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: Chris 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: Michał Winiarski <michal.winiarski@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1467616119-4093-6-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 80d162a..f0535df 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -351,9 +351,8 @@
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 @@
{
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 @@
~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 @@
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 @@
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 @@
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 @@
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);
}