drm/i915: Restore current RPS state after reset

Following commit 821ed7df6e2a ("drm/i915: Update reset path to fix
incomplete requests") we no longer mark the context as lost on reset as
we keep the requests (and contexts) alive. However, RPS remains reset
and we need to restore the current state to match the in-flight
requests.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97824
Fixes: 821ed7df6e2a ("drm/i915: Update reset path to fix incomplete requests")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Arun Siluvery <arun.siluvery@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160921135108.29574-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_drv.c

@@ -1786,15 +1786,6 @@ void i915_reset(struct drm_i915_private *dev_priv)
 		goto error;
 	}
 
-	/*
-	 * rps/rc6 re-init is necessary to restore state lost after the
-	 * reset and the re-install of gt irqs. Skip for ironlake per
-	 * previous concerns that it doesn't respond well to some forms
-	 * of re-init after reset.
-	 */
-	intel_sanitize_gt_powersave(dev_priv);
-	intel_autoenable_gt_powersave(dev_priv);
-
 wakeup:
 	wake_up_bit(&error->flags, I915_RESET_IN_PROGRESS);
 	return;

drivers/gpu/drm/i915/i915_gem.c

@@ -2628,6 +2628,13 @@ void i915_gem_reset(struct drm_i915_private *dev_priv)
 		i915_gem_reset_engine(engine);
 
 	i915_gem_restore_fences(&dev_priv->drm);
+
+	if (dev_priv->gt.awake) {
+		intel_sanitize_gt_powersave(dev_priv);
+		intel_enable_gt_powersave(dev_priv);
+		if (INTEL_GEN(dev_priv) >= 6)
+			gen6_rps_busy(dev_priv);
+	}
 }
 
 static void nop_submit_request(struct drm_i915_gem_request *request)

drivers/gpu/drm/i915/i915_irq.c

@@ -350,6 +350,9 @@ void gen6_reset_rps_interrupts(struct drm_i915_private *dev_priv)
 
 void gen6_enable_rps_interrupts(struct drm_i915_private *dev_priv)
 {
+	if (READ_ONCE(dev_priv->rps.interrupts_enabled))
+		return;
+
 	spin_lock_irq(&dev_priv->irq_lock);
 	WARN_ON_ONCE(dev_priv->rps.pm_iir);
 	WARN_ON_ONCE(I915_READ(gen6_pm_iir(dev_priv)) & dev_priv->pm_rps_events);
@@ -368,6 +371,9 @@ u32 gen6_sanitize_rps_pm_mask(struct drm_i915_private *dev_priv, u32 mask)
 
 void gen6_disable_rps_interrupts(struct drm_i915_private *dev_priv)
 {
+	if (!READ_ONCE(dev_priv->rps.interrupts_enabled))
+		return;
+
 	spin_lock_irq(&dev_priv->irq_lock);
 	dev_priv->rps.interrupts_enabled = false;