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Commit c33d247d authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Flush the RPS bottom-half when the GPU idles 



Make sure that the RPS bottom-half is flushed before we set the idle
frequency when we decide the GPU is idle. This should prevent any races
with the bottom-half and setting the idle frequency, and ensures that
the bottom-half is bounded by the GPU's rpm reference taken for when it
is active (i.e. between gen6_rps_busy() and gen6_rps_idle()).

v2: Avoid recursively using the i915->wq - RPS does not touch the
struct_mutex so has no place being on the ordered i915->wq.
v3: Enable/disable interrupts for RPS busy/idle in order to prevent
further HW access from RPS outside of the wakeref.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
References: https://bugs.freedesktop.org/show_bug.cgi?id=89728


Reviewed-by: default avatarMichał Winiarski <michal.winiarski@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1467616119-4093-6-git-send-email-chris@chris-wilson.co.uk
parent df4ba509

drivers/gpu/drm/i915/i915_drv.c

+0 −3
Original line number Diff line number Diff line
@@ -2737,7 +2737,6 @@ static int intel_runtime_suspend(struct device *device) 


	intel_guc_suspend(dev);



	intel_suspend_gt_powersave(dev_priv);

	intel_runtime_pm_disable_interrupts(dev_priv);



	ret = 0;
@@ -2852,8 +2851,6 @@ static int intel_runtime_resume(struct device *device) 
	if (!IS_VALLEYVIEW(dev_priv) && !IS_CHERRYVIEW(dev_priv))

		intel_hpd_init(dev_priv);



	intel_enable_gt_powersave(dev_priv);



	enable_rpm_wakeref_asserts(dev_priv);



	if (ret)

drivers/gpu/drm/i915/i915_irq.c

+12 −20
Original line number Diff line number Diff line
@@ -351,9 +351,8 @@ void gen6_reset_rps_interrupts(struct drm_i915_private *dev_priv) 
void gen6_enable_rps_interrupts(struct drm_i915_private *dev_priv)

{

	spin_lock_irq(&dev_priv->irq_lock);



	WARN_ON(dev_priv->rps.pm_iir);

	WARN_ON(I915_READ(gen6_pm_iir(dev_priv)) & dev_priv->pm_rps_events);

	WARN_ON_ONCE(dev_priv->rps.pm_iir);

	WARN_ON_ONCE(I915_READ(gen6_pm_iir(dev_priv)) & dev_priv->pm_rps_events);

	dev_priv->rps.interrupts_enabled = true;

	I915_WRITE(gen6_pm_ier(dev_priv), I915_READ(gen6_pm_ier(dev_priv)) |

				dev_priv->pm_rps_events);
@@ -371,11 +370,6 @@ void gen6_disable_rps_interrupts(struct drm_i915_private *dev_priv) 
{

	spin_lock_irq(&dev_priv->irq_lock);

	dev_priv->rps.interrupts_enabled = false;

	spin_unlock_irq(&dev_priv->irq_lock);



	cancel_work_sync(&dev_priv->rps.work);



	spin_lock_irq(&dev_priv->irq_lock);



	I915_WRITE(GEN6_PMINTRMSK, gen6_sanitize_rps_pm_mask(dev_priv, ~0));
@@ -384,8 +378,15 @@ void gen6_disable_rps_interrupts(struct drm_i915_private *dev_priv) 
				~dev_priv->pm_rps_events);



	spin_unlock_irq(&dev_priv->irq_lock);



	synchronize_irq(dev_priv->dev->irq);



	/* Now that we will not be generating any more work, flush any

	 * outsanding tasks. As we are called on the RPS idle path,

	 * we will reset the GPU to minimum frequencies, so the current

	 * state of the worker can be discarded.

	 */

	cancel_work_sync(&dev_priv->rps.work);

	gen6_reset_rps_interrupts(dev_priv);

}



/**
@@ -1082,13 +1083,6 @@ static void gen6_pm_rps_work(struct work_struct *work) 
		return;

	}



	/*

	 * The RPS work is synced during runtime suspend, we don't require a

	 * wakeref. TODO: instead of disabling the asserts make sure that we

	 * always hold an RPM reference while the work is running.

	 */

	DISABLE_RPM_WAKEREF_ASSERTS(dev_priv);



	pm_iir = dev_priv->rps.pm_iir;

	dev_priv->rps.pm_iir = 0;

	/* Make sure not to corrupt PMIMR state used by ringbuffer on GEN6 */
@@ -1101,7 +1095,7 @@ static void gen6_pm_rps_work(struct work_struct *work) 
	WARN_ON(pm_iir & ~dev_priv->pm_rps_events);



	if ((pm_iir & dev_priv->pm_rps_events) == 0 && !client_boost)

		goto out;

		return;



	mutex_lock(&dev_priv->rps.hw_lock);
@@ -1156,8 +1150,6 @@ static void gen6_pm_rps_work(struct work_struct *work) 
	intel_set_rps(dev_priv, new_delay);



	mutex_unlock(&dev_priv->rps.hw_lock);

out:

	ENABLE_RPM_WAKEREF_ASSERTS(dev_priv);

}
@@ -1597,7 +1589,7 @@ static void gen6_rps_irq_handler(struct drm_i915_private *dev_priv, u32 pm_iir) 
		gen6_disable_pm_irq(dev_priv, pm_iir & dev_priv->pm_rps_events);

		if (dev_priv->rps.interrupts_enabled) {

			dev_priv->rps.pm_iir |= pm_iir & dev_priv->pm_rps_events;

			queue_work(dev_priv->wq, &dev_priv->rps.work);

			schedule_work(&dev_priv->rps.work);

		}

		spin_unlock(&dev_priv->irq_lock);

	}

drivers/gpu/drm/i915/intel_pm.c

+10 −1
Original line number Diff line number Diff line
@@ -4864,6 +4864,8 @@ void gen6_rps_busy(struct drm_i915_private *dev_priv) 
		I915_WRITE(GEN6_PMINTRMSK,

			   gen6_rps_pm_mask(dev_priv, dev_priv->rps.cur_freq));



		gen6_enable_rps_interrupts(dev_priv);



		/* Ensure we start at the user's desired frequency */

		intel_set_rps(dev_priv,

			      clamp(dev_priv->rps.cur_freq,
@@ -4875,6 +4877,13 @@ void gen6_rps_busy(struct drm_i915_private *dev_priv) 


void gen6_rps_idle(struct drm_i915_private *dev_priv)

{

	/* Flush our bottom-half so that it does not race with us

	 * setting the idle frequency and so that it is bounded by

	 * our rpm wakeref. And then disable the interrupts to stop any

	 * futher RPS reclocking whilst we are asleep.

	 */

	gen6_disable_rps_interrupts(dev_priv);



	mutex_lock(&dev_priv->rps.hw_lock);

	if (dev_priv->rps.enabled) {

		if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
@@ -4915,7 +4924,7 @@ void gen6_rps_boost(struct drm_i915_private *dev_priv, 
		spin_lock_irq(&dev_priv->irq_lock);

		if (dev_priv->rps.interrupts_enabled) {

			dev_priv->rps.client_boost = true;

			queue_work(dev_priv->wq, &dev_priv->rps.work);

			schedule_work(&dev_priv->rps.work);

		}

		spin_unlock_irq(&dev_priv->irq_lock);