Re: [PATCH 26/49] drm/i915/bxt: Add BXT support in gen8_irq functions

[Jani Nikula <jani.nikula@linux.intel.com>]

On Tue, 17 Mar 2015, Imre Deak <imre.deak@intel.com> wrote:
> From: Shashank Sharma <shashank.sharma@intel.com>
>
> This patch adds conditional checks in gen8_irq functions
> to support BXT. Most of the checks just look for PCH split
> availability, and block the call to PCH interrupt functions if
> not available.
>
> Reviewed-by: Satheeshakrishna M <satheeshakrishna.m@intel.com>
> Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
> Signed-off-by: Shashank Sharma <ppashank.sharma@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_irq.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 4a2f85b..3b82eb2 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -2372,7 +2372,13 @@ static irqreturn_t gen8_irq_handler(int irq, void *arg)
>  			DRM_ERROR("The master control interrupt lied (DE PIPE)!\n");
>  	}
>  
> -	if (!HAS_PCH_NOP(dev) && master_ctl & GEN8_DE_PCH_IRQ) {
> +	/*
> +	 * Todo: BXT doesnt have a PCH, so GEN8_DE_PCH_IRQ shouldn't
> +	 * be set. But until this part is confirmed, going paranoid, and adding
> +	 * a IS_BROXTON check here.
> +	 */
> +	if (!IS_BROXTON(dev) && !HAS_PCH_NOP(dev) &&
> +			master_ctl & GEN8_DE_PCH_IRQ) {

Drop the todo comment, and add HAS_PCH_SPLIT() instead of !IS_BROXTON()
here, and it's fine. We never want to call pch functions on non-pch
platforms, so this is IMO the obvious thing to do.

>  		/*
>  		 * FIXME(BDW): Assume for now that the new interrupt handling
>  		 * scheme also closed the SDE interrupt handling race we've seen
> @@ -3096,7 +3102,7 @@ static void ibx_irq_reset(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  
> -	if (HAS_PCH_NOP(dev))
> +	if (HAS_PCH_NOP(dev) || !HAS_PCH_SPLIT(dev))
>  		return;

No, I think it's much better to simply not call pch functions on non-pch
platforms. Instead, please add

	if (HAS_PCH_SPLIT(dev))
        	ibx_irq_reset(dev);

in gen8_irq_reset().

>  
>  	GEN5_IRQ_RESET(SDE);
> @@ -3117,7 +3123,7 @@ static void ibx_irq_pre_postinstall(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  
> -	if (HAS_PCH_NOP(dev))
> +	if (HAS_PCH_NOP(dev) || !HAS_PCH_SPLIT(dev))
>  		return;

Same here, but for gen8_irq_postinstall().

>  
>  	WARN_ON(I915_READ(SDEIER) != 0);
> @@ -3325,7 +3331,7 @@ static void ibx_irq_postinstall(struct drm_device *dev)
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	u32 mask;
>  
> -	if (HAS_PCH_NOP(dev))
> +	if (HAS_PCH_NOP(dev) || !HAS_PCH_SPLIT(dev))
>  		return;

Ditto.

>  
>  	if (HAS_PCH_IBX(dev))
> -- 
> 2.1.0
>
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-- 
Jani Nikula, Intel Open Source Technology Center
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