drm/i915: Avoid tweaking RPS before it is enabled

As we delay the initial RPS enabling (upon boot and after resume), there
is a chance that we may start to render and trigger RPS boosts before we
set up the punit. Any changes we make could result in inconsistent
hardware state, with a danger of causing undefined behaviour. However,
as the boosting is a optional tweak to RPS, we can simply ignore it
whilst RPS is not yet enabled.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

2 files changed, 17 insertions, 10 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 9cac93c41e10..36b82cc48b4c 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -862,6 +862,7 @@ struct intel_gen6_power_mgmt {
         int last_adj;
         enum { LOW_POWER, BETWEEN, HIGH_POWER } power;
 
+        bool enabled;
         struct delayed_work delayed_resume_work;
 
         /*
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index c91087a542ec..ca3dd566974a 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3442,22 +3442,26 @@ void gen6_set_rps(struct drm_device *dev, u8 val)
 void gen6_rps_idle(struct drm_i915_private *dev_priv)
 {
         mutex_lock(&dev_priv->rps.hw_lock);
-        if (dev_priv->info->is_valleyview)
-                valleyview_set_rps(dev_priv->dev, dev_priv->rps.min_delay);
-        else
-                gen6_set_rps(dev_priv->dev, dev_priv->rps.min_delay);
-        dev_priv->rps.last_adj = 0;
+        if (dev_priv->rps.enabled) {
+                if (dev_priv->info->is_valleyview)
+                        valleyview_set_rps(dev_priv->dev, dev_priv->rps.min_delay);
+                else
+                        gen6_set_rps(dev_priv->dev, dev_priv->rps.min_delay);
+                dev_priv->rps.last_adj = 0;
+        }
         mutex_unlock(&dev_priv->rps.hw_lock);
 }
 
 void gen6_rps_boost(struct drm_i915_private *dev_priv)
 {
         mutex_lock(&dev_priv->rps.hw_lock);
-        if (dev_priv->info->is_valleyview)
-                valleyview_set_rps(dev_priv->dev, dev_priv->rps.max_delay);
-        else
-                gen6_set_rps(dev_priv->dev, dev_priv->rps.max_delay);
-        dev_priv->rps.last_adj = 0;
+        if (dev_priv->rps.enabled) {
+                if (dev_priv->info->is_valleyview)
+                        valleyview_set_rps(dev_priv->dev, dev_priv->rps.max_delay);
+                else
+                        gen6_set_rps(dev_priv->dev, dev_priv->rps.max_delay);
+                dev_priv->rps.last_adj = 0;
+        }
         mutex_unlock(&dev_priv->rps.hw_lock);
 }
 
@@ -4716,6 +4720,7 @@ void intel_disable_gt_powersave(struct drm_device *dev)
                         valleyview_disable_rps(dev);
                 else
                         gen6_disable_rps(dev);
+                dev_priv->rps.enabled = false;
                 mutex_unlock(&dev_priv->rps.hw_lock);
         }
 }
@@ -4735,6 +4740,7 @@ static void intel_gen6_powersave_work(struct work_struct *work)
                 gen6_enable_rps(dev);
                 gen6_update_ring_freq(dev);
         }
+        dev_priv->rps.enabled = true;
         mutex_unlock(&dev_priv->rps.hw_lock);
 }