On Wed, May 02, 2012 at 09:52:13AM +0100, Chris Wilson wrote:
> Reduce the number of reads and writes required for handling a single
> interrupt.
> 
> Signed-off-by: Chris Wilson <[email protected]>

Ok, I've looked at this again and imo it does too much. On a quick look we
have adding the pch_iir argument to pch_irq_handler and restructuring the
register read/write sequence in the actual handler. The latter seems to
require that we unconditionally return IRQ_HANDLED. And the diff looks a
bit horrible ...
-Daniel

> ---
>  drivers/gpu/drm/i915/i915_irq.c |   94 
> ++++++++++++++++-----------------------
>  1 file changed, 38 insertions(+), 56 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 7d1fc62..72c85f0 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -533,14 +533,11 @@ out:
>       return ret;
>  }
>  
> -static void pch_irq_handler(struct drm_device *dev)
> +static void pch_irq_handler(struct drm_device *dev, u32 pch_iir)
>  {
>       drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
> -     u32 pch_iir;
>       int pipe;
>  
> -     pch_iir = I915_READ(SDEIIR);
> -
>       if (pch_iir & SDE_AUDIO_POWER_MASK)
>               DRM_DEBUG_DRIVER("PCH audio power change on port %d\n",
>                                (pch_iir & SDE_AUDIO_POWER_MASK) >>
> @@ -580,26 +577,15 @@ static irqreturn_t ivybridge_irq_handler(DRM_IRQ_ARGS)
>  {
>       struct drm_device *dev = (struct drm_device *) arg;
>       drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
> -     int ret = IRQ_NONE;
> -     u32 de_iir, gt_iir, de_ier, pch_iir, pm_iir;
> +     u32 de_iir, gt_iir, de_ier, pm_iir;
>       struct drm_i915_master_private *master_priv;
> +     int i;
>  
>       atomic_inc(&dev_priv->irq_received);
>  
>       /* disable master interrupt before clearing iir  */
>       de_ier = I915_READ(DEIER);
>       I915_WRITE(DEIER, de_ier & ~DE_MASTER_IRQ_CONTROL);
> -     POSTING_READ(DEIER);
> -
> -     de_iir = I915_READ(DEIIR);
> -     gt_iir = I915_READ(GTIIR);
> -     pch_iir = I915_READ(SDEIIR);
> -     pm_iir = I915_READ(GEN6_PMIIR);
> -
> -     if (de_iir == 0 && gt_iir == 0 && pch_iir == 0 && pm_iir == 0)
> -             goto done;
> -
> -     ret = IRQ_HANDLED;
>  
>       if (dev->primary->master) {
>               master_priv = dev->primary->master->driver_priv;
> @@ -608,56 +594,52 @@ static irqreturn_t ivybridge_irq_handler(DRM_IRQ_ARGS)
>                               READ_BREADCRUMB(dev_priv);
>       }
>  
> -     snb_gt_irq_handler(dev, dev_priv, gt_iir);
> -
> -     if (de_iir & DE_GSE_IVB)
> -             intel_opregion_gse_intr(dev);
> -
> -     if (de_iir & DE_PLANEA_FLIP_DONE_IVB) {
> -             intel_prepare_page_flip(dev, 0);
> -             intel_finish_page_flip_plane(dev, 0);
> -     }
> -
> -     if (de_iir & DE_PLANEB_FLIP_DONE_IVB) {
> -             intel_prepare_page_flip(dev, 1);
> -             intel_finish_page_flip_plane(dev, 1);
> +     gt_iir = I915_READ(GTIIR);
> +     if (gt_iir) {
> +             snb_gt_irq_handler(dev, dev_priv, gt_iir);
> +             I915_WRITE(GTIIR, gt_iir);
>       }
>  
> -     if (de_iir & DE_PLANEC_FLIP_DONE_IVB) {
> -             intel_prepare_page_flip(dev, 2);
> -             intel_finish_page_flip_plane(dev, 2);
> -     }
> +     de_iir = I915_READ(DEIIR);
> +     if (de_iir) {
> +             if (de_iir & DE_GSE_IVB)
> +                     intel_opregion_gse_intr(dev);
> +
> +             for (i = 0; i < 3; i++) {
> +                     if (de_iir & (DE_PLANEA_FLIP_DONE_IVB << (5 * i))) {
> +                             intel_prepare_page_flip(dev, i);
> +                             intel_finish_page_flip_plane(dev, i);
> +                     }
> +                     if (de_iir & (DE_PIPEA_VBLANK_IVB << (5 * i)))
> +                             drm_handle_vblank(dev, i);
> +             }
>  
> -     if (de_iir & DE_PIPEA_VBLANK_IVB)
> -             drm_handle_vblank(dev, 0);
> +             /* check event from PCH */
> +             if (de_iir & DE_PCH_EVENT_IVB) {
> +                     u32 pch_iir = I915_READ(SDEIIR);
>  
> -     if (de_iir & DE_PIPEB_VBLANK_IVB)
> -             drm_handle_vblank(dev, 1);
> +                     if (pch_iir & SDE_HOTPLUG_MASK_CPT)
> +                             queue_work(dev_priv->wq, 
> &dev_priv->hotplug_work);
> +                     pch_irq_handler(dev, pch_iir);
>  
> -     if (de_iir & DE_PIPEC_VBLANK_IVB)
> -             drm_handle_vblank(dev, 2);
> +                     /* clear PCH hotplug event before clear CPU irq */
> +                     I915_WRITE(SDEIIR, pch_iir);
> +             }
>  
> -     /* check event from PCH */
> -     if (de_iir & DE_PCH_EVENT_IVB) {
> -             if (pch_iir & SDE_HOTPLUG_MASK_CPT)
> -                     queue_work(dev_priv->wq, &dev_priv->hotplug_work);
> -             pch_irq_handler(dev);
> +             I915_WRITE(DEIIR, de_iir);
>       }
>  
> -     if (pm_iir & GEN6_PM_DEFERRED_EVENTS)
> -             gen6_queue_rps_work(dev_priv, pm_iir);
> -
> -     /* should clear PCH hotplug event before clear CPU irq */
> -     I915_WRITE(SDEIIR, pch_iir);
> -     I915_WRITE(GTIIR, gt_iir);
> -     I915_WRITE(DEIIR, de_iir);
> -     I915_WRITE(GEN6_PMIIR, pm_iir);
> +     pm_iir = I915_READ(GEN6_PMIIR);
> +     if (pm_iir) {
> +             if (pm_iir & GEN6_PM_DEFERRED_EVENTS)
> +                     gen6_queue_rps_work(dev_priv, pm_iir);
> +             I915_WRITE(GEN6_PMIIR, pm_iir);
> +     }
>  
> -done:
>       I915_WRITE(DEIER, de_ier);
>       POSTING_READ(DEIER);
>  
> -     return ret;
> +     return IRQ_HANDLED;
>  }
>  
>  static void ilk_gt_irq_handler(struct drm_device *dev,
> @@ -737,7 +719,7 @@ static irqreturn_t ironlake_irq_handler(DRM_IRQ_ARGS)
>       if (de_iir & DE_PCH_EVENT) {
>               if (pch_iir & hotplug_mask)
>                       queue_work(dev_priv->wq, &dev_priv->hotplug_work);
> -             pch_irq_handler(dev);
> +             pch_irq_handler(dev, pch_iir);
>       }
>  
>       if (de_iir & DE_PCU_EVENT) {
> -- 
> 1.7.10
> 
> _______________________________________________
> Intel-gfx mailing list
> [email protected]
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Mail: [email protected]
Mobile: +41 (0)79 365 57 48
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