drm/i915: Lock down psr sw/hw state tracking

Make sure we track the sw side (psr.active) correctly and WARN
everywhere it might get out of sync with the hw.

v2: Fixup WARN_ON logic inversion, reported by Rodrigo.

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 23 insertions, 20 deletions

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 0184188b3a2d..f630c23a7bd6 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1834,8 +1834,8 @@ static void intel_edp_psr_do_enable(struct intel_dp *intel_dp)
         struct drm_device *dev = intel_dig_port->base.base.dev;
         struct drm_i915_private *dev_priv = dev->dev_private;
 
-        if (intel_edp_is_psr_enabled(dev))
-                return;
+        WARN_ON(I915_READ(EDP_PSR_CTL(dev)) & EDP_PSR_ENABLE);
+        WARN_ON(dev_priv->psr.active);
 
         /* Enable PSR on the panel */
         intel_edp_psr_enable_sink(intel_dp);
@@ -1876,13 +1876,19 @@ void intel_edp_psr_disable(struct intel_dp *intel_dp)
         if (!dev_priv->psr.enabled)
                 return;
 
-        I915_WRITE(EDP_PSR_CTL(dev),
-                   I915_READ(EDP_PSR_CTL(dev)) & ~EDP_PSR_ENABLE);
+        if (dev_priv->psr.active) {
+                I915_WRITE(EDP_PSR_CTL(dev),
+                           I915_READ(EDP_PSR_CTL(dev)) & ~EDP_PSR_ENABLE);
+
+                /* Wait till PSR is idle */
+                if (_wait_for((I915_READ(EDP_PSR_STATUS_CTL(dev)) &
+                               EDP_PSR_STATUS_STATE_MASK) == 0, 2000, 10))
+                        DRM_ERROR("Timed out waiting for PSR Idle State\n");
 
-        /* Wait till PSR is idle */
-        if (_wait_for((I915_READ(EDP_PSR_STATUS_CTL(dev)) &
-                       EDP_PSR_STATUS_STATE_MASK) == 0, 2000, 10))
-                DRM_ERROR("Timed out waiting for PSR Idle State\n");
+                dev_priv->psr.active = false;
+        } else {
+                WARN_ON(I915_READ(EDP_PSR_CTL(dev)) & EDP_PSR_ENABLE);
+        }
 
         dev_priv->psr.enabled = NULL;
 }
@@ -1900,16 +1906,6 @@ static void intel_edp_psr_work(struct work_struct *work)
                 intel_edp_psr_do_enable(intel_dp);
 }
 
-static void intel_edp_psr_inactivate(struct drm_device *dev)
-{
-        struct drm_i915_private *dev_priv = dev->dev_private;
-
-        dev_priv->psr.active = false;
-
-        I915_WRITE(EDP_PSR_CTL(dev), I915_READ(EDP_PSR_CTL(dev))
-                   & ~EDP_PSR_ENABLE);
-}
-
 void intel_edp_psr_exit(struct drm_device *dev)
 {
         struct drm_i915_private *dev_priv = dev->dev_private;
@@ -1922,8 +1918,15 @@ void intel_edp_psr_exit(struct drm_device *dev)
 
         cancel_delayed_work_sync(&dev_priv->psr.work);
 
-        if (dev_priv->psr.active)
-                intel_edp_psr_inactivate(dev);
+        if (dev_priv->psr.active) {
+                u32 val = I915_READ(EDP_PSR_CTL(dev));
+
+                WARN_ON(!(val & EDP_PSR_ENABLE));
+
+                I915_WRITE(EDP_PSR_CTL(dev), val & ~EDP_PSR_ENABLE);
+
+                dev_priv->psr.active = false;
+        }
 
         schedule_delayed_work(&dev_priv->psr.work,
                               msecs_to_jiffies(100));