1 files changed, 44 insertions, 12 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 8f7187915b0d..308f81913562 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -368,11 +368,12 @@ void __gen6_gt_force_wake_mt_get(struct drm_i915_private *dev_priv)
  */
 void gen6_gt_force_wake_get(struct drm_i915_private *dev_priv)
 {
-        WARN_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex));
+        unsigned long irqflags;
 
-        /* Forcewake is atomic in case we get in here without the lock */
-        if (atomic_add_return(1, &dev_priv->forcewake_count) == 1)
+        spin_lock_irqsave(&dev_priv->gt_lock, irqflags);
+        if (dev_priv->forcewake_count++ == 0)
                 dev_priv->display.force_wake_get(dev_priv);
+        spin_unlock_irqrestore(&dev_priv->gt_lock, irqflags);
 }
 
 void __gen6_gt_force_wake_put(struct drm_i915_private *dev_priv)
@@ -392,10 +393,12 @@ void __gen6_gt_force_wake_mt_put(struct drm_i915_private *dev_priv)
  */
 void gen6_gt_force_wake_put(struct drm_i915_private *dev_priv)
 {
-        WARN_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex));
+        unsigned long irqflags;
 
-        if (atomic_dec_and_test(&dev_priv->forcewake_count))
+        spin_lock_irqsave(&dev_priv->gt_lock, irqflags);
+        if (--dev_priv->forcewake_count == 0)
                 dev_priv->display.force_wake_put(dev_priv);
+        spin_unlock_irqrestore(&dev_priv->gt_lock, irqflags);
 }
 
 void __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv)
@@ -597,9 +600,36 @@ static int ironlake_do_reset(struct drm_device *dev, u8 flags)
 static int gen6_do_reset(struct drm_device *dev, u8 flags)
 {
         struct drm_i915_private *dev_priv = dev->dev_private;
+        int     ret;
+        unsigned long irqflags;
 
-        I915_WRITE(GEN6_GDRST, GEN6_GRDOM_FULL);
-        return wait_for((I915_READ(GEN6_GDRST) & GEN6_GRDOM_FULL) == 0, 500);
+        /* Hold gt_lock across reset to prevent any register access
+         * with forcewake not set correctly
+         */
+        spin_lock_irqsave(&dev_priv->gt_lock, irqflags);
+
+        /* Reset the chip */
+
+        /* GEN6_GDRST is not in the gt power well, no need to check
+         * for fifo space for the write or forcewake the chip for
+         * the read
+         */
+        I915_WRITE_NOTRACE(GEN6_GDRST, GEN6_GRDOM_FULL);
+
+        /* Spin waiting for the device to ack the reset request */
+        ret = wait_for((I915_READ_NOTRACE(GEN6_GDRST) & GEN6_GRDOM_FULL) == 0, 500);
+
+        /* If reset with a user forcewake, try to restore, otherwise turn it off */
+        if (dev_priv->forcewake_count)
+                dev_priv->display.force_wake_get(dev_priv);
+        else
+                dev_priv->display.force_wake_put(dev_priv);
+
+        /* Restore fifo count */
+        dev_priv->gt_fifo_count = I915_READ_NOTRACE(GT_FIFO_FREE_ENTRIES);
+
+        spin_unlock_irqrestore(&dev_priv->gt_lock, irqflags);
+        return ret;
 }
 
 /**
@@ -643,9 +673,6 @@ int i915_reset(struct drm_device *dev, u8 flags)
         case 7:
         case 6:
                 ret = gen6_do_reset(dev, flags);
-                /* If reset with a user forcewake, try to restore */
-                if (atomic_read(&dev_priv->forcewake_count))
-                        __gen6_gt_force_wake_get(dev_priv);
                 break;
         case 5:
                 ret = ironlake_do_reset(dev, flags);
@@ -927,9 +954,14 @@ MODULE_LICENSE("GPL and additional rights");
 u##x i915_read##x(struct drm_i915_private *dev_priv, u32 reg) { \
         u##x val = 0; \
         if (NEEDS_FORCE_WAKE((dev_priv), (reg))) { \
-                gen6_gt_force_wake_get(dev_priv); \
+                unsigned long irqflags; \
+                spin_lock_irqsave(&dev_priv->gt_lock, irqflags); \
+                if (dev_priv->forcewake_count == 0) \
+                        dev_priv->display.force_wake_get(dev_priv); \
                 val = read##y(dev_priv->regs + reg); \
-                gen6_gt_force_wake_put(dev_priv); \
+                if (dev_priv->forcewake_count == 0) \
+                        dev_priv->display.force_wake_put(dev_priv); \
+                spin_unlock_irqrestore(&dev_priv->gt_lock, irqflags); \
         } else { \
                 val = read##y(dev_priv->regs + reg); \
         } \