4 files changed, 65 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 7a73b2941eb7..08a5048335e1 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1447,6 +1447,8 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
         if (!IS_IGDNG(dev))
                 intel_opregion_init(dev, 0);
 
+        setup_timer(&dev_priv->hangcheck_timer, i915_hangcheck_elapsed,
+                    (unsigned long) dev);
         return 0;
 
 out_workqueue_free:
@@ -1467,6 +1469,7 @@ int i915_driver_unload(struct drm_device *dev)
         struct drm_i915_private *dev_priv = dev->dev_private;
 
         destroy_workqueue(dev_priv->wq);
+        del_timer_sync(&dev_priv->hangcheck_timer);
 
         io_mapping_free(dev_priv->mm.gtt_mapping);
         if (dev_priv->mm.gtt_mtrr >= 0) {
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 933d832aeff7..afbcaa9866f4 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -203,6 +203,12 @@ typedef struct drm_i915_private {
         unsigned int sr01, adpa, ppcr, dvob, dvoc, lvds;
         int vblank_pipe;
 
+        /* For hangcheck timer */
+#define DRM_I915_HANGCHECK_PERIOD 75 /* in jiffies */
+        struct timer_list hangcheck_timer;
+        int hangcheck_count;
+        uint32_t last_acthd;
+
         bool cursor_needs_physical;
 
         struct drm_mm vram;
@@ -620,6 +626,7 @@ extern int i915_emit_box(struct drm_device *dev,
                          int i, int DR1, int DR4);
 
 /* i915_irq.c */
+void i915_hangcheck_elapsed(unsigned long data);
 extern int i915_irq_emit(struct drm_device *dev, void *data,
                          struct drm_file *file_priv);
 extern int i915_irq_wait(struct drm_device *dev, void *data,
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index c70e91b51f67..579b3b04ff12 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1584,8 +1584,11 @@ i915_add_request(struct drm_device *dev, struct drm_file *file_priv,
 
         }
 
-        if (was_empty && !dev_priv->mm.suspended)
-                queue_delayed_work(dev_priv->wq, &dev_priv->mm.retire_work, HZ);
+        if (!dev_priv->mm.suspended) {
+                mod_timer(&dev_priv->hangcheck_timer, jiffies + DRM_I915_HANGCHECK_PERIOD);
+                if (was_empty)
+                        queue_delayed_work(dev_priv->wq, &dev_priv->mm.retire_work, HZ);
+        }
         return seqno;
 }
 
@@ -3896,6 +3899,7 @@ i915_gem_idle(struct drm_device *dev)
          * We need to replace this with a semaphore, or something.
          */
         dev_priv->mm.suspended = 1;
+        del_timer(&dev_priv->hangcheck_timer);
 
         /* Cancel the retire work handler, wait for it to finish if running
          */
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 6c89f2ff2495..77e42e719d7d 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -601,6 +601,8 @@ irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
                 if (iir & I915_USER_INTERRUPT) {
                         dev_priv->mm.irq_gem_seqno = i915_get_gem_seqno(dev);
                         DRM_WAKEUP(&dev_priv->irq_queue);
+                        dev_priv->hangcheck_count = 0;
+                        mod_timer(&dev_priv->hangcheck_timer, jiffies + DRM_I915_HANGCHECK_PERIOD);
                 }
 
                 if (pipea_stats & vblank_status) {
@@ -880,6 +882,53 @@ int i915_vblank_swap(struct drm_device *dev, void *data,
         return -EINVAL;
 }
 
+struct drm_i915_gem_request *i915_get_tail_request(struct drm_device *dev) {
+        drm_i915_private_t *dev_priv = dev->dev_private;
+        return list_entry(dev_priv->mm.request_list.prev, struct drm_i915_gem_request, list);
+}
+
+/**
+ * This is called when the chip hasn't reported back with completed
+ * batchbuffers in a long time. The first time this is called we simply record
+ * ACTHD. If ACTHD hasn't changed by the time the hangcheck timer elapses
+ * again, we assume the chip is wedged and try to fix it.
+ */
+void i915_hangcheck_elapsed(unsigned long data)
+{
+        struct drm_device *dev = (struct drm_device *)data;
+        drm_i915_private_t *dev_priv = dev->dev_private;
+        uint32_t acthd;
+       
+        if (!IS_I965G(dev))
+                acthd = I915_READ(ACTHD);
+        else
+                acthd = I915_READ(ACTHD_I965);
+
+        /* If all work is done then ACTHD clearly hasn't advanced. */
+        if (list_empty(&dev_priv->mm.request_list) ||
+                       i915_seqno_passed(i915_get_gem_seqno(dev), i915_get_tail_request(dev)->seqno)) {
+                dev_priv->hangcheck_count = 0;
+                return;
+        }
+
+        if (dev_priv->last_acthd == acthd && dev_priv->hangcheck_count > 0) {
+                DRM_ERROR("Hangcheck timer elapsed... GPU hung\n");
+                dev_priv->mm.wedged = true; /* Hopefully this is atomic */
+                i915_handle_error(dev);
+                return;
+        } 
+
+        /* Reset timer case chip hangs without another request being added */
+        mod_timer(&dev_priv->hangcheck_timer, jiffies + DRM_I915_HANGCHECK_PERIOD);
+
+        if (acthd != dev_priv->last_acthd)
+                dev_priv->hangcheck_count = 0;
+        else
+                dev_priv->hangcheck_count++;
+
+        dev_priv->last_acthd = acthd;
+}
+
 /* drm_dma.h hooks
 */
 static void igdng_irq_preinstall(struct drm_device *dev)