Re: [PATCH 11/19] drm/i915: disable interrupts when enabling PC8

[Daniel Vetter <daniel@ffwll.ch>]

On Thu, Nov 21, 2013 at 01:47:25PM -0200, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni@intel.com>
> 
> The plan is to merge PC8 and D3 into a single feature, and when we're
> in D3 we won't get any hotplug interrupt anyway, so leaving them
> enable doesn't make sense, and it also brings us a problem. The
> problem is that we get a hotplug interrupt right when we we wake up
> from D3, when we're still waking up everything. If we fully disable
> interrupts we won't get this hotplug interrupt, so we won't have
> problems.
> 
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>

Now that we forgo the partial interrupt enabling of pc8 there's imo no
need any more for the pc8 interrup reg save/restore dance. Instead it'd be
much better to just disable the interrup by disabling the interrupt
handler and then when reenabling things to use our core interrupt enabling
functions.

This way the runtime d3 path uses the same code as resume and driver load.
Furthermore the D3 code will be a bit more generic, which helps with
enabling platforms. But this can (should) be done in a follow-up.
-Daniel
> ---
>  drivers/gpu/drm/i915/i915_irq.c | 26 +++++++++-----------------
>  1 file changed, 9 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 70c4cef..d0f4e61 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -3902,8 +3902,8 @@ void hsw_pc8_disable_interrupts(struct drm_device *dev)
>  	dev_priv->pc8.regsave.gtier = I915_READ(GTIER);
>  	dev_priv->pc8.regsave.gen6_pmimr = I915_READ(GEN6_PMIMR);
>  
> -	ironlake_disable_display_irq(dev_priv, ~DE_PCH_EVENT_IVB);
> -	ibx_disable_display_interrupt(dev_priv, ~SDE_HOTPLUG_MASK_CPT);
> +	ironlake_disable_display_irq(dev_priv, 0xffffffff);
> +	ibx_disable_display_interrupt(dev_priv, 0xffffffff);
>  	ilk_disable_gt_irq(dev_priv, 0xffffffff);
>  	snb_disable_pm_irq(dev_priv, 0xffffffff);
>  
> @@ -3917,34 +3917,26 @@ void hsw_pc8_restore_interrupts(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	unsigned long irqflags;
> -	uint32_t val, expected;
> +	uint32_t val;
>  
>  	spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
>  
>  	val = I915_READ(DEIMR);
> -	expected = ~DE_PCH_EVENT_IVB;
> -	WARN(val != expected, "DEIMR is 0x%08x, not 0x%08x\n", val, expected);
> +	WARN(val != 0xffffffff, "DEIMR is 0x%08x\n", val);
>  
> -	val = I915_READ(SDEIMR) & ~SDE_HOTPLUG_MASK_CPT;
> -	expected = ~SDE_HOTPLUG_MASK_CPT;
> -	WARN(val != expected, "SDEIMR non-HPD bits are 0x%08x, not 0x%08x\n",
> -	     val, expected);
> +	val = I915_READ(SDEIMR);
> +	WARN(val != 0xffffffff, "SDEIMR is 0x%08x\n", val);
>  
>  	val = I915_READ(GTIMR);
> -	expected = 0xffffffff;
> -	WARN(val != expected, "GTIMR is 0x%08x, not 0x%08x\n", val, expected);
> +	WARN(val != 0xffffffff, "GTIMR is 0x%08x\n", val);
>  
>  	val = I915_READ(GEN6_PMIMR);
> -	expected = 0xffffffff;
> -	WARN(val != expected, "GEN6_PMIMR is 0x%08x, not 0x%08x\n", val,
> -	     expected);
> +	WARN(val != 0xffffffff, "GEN6_PMIMR is 0x%08x\n", val);
>  
>  	dev_priv->pc8.irqs_disabled = false;
>  
>  	ironlake_enable_display_irq(dev_priv, ~dev_priv->pc8.regsave.deimr);
> -	ibx_enable_display_interrupt(dev_priv,
> -				     ~dev_priv->pc8.regsave.sdeimr &
> -				     ~SDE_HOTPLUG_MASK_CPT);
> +	ibx_enable_display_interrupt(dev_priv, ~dev_priv->pc8.regsave.sdeimr);
>  	ilk_enable_gt_irq(dev_priv, ~dev_priv->pc8.regsave.gtimr);
>  	snb_enable_pm_irq(dev_priv, ~dev_priv->pc8.regsave.gen6_pmimr);
>  	I915_WRITE(GTIER, dev_priv->pc8.regsave.gtier);
> -- 
> 1.8.3.1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch