Merge tag 'drm-intel-next-fixes-2018-04-19' of git://anongit.freedesktop.org/drm/drm-intel into drm-next

- Fix for FDO #105549: Avoid OOPS on bad VBT (Jani)
- Fix rare pre-emption race (Chris)
- Fix RC6 race against PM transitions (Tvrtko)

* tag 'drm-intel-next-fixes-2018-04-19' of git://anongit.freedesktop.org/drm/drm-intel:
  drm/i915/audio: Fix audio detection issue on GLK
  drm/i915: Call i915_perf_fini() on init_hw error unwind
  drm/i915/bios: filter out invalid DDC pins from VBT child devices
  drm/i915/pmu: Inspect runtime PM state more carefully while estimating RC6
  drm/i915: Do no use kfree() to free a kmem_cache_alloc() return value
  drm/i915/execlists: Clear user-active flag on preemption completion
  drm/i915/gvt: Add drm_format_mod update
  drm/i915/gvt: Disable primary/sprite/cursor plane at virtual display initialization
  drm/i915/gvt: Delete redundant error message in fb_decode.c
  drm/i915/gvt: Cancel dma map when resetting ggtt entries
  drm/i915/gvt: Missed to cancel dma map for ggtt entries
  drm/i915/gvt: Make MI_USER_INTERRUPT nop in cmd parser
  drm/i915/gvt: Mark expected switch fall-through in handle_g2v_notification
  drm/i915/gvt: throw error on unhandled vfio ioctls

1 files changed, 27 insertions, 10 deletions

diff --git a/drivers/gpu/drm/i915/i915_pmu.c b/drivers/gpu/drm/i915/i915_pmu.c
index d8feb9053e0c..f0519e31543a 100644
--- a/drivers/gpu/drm/i915/i915_pmu.c
+++ b/drivers/gpu/drm/i915/i915_pmu.c
@@ -473,20 +473,37 @@ static u64 get_rc6(struct drm_i915_private *i915)
 		spin_lock_irqsave(&i915->pmu.lock, flags);
 		spin_lock(&kdev->power.lock);
 
-		if (!i915->pmu.sample[__I915_SAMPLE_RC6_ESTIMATED].cur)
-			i915->pmu.suspended_jiffies_last =
-						kdev->power.suspended_jiffies;
+		/*
+		 * After the above branch intel_runtime_pm_get_if_in_use failed
+		 * to get the runtime PM reference we cannot assume we are in
+		 * runtime suspend since we can either: a) race with coming out
+		 * of it before we took the power.lock, or b) there are other
+		 * states than suspended which can bring us here.
+		 *
+		 * We need to double-check that we are indeed currently runtime
+		 * suspended and if not we cannot do better than report the last
+		 * known RC6 value.
+		 */
+		if (kdev->power.runtime_status == RPM_SUSPENDED) {
+			if (!i915->pmu.sample[__I915_SAMPLE_RC6_ESTIMATED].cur)
+				i915->pmu.suspended_jiffies_last =
+						  kdev->power.suspended_jiffies;
 
-		val = kdev->power.suspended_jiffies -
-		      i915->pmu.suspended_jiffies_last;
-		val += jiffies - kdev->power.accounting_timestamp;
+			val = kdev->power.suspended_jiffies -
+			      i915->pmu.suspended_jiffies_last;
+			val += jiffies - kdev->power.accounting_timestamp;
 
-		spin_unlock(&kdev->power.lock);
+			val = jiffies_to_nsecs(val);
+			val += i915->pmu.sample[__I915_SAMPLE_RC6].cur;
 
-		val = jiffies_to_nsecs(val);
-		val += i915->pmu.sample[__I915_SAMPLE_RC6].cur;
-		i915->pmu.sample[__I915_SAMPLE_RC6_ESTIMATED].cur = val;
+			i915->pmu.sample[__I915_SAMPLE_RC6_ESTIMATED].cur = val;
+		} else if (i915->pmu.sample[__I915_SAMPLE_RC6_ESTIMATED].cur) {
+			val = i915->pmu.sample[__I915_SAMPLE_RC6_ESTIMATED].cur;
+		} else {
+			val = i915->pmu.sample[__I915_SAMPLE_RC6].cur;
+		}
 
+		spin_unlock(&kdev->power.lock);
 		spin_unlock_irqrestore(&i915->pmu.lock, flags);
 	}