[RFC 4/6] drm/i915: add runtime put/get calls at the basic places

[Paulo Zanoni <przanoni@gmail.com>]

From: Paulo Zanoni <paulo.r.zanoni@intel.com>

If I add code to enable runtime PM on my Haswell machine, start a
desktop environment, then enable runtime PM, these functions will
complain that they're trying to read/write registers while the
graphics card is suspended.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c            | 53 +++++++++++++++++++-----------
 drivers/gpu/drm/i915/i915_gem_execbuffer.c |  6 ++++
 drivers/gpu/drm/i915/i915_irq.c            |  6 ++++
 3 files changed, 46 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index e7b39d7..e7c2581 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1377,36 +1377,38 @@ int i915_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	pgoff_t page_offset;
 	unsigned long pfn;
-	int ret = 0;
+	int rc = 0, ret;
 	bool write = !!(vmf->flags & FAULT_FLAG_WRITE);
 
+	intel_runtime_pm_get(dev_priv);
+
 	/* We don't use vmf->pgoff since that has the fake offset */
 	page_offset = ((unsigned long)vmf->virtual_address - vma->vm_start) >>
 		PAGE_SHIFT;
 
-	ret = i915_mutex_lock_interruptible(dev);
-	if (ret)
+	rc = i915_mutex_lock_interruptible(dev);
+	if (rc)
 		goto out;
 
 	trace_i915_gem_object_fault(obj, page_offset, true, write);
 
 	/* Access to snoopable pages through the GTT is incoherent. */
 	if (obj->cache_level != I915_CACHE_NONE && !HAS_LLC(dev)) {
-		ret = -EINVAL;
+		rc = -EINVAL;
 		goto unlock;
 	}
 
 	/* Now bind it into the GTT if needed */
-	ret = i915_gem_obj_ggtt_pin(obj,  0, true, false);
-	if (ret)
+	rc = i915_gem_obj_ggtt_pin(obj,  0, true, false);
+	if (rc)
 		goto unlock;
 
-	ret = i915_gem_object_set_to_gtt_domain(obj, write);
-	if (ret)
+	rc = i915_gem_object_set_to_gtt_domain(obj, write);
+	if (rc)
 		goto unpin;
 
-	ret = i915_gem_object_get_fence(obj);
-	if (ret)
+	rc = i915_gem_object_get_fence(obj);
+	if (rc)
 		goto unpin;
 
 	obj->fault_mappable = true;
@@ -1416,19 +1418,21 @@ int i915_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 	pfn += page_offset;
 
 	/* Finally, remap it using the new GTT offset */
-	ret = vm_insert_pfn(vma, (unsigned long)vmf->virtual_address, pfn);
+	rc = vm_insert_pfn(vma, (unsigned long)vmf->virtual_address, pfn);
 unpin:
 	i915_gem_object_unpin(obj);
 unlock:
 	mutex_unlock(&dev->struct_mutex);
 out:
-	switch (ret) {
+	switch (rc) {
 	case -EIO:
 		/* If this -EIO is due to a gpu hang, give the reset code a
 		 * chance to clean up the mess. Otherwise return the proper
 		 * SIGBUS. */
-		if (i915_terminally_wedged(&dev_priv->gpu_error))
-			return VM_FAULT_SIGBUS;
+		if (i915_terminally_wedged(&dev_priv->gpu_error)) {
+			ret = VM_FAULT_SIGBUS;
+			break;
+		}
 	case -EAGAIN:
 		/*
 		 * EAGAIN means the gpu is hung and we'll wait for the error
@@ -1443,15 +1447,22 @@ out:
 		 * EBUSY is ok: this just means that another thread
 		 * already did the job.
 		 */
-		return VM_FAULT_NOPAGE;
+		ret = VM_FAULT_NOPAGE;
+		break;
 	case -ENOMEM:
-		return VM_FAULT_OOM;
+		ret = VM_FAULT_OOM;
+		break;
 	case -ENOSPC:
-		return VM_FAULT_SIGBUS;
+		ret = VM_FAULT_SIGBUS;
+		break;
 	default:
-		WARN_ONCE(ret, "unhandled error in i915_gem_fault: %i\n", ret);
-		return VM_FAULT_SIGBUS;
+		WARN_ONCE(rc, "unhandled error in i915_gem_fault: %i\n", rc);
+		ret = VM_FAULT_SIGBUS;
+		break;
 	}
+
+	intel_runtime_pm_put(dev_priv);
+	return ret;
 }
 
 /**
@@ -4164,6 +4175,8 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj)
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	struct i915_vma *vma, *next;
 
+	intel_runtime_pm_get(dev_priv);
+
 	trace_i915_gem_object_destroy(obj);
 
 	if (obj->phys_obj)
@@ -4208,6 +4221,8 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj)
 
 	kfree(obj->bit_17);
 	i915_gem_object_free(obj);
+
+	intel_runtime_pm_put(dev_priv);
 }
 
 struct i915_vma *i915_gem_obj_to_vma(struct drm_i915_gem_object *obj,
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 0ce0d47..0b2f200 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1062,6 +1062,8 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 		}
 	}
 
+	intel_runtime_pm_get(dev_priv);
+
 	ret = i915_mutex_lock_interruptible(dev);
 	if (ret)
 		goto pre_mutex_err;
@@ -1197,6 +1199,10 @@ err:
 
 pre_mutex_err:
 	kfree(cliprects);
+
+	/* intel_gpu_busy should also get a ref, so it will free when the device
+	 * is really idle. */
+	intel_runtime_pm_put(dev_priv);
 	return ret;
 }
 
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 1a7dc77..1ded745 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2242,6 +2242,12 @@ static void i915_hangcheck_elapsed(unsigned long data)
 	if (!i915_enable_hangcheck)
 		return;
 
+	/* Just postpone in case we're completely idle... */
+	if (dev_priv->pm.suspended) {
+		i915_queue_hangcheck(dev);
+		return;
+	}
+
 	for_each_ring(ring, dev_priv, i) {
 		u32 seqno, acthd;
 		bool busy = true;
-- 
1.8.3.1