @@ static void gen8_de_irq_postinstall(struct drm_i915_private *dev_priv)
>  	}
>  }
>  
> +static void icp_irq_postinstall(struct drm_i915_private *dev_priv)
> +{
> +	struct intel_uncore *uncore = &dev_priv->uncore;
> +	u32 mask = SDE_GMBUS_ICP;
> +
> +	GEN3_IRQ_INIT(uncore, SDE, ~mask, 0xffffffff);
> +}
> +
>  static void gen8_irq_postinstall(struct drm_i915_private *dev_priv)
>  {
> -	if (HAS_PCH_SPLIT(dev_priv))
> +	if (INTEL_PCH_TYPE(dev_priv) >= PCH_ICP)
> +		icp_irq_postinstall(dev_priv);
> +	else if (HAS_PCH_SPLIT(dev_priv))
>  		ibx_irq_postinstall(dev_priv);
>  
>  	gen8_gt_irq_postinstall(&dev_priv->gt);
> @@ -3775,13 +3801,6 @@ static void gen8_irq_postinstall(struct drm_i915_private *dev_priv)
>  	gen8_master_intr_enable(dev_priv->uncore.regs);
>  }
>  
> -static void icp_irq_postinstall(struct drm_i915_private *dev_priv)
> -{
> -	struct intel_uncore *uncore = &dev_priv->uncore;
> -	u32 mask = SDE_GMBUS_ICP;
> -
> -	GEN3_IRQ_INIT(uncore, SDE, ~mask, 0xffffffff);
> -}
>  
>  static void gen11_irq_postinstall(struct drm_i915_private *dev_priv)
>  {
> -- 
> 2.29.2
> 
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