Re: [PATCH 2/2] drm/i915: Simplify the IVB interrupt handler

Daniel Vetter
2012-05-06T15:36:43Z

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 <chris@chris-wilson.co.uk>

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
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

--
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48