[PATCH] drm/i915: Inspect subunit states on hangcheck

Mika Kuoppala
2015-12-01T12:17:30Z

If head seems stuck and engine in question is rcs,
inspect subunit state transitions before deciding that
this really is a hang instead of limited progress.

References: https://bugs.freedesktop.org/show_bug.cgi?id=93029
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Gordon <david.s.gordon@intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
---
drivers/gpu/drm/i915/i915_irq.c | 49 +++++++++++++++++++++++++++++----
drivers/gpu/drm/i915/intel_ringbuffer.h | 1 +
2 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index e88d692..e6ae54f 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2913,13 +2913,31 @@ static void semaphore_clear_deadlocks(struct drm_i915_private *dev_priv)
ring->hangcheck.deadlock = 0;
}

-static enum intel_ring_hangcheck_action
-ring_stuck(struct intel_engine_cs *ring, u64 acthd)
+static bool subunits_stuck(struct intel_engine_cs *ring)
{
- struct drm_device *dev = ring->dev;
- struct drm_i915_private *dev_priv = dev->dev_private;
- u32 tmp;
+ int i;
+ u32 instdone[I915_NUM_INSTDONE_REG];
+ bool stuck;
+
+ if (ring->id != RCS)
+ return true;
+
+ i915_get_extra_instdone(ring->dev, instdone);

+ stuck = true;
+ for (i = 0; i < I915_NUM_INSTDONE_REG; i++) {
+ if (instdone[i] != ring->hangcheck.instdone[i])
+ stuck = false;
+
+ ring->hangcheck.instdone[i] = instdone[i];
+ }
+
+ return stuck;
+}
+
+static enum intel_ring_hangcheck_action
+head_stuck(struct intel_engine_cs *ring, u64 acthd)
+{
if (acthd != ring->hangcheck.acthd) {
if (acthd > ring->hangcheck.max_acthd) {
ring->hangcheck.max_acthd = acthd;
@@ -2929,6 +2947,24 @@ ring_stuck(struct intel_engine_cs *ring, u64 acthd)
return HANGCHECK_ACTIVE_LOOP;
}

+ if (!subunits_stuck(ring))
+ return HANGCHECK_ACTIVE_LOOP;
+
+ return HANGCHECK_HUNG;
+}
+
+static enum intel_ring_hangcheck_action
+ring_stuck(struct intel_engine_cs *ring, u64 acthd)
+{
+ struct drm_device *dev = ring->dev;
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ enum intel_ring_hangcheck_action ha;
+ u32 tmp;
+
+ ha = head_stuck(ring, acthd);
+ if (ha != HANGCHECK_HUNG)
+ return ha;
+
if (IS_GEN2(dev))
return HANGCHECK_HUNG;

@@ -3064,6 +3100,9 @@ static void i915_hangcheck_elapsed(struct work_struct *work)
ring->hangcheck.score--;

ring->hangcheck.acthd = ring->hangcheck.max_acthd = 0;
+
+ memset(ring->hangcheck.instdone, 0,
+ sizeof(ring->hangcheck.instdone));
}

ring->hangcheck.seqno = seqno;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 5d1eb20..b8fe92e 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -93,6 +93,7 @@ struct intel_ring_hangcheck {
int score;
enum intel_ring_hangcheck_action action;
int deadlock;
+ u32 instdone[I915_NUM_INSTDONE_REG];
};

struct intel_ringbuffer {
--
2.5.0