[Intel-xe] [Intel-gfx] [PATCH v2 19/27] drm/i915/xe2lpd: Add support for HPD

[Matt Roper]

On Thu, Sep 07, 2023 at 08:37:49AM -0700, Lucas De Marchi wrote:
> From: Gustavo Sousa <gustavo.sousa at intel.com>
> 
> Hotplug setup for Xe2_LPD differs from Xe_LPD+ by the fact that the
> extra programming for hotplug inversion and DDI HPD filter duration is
> not necessary anymore. As mtp_hpd_irq_setup() is reasonably small,
> prefer to fork it into a new function for Xe2_LPD instead of adding a
> platform check.
> 
> v2: Add extra bspec reference and fix missing else (Matt Roper)
> 
> BSpec: 68970, 69940
> Signed-off-by: Gustavo Sousa <gustavo.sousa at intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>

This matches the spec, so

Reviewed-by: Matt Roper <matthew.d.roper at intel.com>

However the programming of SHPD_FILTER_CNT on Meteor Lake was never
something that was documented in the bspec; it looks like it was added
in 4948738e296c ("drm/i915/hotplug: Reduce SHPD_FILTER to 250us") and
tracing back the discussion there is looks like we decided we didn't
like the steps that were actually suggested for Wa_14013120569 and just
decided to do our own thing rather than working with the hardware team
to clarify/update/fix the officially documented workaround.  Even
ignoring the fact that that wasn't an appropriate process for handling
workarounds, Wa_14013120569 (which was the true impetus here) isn't
listed as applying to MTL either, so we probably shouldn't really be
programming SHPD_FILTER_CNT in mtp_hpd_irq_setup either.


Matt

> ---
>  .../gpu/drm/i915/display/intel_hotplug_irq.c  | 21 +++++++++++++++++--
>  1 file changed, 19 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_hotplug_irq.c b/drivers/gpu/drm/i915/display/intel_hotplug_irq.c
> index 3398cc21bd26..f07047e9cb30 100644
> --- a/drivers/gpu/drm/i915/display/intel_hotplug_irq.c
> +++ b/drivers/gpu/drm/i915/display/intel_hotplug_irq.c
> @@ -163,7 +163,9 @@ static void intel_hpd_init_pins(struct drm_i915_private *dev_priv)
>  	    (!HAS_PCH_SPLIT(dev_priv) || HAS_PCH_NOP(dev_priv)))
>  		return;
>  
> -	if (INTEL_PCH_TYPE(dev_priv) >= PCH_DG1)
> +	if (INTEL_PCH_TYPE(dev_priv) >= PCH_LNL)
> +		hpd->pch_hpd = hpd_mtp;
> +	else if (INTEL_PCH_TYPE(dev_priv) >= PCH_DG1)
>  		hpd->pch_hpd = hpd_sde_dg1;
>  	else if (INTEL_PCH_TYPE(dev_priv) >= PCH_MTP)
>  		hpd->pch_hpd = hpd_mtp;
> @@ -1063,6 +1065,19 @@ static void mtp_hpd_irq_setup(struct drm_i915_private *i915)
>  	mtp_tc_hpd_detection_setup(i915);
>  }
>  
> +static void xe2lpd_sde_hpd_irq_setup(struct drm_i915_private *i915)
> +{
> +	u32 hotplug_irqs, enabled_irqs;
> +
> +	enabled_irqs = intel_hpd_enabled_irqs(i915, i915->display.hotplug.pch_hpd);
> +	hotplug_irqs = intel_hpd_hotplug_irqs(i915, i915->display.hotplug.pch_hpd);
> +
> +	ibx_display_interrupt_update(i915, hotplug_irqs, enabled_irqs);
> +
> +	mtp_ddi_hpd_detection_setup(i915);
> +	mtp_tc_hpd_detection_setup(i915);
> +}
> +
>  static bool is_xelpdp_pica_hpd_pin(enum hpd_pin hpd_pin)
>  {
>  	return hpd_pin >= HPD_PORT_TC1 && hpd_pin <= HPD_PORT_TC4;
> @@ -1122,7 +1137,9 @@ static void xelpdp_hpd_irq_setup(struct drm_i915_private *i915)
>  
>  	xelpdp_pica_hpd_detection_setup(i915);
>  
> -	if (INTEL_PCH_TYPE(i915) >= PCH_MTP)
> +	if (INTEL_PCH_TYPE(i915) >= PCH_LNL)
> +		xe2lpd_sde_hpd_irq_setup(i915);
> +	else if (INTEL_PCH_TYPE(i915) >= PCH_MTP)
>  		mtp_hpd_irq_setup(i915);
>  }
>  
> -- 
> 2.40.1
> 

-- 
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation