Re: [Intel-gfx] [PATCH] Revert "drm/i915: re-order if/else ladder for hpd_irq_setup"

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: intel-gfx@lists.freedesktop.org, Chris Wilson <chris@chris-wilson.co.uk>
Subject: Re: [Intel-gfx] [PATCH] Revert "drm/i915: re-order if/else ladder for hpd_irq_setup"
Date: Mon, 30 Nov 2020 16:19:54 +0200	[thread overview]
Message-ID: <20201130141954.GS6112@intel.com> (raw)
In-Reply-To: <20201128045229.kvxiqjin7k67zkod@ldmartin-desk1>

On Fri, Nov 27, 2020 at 08:52:29PM -0800, Lucas De Marchi wrote:
> On Fri, Nov 27, 2020 at 02:57:48PM +0000, Chris Wilson wrote:
> >We now use ilk_hpd_irq_setup for all GMCH platforms that do not have
> >hotplug. These are early gen3 and gen2 devices that now explode on boot
> >as they try to access non-existent registers.
> 
> humn... true, my bad. But I don't think a revert is the right fix. It
> would be much better if we would not be setting up the hpd setup
> function at all for platforms that do not have hotplug. I think a
> separate early check for I915_HAS_HOTPLUG() would be deserved.

I think it generally leads to much less convoluted logic when we keep
gmch vs. rest separate. So I'm confused as to what we're even trying
to achieve here?

> 
> Lucas De Marchi
> 
> >
> >Fixes: 794d61a19090 ("drm/i915: re-order if/else ladder for hpd_irq_setup")
> >Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> >Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> >Cc: José Roberto de Souza <jose.souza@intel.com>
> >Cc: Jani Nikula <jani.nikula@linux.intel.com>
> 
> 
> >---
> > drivers/gpu/drm/i915/i915_irq.c | 27 +++++++++++++++------------
> > 1 file changed, 15 insertions(+), 12 deletions(-)
> >
> >diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> >index dc6febc63f1c..c80eeac53952 100644
> >--- a/drivers/gpu/drm/i915/i915_irq.c
> >+++ b/drivers/gpu/drm/i915/i915_irq.c
> >@@ -4242,18 +4242,21 @@ void intel_irq_init(struct drm_i915_private *dev_priv)
> > 	 */
> > 	dev_priv->hotplug.hpd_short_storm_enabled = !HAS_DP_MST(dev_priv);
> >
> >-	if (HAS_PCH_DG1(dev_priv))
> >-		dev_priv->display.hpd_irq_setup = dg1_hpd_irq_setup;
> >-	else if (INTEL_GEN(dev_priv) >= 11)
> >-		dev_priv->display.hpd_irq_setup = gen11_hpd_irq_setup;
> >-	else if (IS_GEN9_LP(dev_priv))
> >-		dev_priv->display.hpd_irq_setup = bxt_hpd_irq_setup;
> >-	else if (INTEL_PCH_TYPE(dev_priv) >= PCH_SPT)
> >-		dev_priv->display.hpd_irq_setup = spt_hpd_irq_setup;
> >-	else if (HAS_GMCH(dev_priv) && I915_HAS_HOTPLUG(dev_priv))
> >-		dev_priv->display.hpd_irq_setup = i915_hpd_irq_setup;
> >-	else
> >-		dev_priv->display.hpd_irq_setup = ilk_hpd_irq_setup;
> >+	if (HAS_GMCH(dev_priv)) {
> >+		if (I915_HAS_HOTPLUG(dev_priv))
> >+			dev_priv->display.hpd_irq_setup = i915_hpd_irq_setup;
> >+	} else {
> >+		if (HAS_PCH_DG1(dev_priv))
> >+			dev_priv->display.hpd_irq_setup = dg1_hpd_irq_setup;
> >+		else if (INTEL_GEN(dev_priv) >= 11)
> >+			dev_priv->display.hpd_irq_setup = gen11_hpd_irq_setup;
> >+		else if (IS_GEN9_LP(dev_priv))
> >+			dev_priv->display.hpd_irq_setup = bxt_hpd_irq_setup;
> >+		else if (INTEL_PCH_TYPE(dev_priv) >= PCH_SPT)
> >+			dev_priv->display.hpd_irq_setup = spt_hpd_irq_setup;
> >+		else
> >+			dev_priv->display.hpd_irq_setup = ilk_hpd_irq_setup;
> >+	}
> > }
> >
> > /**
> >-- 
> >2.20.1
> >
> _______________________________________________
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> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel
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